As mentioned in earlier posts I’m finishing off the wiring on a fairly major addition that doubles the sq ft of my home and is four stories high. I’m finishing up with the phone lines, dsl, etc. and now will complete the job with cable.
What I’m wondering is this: How ‘ok’ is it to run tv cable alongside of cat5e phone line? What ‘kind’ of cable should I get? .. (are there various kinds?) And is the cable that I would run for local Comcast Cable the same as for Dish Networks cable if someone in the addition eventually wants to go with satellite?
Thanks!
Replies
RJ6 with home runs to your distribution panel.
Try to cheat and your resale value goes down.
Or, you'll have to re-do it when the picture goes bad. Which will be soon.
Code-wise, you can run them (TV and Cat-5) together -- they're both low-voltage, current-limited cables that are regarded essentially the same by the NEC. As to crosstalk (interference between cables), there could in theory be some, but probably negligible in a residential setting.
For regular TV signals you generally should use RG-6 cable. RG-59 (smaller diameter) can also be used but is generally considered to be inferior. But keep in mind that there are varying qualities of RG-6 as well.
I'm not sure what's typically used with satellite dishes.
Usually the installers will want to run their own new cable. You might want to check with them about wiring your house. It's possible that the best thing for you to do us make wide conduit paths to the different areas, then let them run their own wires, connections, and splitters.
Tu stultus es
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
Look, just send me to my drawer. This whole talking-to-you thing is like double punishment.
Or else, those installers will drape the cable along your gutters and poke a hole in a window screen somewhere.
They don't care.
Exactly. The only thing they care about is delivering a clean signal to your TV's. How the cables look getting their is not their concern!
Tu stultus esRebuilding my home in Cypress, CAAlso a CRX fanatic!
Look, just send me to my drawer. This whole talking-to-you thing is like double punishment.
I would use a quality RG6 cable that is from a reputable company. If you are wanting to make sure it's suitable for satellite use, it needs to be rated for 3 GHz.
***Edit***
I was wrong, it is 3GHz.
This website might help:
http://www.avsforum.com/avs-vb/showthread.php?p=15492516#post15492516
And by all means make sure they are all home runs.
Edited 8/10/2009 5:15 pm ET by JoshRountree
When you guys refer to 'home runs' I take it that you mean EACH floor has a line running all the way back to the source box? I.e., don't run a run from one flr to the next, cut it there and staple, then, another line from there to the next, cut it there and staple ....
I just spoke with Comcast Cable and with Direct TV satellite and was told RG-6 by both of them. The satellite guy in Denver told me that they have 24 satellites hovering over the equator each at 23,257 feet up. All of them were launched from "an old oil rid platform in the Caribbean".
Guess I gotta head out and buy a ton of coaxial cable today!
A~
"When you guys refer to 'home runs' I take it that you mean EACH floor has a line running all the way back to the source box?"
NO!
Each room where a cable jack is to be located (or more if you got multiple TV's in the same room, such as the three in my poker room) has at LEAST one "home run" going all the way back to your "distribution panel." The distribution panel is between your source box (where the cable guys toy with the wires) and the cable jacks in the rooms.
In fact, the more modern and well fitted video distribution setups will have TWO for each outlet jack. One for the signal coming from the distribution panel and another for a signal going to the panel. The reason being, should you have a CCTV camera in the babies room to see if she's awake, you can simply change the channel in any room to the one that has the babies camera showing. Or the DVD player in the media room sending it's signal out to the other TV's in the house. Or your security system's camera.
Here's one explanation: http://www.smarthome.com/SLCsolution132.html
Or this to keep you busy: http://www.smarthome.com/_/Speakers_A_V_Home_Theater/A_V_Distribution_Wired/_/R/1SZ/nav.aspx
This is an example of a distribution panel: http://www.smarthome.com/7711B/Channel-Vision-3-Input-x-12-Output-Video-Distribution-Panels-DP-3-12-II/p.aspx
And more choices here: http://www.smarthome.com/_/Cable_Structured_Wiring/Structured_Panels_Accessories/_/v/1P3/nav.aspx
Of course, you could go wireless...
God Almighty I hate wiring.
LOVE plumbing (who'd a thunk it) ..
but HATE all this wiring.
~ gotta be done tho ~
refer to 'home runs' I take it that you mean EACH floor
LoL! Not that my cable people would do anything so contentious as publish a minimum specification (they'd have to hold to that, if they did), but, the "tech spec" is to blame all cable problems of your splitters (not theirs).
Their unstated idea is typically, each room run back to a distribution panel.
That can be complicated. Guy driving the cable van sometimes, not so much.Occupational hazard of my occupation not being around (sorry Bubba)
"it needs to be rated for 3000 Hz or 3 MHz."3000 Hz is 3 kHz. Both are wrong. It's 3 Ghz.The best things in life aren't things.
> If you are wanting to make sure it's suitable for satellite use, it needs to be rated for 3000 Hz or 3 MHz. I suppose if I **had** to choose between the two I'd take the one rated for 3MHz, but I'd really prefer something rated a couple of thousand MHz, I'm thinking.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Home Depot sells Rg-6 Quade Shield Copper Clad cable for 100 ft @ $16.50 or 500 ft @ $42.00. They usually sell it by the running foot for fifty cents but right now they are selling it by the foot on sale for 11 cents! I only need 200 ft max. ((Why am I saying this? I have no idea. Maybe because 11 cents sounds so cheap!))
Gee, I think I'll run out tonight and buy a foot!
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
you reeeeally should!
you'll never beat that price again!!!
How 'ok' is it to run tv cable alongside of cat5e phone line?
RG-6Q (Quad Shield). No problem running it alongside voice/data wiring. Similar rules as for voice/data - wire ties should not be cinched tight, gentle bends, etc. In fact, structured cable assemblies are available that contain both RG-6 and Cat. 5e (usually 2 of each) within an outer jacket that looks and feels pretty much like garden hose. You can't get much closer together than that...
Bob
Edited for spelling
Edited 8/7/2009 5:38 pm ET by bobguindon
Congrats on the major addition.
As others have said, run RG-6 quad sheild.
Install at least one run (cable) from each outlet location back to a central location (a walk-in closet is good) for the distribution or patch panel. Each home run needs to be unbroken, or continuous. IF you goof and put a staple into the cable, DO NOT put in a splice. Pull the cable out and run new.
From the patch panel, also run two RG-6 to the sat. dish location, and two to the place where the cable company is bringing serrvice to your house.
One more thing, and this is important: install a home run of phone cable (cat 5 4-pair) to the patch panel AND to each TV outlet location where you think you might install a TIVO...the sat. decoder box and each TIVO need a phone line for billing.
You think 200 ft will be enough? I've run five times that in a 2200 SF house...
A couple other thoughts:
--keep the coax (RG-6) and phone wire at least 12" away from power wiring, and more is better. Code (NEC) says 2" is the minimum separation so that a power surge won't arc over from line voltage wiring to low voltage. If phone or coax and power wiring must cross, keep 2" or more separation and have them cross at right angles.
--when stapling the coax, use Arrow t-59 staples (with the plastic bushing), or hammer-driven romex staples with the plastic cross piece. Especially don't use a gun-driven metal staple (arrow t-37 or similar) that'll tightly pinch the cable. Any staple needs to be just snug enough to hold the cable, and not deform or pinch it.
--run a 10 gage insulated ground wire from the cable tv box to the electrical panel; the cable company needs to ground the lightning arrestor that their incoming signal feeds through.
--put a receptacle outlet at the TV patch panel location, in case you need a powered amplifier for the video signal.
Good luck!
Cliff
wow.
thanks for this.
I'm glad I haven't started actually stringing the coax yet ..
Begin this weekend.
RG6 quad shield is the current FHB standard.
Something to understand about cross talk between electrical and phone/data/video cable is that elect and d/d/v cable run close and parallel to each other is very bad. If there in proximity with each other but at right angles (roughly) the cross talk thing is much less.
A few other things.... Some satellite systems require 2 RG cables to be run from the dish location to the video system location. Also some satellite systems require a phone line at the video system location, which I think is for pay per view services.
Edited 8/7/2009 8:28 pm ET by Matt
Very timely topic simce I am almost ready to run cables for the small remodel I'm doing. One question I have is how long can the coax be between the satellite and the TV? I "need" to have a new feed to my shop since the switch to digital and it's about 150 feet from the dish. I could see some home runs in a large house being this long. Maybe need a signal booster?
PS: Passed the rough inspection this morning. My first.
Jim
I have been asked by two different installers for satellite "You're not planning on going over 300 feet away, are you?" (It may even have been 500). So you should be ok. But if you're still nervous just call the satellity installation guys in your area .. the ones that the big satellite companys contract with to do their local instalations.
It IS ok to run the RG-6 outside as well .. right?
Pretty moderate climate here .. but definitely 'a little moisture' from time to time. But I notice that my cable company runs their lines outside all over the place.
It IS ok to run the RG-6 outside as well .. right?
The only issue with running RG-6 outside is UV exposure. Generally, the black cable is rated for UV exposure, but the white is not. It won't take but a few years for non-UV rated cable jacket to break down in the sunlight.
As far as aesthetics go, the cable installers are looking to get in and get out as quickly as possible - with a a little effort, most wiring can be fished or otherwise concealed.
Bob
Even the black RG-6 is probably only going to hold spec (when exposed to outside sunlight) for 10 years or so before it degrades, and 20 years is maybe it's practical lifetime. I'm reasonably certain that the cable guys use something with a higher UV resistance for their drops.So it's best to minimize outside exposure, and make it so that the outside elements can be replaced with relative ease when needed.Also, one should keep in mind that cable that is exposed to potential lightning strikes needs to be separated via lightning arrestors from the rest of the system. I don't recall all the specifics, but generally if a wire is run from building to building, either overhead or in shallow burial, it's going to need this treatment.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Edited 8/8/2009 9:25 pm by DanH
I notice that Comcast provides the service in your area. You should at least ask them if they will provide (free) the coaxial you need. Years ago, I did (before I was a cable customer), and they asked me how many feet I wanted and dropped it off -- gratis. Another time I saw a Comcast truck in the alley, told the guy I needed another 200 feet of wire and he gave it to me on the spot -- also gave me the connectors I needed. That was a long time ago, but it is worth a phone call to see if they will help you out.********************************************************
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
Whoa!!! nikkiwood!
Thank you for that! Ha! I'll definitely give a call and see what they say!
Absolutely NEVER would've occured to me, that one ..
A~
If you do make the call, you will probably get resistance from the first customer service rep that takes your call. Ask to speak to the installation forman for your geographic area. He will understand it is cost effective for Comcast to give you the cable now (gratis), rather than make them run it when you order up service at some point in the future. In my case, it paid off big for them: we now buy TV and internet broadband from Comcast, and we just switched to them for telephone service (2 lines).********************************************************
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
I called and talked to a guy today who's little company is often contracted to install the dishes for dish networks and other satellite dish companies. I asked him what he would do in my situation and he said that if I wanted to really stay completely current and not have to break into the walls to put in more lines down the line that he would decide where the best place for a dish would be and he would run FOUR rg-6 lines from that spot down to a patch panel. Then run to each likely tv location making sure that there was also a cat-5 line in near each endpoint. Then, he would run a line from the outside cable box in to the panel as well to leave open the opportunity for cable for whomever might want it in the future. Said that his installers follow the rule of leaving at LEAST 12 inches between LV lines of any kind and standard electrical lines (12-2wg e.g.). Said, "it's ok to cross a line .. but NOT to parallel a line".
I told him that I had already installed the cat-5 and that I had NOT done the panel with home runs routine and had daisy chained some of them along and he said that he thought that I'd have no problems with that but that the RG-6 was different and should be done with panels and homeruns.
Four coax's from the potential dish site .. NEVER woulda done that. But since the walls are all open and it aint that expensive I'm thinkin I will. I looked at the boxes today .. the 'distribution panels' .. on Amazon and some of them are expensive! Over 300 smackers! There are some for under a hundred also .. but my own phone company just put in a cheap plastic box studded with little metal bristles that they 'punch' wires down on to and call it good! That little 3 x 4 inch white plastic porcupine can't cost more than a couple of dollars each!
Oh well ...
That's known as a punch-down block. Good for connecting phone lines, should not be used for connecting ethernet (unless it's one of the specialized units).The best thing to do for connections at the main hub point is to install a large (2x3 or larger) piece of 1/2" plywood and leave the cables long enough to reach all the way to the far edge. Don't trim the cables as you terminate them (to, eg, splitters screwed to the plywood) but leave them long. A slightly messy look is not a bad thing here.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Run more cables than you can possibly ever imagine needing. Especially network drops. At least one, preferably 2 network drops at each TV location. TV has gone digital and so has music. Individual runs back to a central panel. SPend the extra $ for Cat6 over Cat5e. It will never be as cheap as it is when the walls are open to run these. Landlines may be going the way of the dinosaur, but for now we still need them. I ran Cat3 for phone lines (lots of them). Every TV location got two Cable drops and a network drop.
Well, if you really want insurance for the future you should run conduit.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
I second that.
Smurf tube (the blue corrugated stuff, aka electrical nonmetallic tubing, or ENT), 3/4". Just run it to the top of the low-v rings, use a fish tape to pull in a pull string.
Cliff
Wasn't there some guy in FH who did an article sometime back on working with electrical who stated that, as a favor to himself or to future electrical workers in the house, he alway put in a conduit from floor to floor and left it open/empty? The idea was that as long as it was general homeowner knowledge where that open vertical conduit was it would always be relatively easy to run wires up or down floor to floor in the future with just one or two very small holes in the drywall instead of ripping the hell out of everything. A 10 ft. grey plastic tube, 3/4", costs less than 2 bucks at HD. Sounded like a pretty good idea to me. I guess you'd have to drill through the sills and macth them up floor to floor.
I've made that suggestion a few times -- run a couple of unused conduits between the various obvious distribution points for wiring -- utility room to attic, utility room to garage, etc.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
The best thing to do for connections at the main hub point is to install a large (2x3 or larger) piece of 1/2" plywood and leave the cables long enough to reach all the way to the far edge. Don't trim the cables as you terminate them (to, eg, splitters screwed to the plywood) but leave them long. A slightly messy look is not a bad thing here.
=============================================
this sounds good to me. Sounds a bit like I had in mind for now as I'm tucking it into the back of a closet, but I thought that I'd have to eventually buy a fancy distribution box to hide it in. Are you suggesting here that then, later, you can grab the ones that you need and hook them up individually as the need arises and simply leave the other 'potentials' hanging?
Yep, that's the idea. Leave them hanging (or neatly coiled, if you prefer). So long as it's not on the living room wall, who cares how it looks? And why buy a fancy cabinet to connect things one way when you're not sure how you want them connected, or will want them in the future?
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Excellent. This is an example of one of those little exchanges that is going to make all the difference for me not only in labor but in peace of mind. This is the sort of thing that I'm always thinking "why can't I just ..." but I always feel that I better do it the way that's being shown and recommended by those who want to sell me their fancy box or whatever. So .. I'll run the lines and leave 'em hanging and clearly labelled where they come from / go to. The cable or satellite guy can hook 'em up however they see fit down the line.
Thanks!
If you want to get fancy you can get some of the metal hoops (not sure what they're called) that the phone companies use to route wire through on similar boards. Probably cost you $1-2 a throw and you'd need 8-10 of them. Won't make the setup any better, but it will look a little more professional, at minimal cost.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Hmmmm..... metal 'hoops'?
Can you give me any further clues on what these are exactly? Are they simply for 'neatness' at the board? Or do they later serve in hook-ups? Are they available to us retail? Or are they proprietary to the ph co? ???
You know the sort of miniature version of a nautical cleat that folks use to tie off, eg, clotheslines? Well, envision that cleat with one arm cut off and the other arm extended to about 10-15 inches, then bent around in 3/4s of a square, plus a little more. You screw these every 6-10 inches around the perimeter of the board and then run the wires inside the squares. They just loosely constrain the cables, without getting in the way very much.Unfortunately, I don't know the name of the thing to look it up. (Maybe someone else can help?)Other schemes for keeping things (cheaply) neat include running in a small screw eye every few inches around the perimeter and then using these to anchor cable ties.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Unfortunately I don't totally get it .. but I'll keep my eyes peeled for what you may mean. If I find them and end up using them I'll post a pic. If you've seen it used it must be available out there.
thanks -
I am not sure what Dan is talking about either. But his comments does ring a bell.But here is some stuff to look at.Panduit ducts.https://www.mouser.com/catalog/639/1039.PDFI particular those shown in figure C.And these J hooks might have been what Dan was talking about.http://www.mouser.com/catalog/639/1038.pdfA few months ago I was looking for an residential phone block and found a whole different market than the electronic or electrical suppliers that it and I think more of the home tv/phone wiring stuff than either of the other suppliers that I was used to. This is what I got http://www.pacificcable.com/Picture_Page.asp?DataName=550-020Fast Home Media 550-020 or Steren 550-020.Google those and the people that sell them probably have other stuff..
William the Geezer, the sequel to Billy the Kid - Shoe
excellent.... thanks ..
The concept of having a few extra feet of cable at the backboard/distribution point is called a "service loop" in the trades.
The cable support is called a drive ring. See this link:
http://www.seniorindustries.com/ProductInfo.aspx?productid=SI-6863
A similar piece of hardware the screws into the framing is called a bridle ring.
Arlington industries has cable supports of all sorts, good if you're running 50 or more cables. Drive rings work just great for most residential installs.
Cliff
Well, that wasn't what I was talking about either, but it would do, more or less.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
I was thinking d rings http://www.newtechindustries.com/newtech/images/accessories/Dring3m.jpgsometimes I'll use these PVC pipe clamps http://ec-images.acehardwareoutlet.com/225/products/998017380_140907_DV.jpg
Edited 8/12/2009 5:53 pm ET by skip555
Ah! Very simple.
Simple is good.
thanks -
Yeah, that's basically what I was talking about, only open on one side.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
that's what a hacksaw's for depending on the application we just cut them in half when need be
Here's what a guy responded with to all this on another board .. if you can waid through it .. reMARKably thorough! :
-------------------------------------------------
"Keep in mind that my original schooling was in radio communications. I'm a bit of a heretic when it comes to this EMF stuff. But what I'm going to tell you is based on actual science and real world experience in an industrial setting where noise is a huge problem, not what's written on the back of a cereal box. I totally disagree with 99% of the recommendations out there specifically because the well meaning people that write those recommendations have never actually worked with and solved EMI problems, or even understand it. I'm going to praise Allen Bradley further down in this post but their specific recommendations on how to wire up some of their network cabling is terribly wrong. I've solved more than a handful of noise problems simply by having electricians ignore Allen Bradley's book and wiring communication cables the right way. I've been lampooned for it multiple times even after I got a system up and running which was broken down beforehand.EMI is very easy to explain. Our perfect world of "insulators and conductors" is utterly naive. Electrical signals generally travel along the skin or outer edge of wiring. The impedance of space, whether filled with air or not, is roughly 277 ohms, far lower than most folks expect. Since electricity follows the path of least resistance, it takes very little effort to launch a signal out into space in reality. And if there's a nearby receiving wire, err, antenna, then it takes very little effort to pick up that signal again. Any open, dangling wires with no connections on them are effectively antennas which pick up electrical fields. Any loops of wire are also antennas which pick up magnetic fields. So your "complete electrical circuit" that every book shows as electricity 101 has a serious problem with it...it's a loop, and it is very effective at launching electrical signals out into space. This very damning situation though is helped by that least resistance rule...electricity follows the path of least resistance. So as long as you don't have high resistance paths, you can keep electrical noise at bay in most situations.Communication circuits get a little different. In normal power wiring, the goal is to keep the resistance down right close to zero. In a communication circuit, as the frequencies go up, the wire tends to act more and more like a resistor (actually, an RLC circuit but we're staying with the simple concept here). It is very important to match that resistance as closely as possible at the transmitter and the receiver if you want to extract the maximum signal power out of the cable. Getting as close to "zero" resistance is no longer a good thing. So you are going to have to operate closer to the magic "277 ohm" number. The path of "least resistance" is no longer hundreds of times lower in resistance than space. So communication cables tend to be susceptible to interference.The easiest way to avoid this is to use different frequencies from the ones generating the noise. That's how Ethernet handily avoids power signals. It's also why fiber optic cables are "totally immune" to noise. They're not really immune. It's just that very few things out there other than the sun are generating interference in the range of several Terahertz. And it is fairly easy to create a wave guide or coaxial cable for light (fiber optic cable), as well as to add a nice, thick shield to the outside. Copper cables operate much closer to the less-than-perfect world, so we have to make do with living in the non-ideal world of fiber.In addition to the rule about the path of least resistance, if you think about it for a minute, that electrical signal is travelling out into space in roughly the shape of a perfect sphere before it hits your undesirable conductor. The amount of energy in the signal is fixed, even though the AREA is expanding as you get further away. So the received signal strength is proportional to the old high school geometry formula for a sphere, or PI*4/3*R^2, so the signal strength drops off with the square of the distance. If you are looking at a long straight wire, it's not a sphere but acts just like an infinite line of little spheres all along the length of the wire, all following the rule that the signal strength drops off with the square of the distance.99% of the "rules" out there deal with only this last consideration. They don't mention loop antennas or impedance or shielding or anything else. They simply talk about distance and stop right there.Finally, shielding is also easy to understand. Remember the rule that "opposites attract"? Well, imagine for a minute that you have a perfect metal sphere. Put a small negative charge in the center of that sphere. What happens? Well, electrons are repelled away from the inside surface of the sphere. The inner surface of the sphere becomes negatively charged, and the amount of charge is exactly equal to the positive charge in the center. Since the two charges 100% cancel out, there is no electrical field on the outside of the sphere. IF the charge is moved outside the sphere, then there will be a charge on the outside of the sphere and the inside has ZERO net electrical charge on it. If the sphere is stretched out of shape, the same rules apply. If it is stretched out, it eventually becomes a coaxial or shielded cable. Coaxial cable is immune to interference by definition. The only place this definition breaks down is if the shield is grounded at both ends (it becomes a loop antenna) or if the ends are poorly terminated, pins are bent, or the cable gets kinked. Coaxial cable works well where nothing else works, but it is expensive relatively speaking, and tougher to work with than 12-2.With that little EMI lesson out of the way, the rest of this should be fairly obvious.You are asking for specific recommendations. That's the evil of EMI (electromagnetic interference). It is very easy to measure it in a given system. The way that you reduce it (no such thing as eliminating it) is also pretty easy to understand. It is a matter of keeping lines separated as much as possible, using grounded shields when necessary, and crossing at right angles when necessary. This tells you how to reduce it but not what specific requirements there are. I can show you industrial literature that says that you should run communication cable at least 4 feet apart from power cabling, and run it in rigid metal conduit. A previous poster said that the rule is 16", and I believe you quoted a rule of 2". Utilities are even worse and say that 10 feet is the minimum. Who is right, and who is wrong? It depends on the voltages, the specific geometry, and especially the currents involved. It also depends on the impedances of the receivers on the ends (intentional or otherwise). There are no hard and fast rules with EMI because of the fact that every situation is different. I can tell you one thing is for sure...when you have EMI, it is usually obvious what you need to do about it. But it is hard to design for it ahead of time. In practice I usually just ignore it and then take steps to fix it after the fact.It turns out that the "cut-and-try" method is actually how EMI is done in the "real world". Electromagnetic engineers are a strange lot. Yes, there are lots of calculus equations that handle any situation. However, those equations only work with relatively simple geometric problems. In the real world, electromagnetic engineers usually rely on trial and error...they build something and test it, then modify and test again. When I was in college in my very first electromagnetics class, this is the first thing they taught us on the first day! To a man, the whole lot never relies on the complicated math that their lives depend on. So if these are the experts and they don't have any hard-and-fast rules, that should indicate why there is a problem. So we spent the whole semester memorizing and using equations that real electromagnetic engineers never actually use!In theory, with what you are trying to do and what you are using, it doesn't matter. In practice, nothing in this world is perfect. I wouldn't worry about it in the slightest though given the type of cabling and the signals that you are working with. If you have an interference problem, it will be obvious and you'll have to fix it. But anyone who tells you to do XYZ and you'll never have a problem is wrong. Unless you run every single signal in bonded rigid metal conduit, and all signals run in shielded cabling which is grounded at one end only, and the conduits are spaced at least 10 feet apart (using the substation rule of thumb). Of course even with this extreme rule, someone else can come along with an actual real-world example and prove just how dumb I am, and that I'm totally wrong, too. That's the nature of interference.By way of example, one of the most well respected electrical controls companies is Allen Bradley. They only recently jumped on the bandwagon of using Ethernet for industrial control. When Allen Bradley does it, they try to take the time to do it right. About 5 years ago, they were looking to give specific recommendations for running Ethernet cable in an industrial environment so they ran several experiments. For instance, they ran an Ethernet cable laying directly on top of a 600 Ampere VFD power cable for several hundred feet. They also took a CAT 5E cable and wound it several times up, down, and around a robot welding arm. Both of these are of course suicidal if you believe the recommendations about noise. However, try as they might, they were not able to achieve any signal degradation or errors at all for Ethernet! Strike one for EMI even in "bad" situations which all the books out there tell you to never, never, never, ever do this.Interestingly enough, many companies also recommend using "STP" for industrial Ethernet which is a shielded version of standard CAT 5 cabling. STP cabling is essentially a requirement in Europe, because somehow it just seems like having a shield would be better in the long run. Nothing could be further from the truth in that setting (totally opposite from residential by the way). It decreases the interference from electrical fields but increases the interference from magnetic fields because the shield, especially if wired incorrectly, becomes a very good loop antenna. At least one of the books I have for industrial Ethernet also says to make sure to ground both ends of the shield, which makes a bad suggestion even worse than no shield at all. Magnetic fields are far more prevalent in industrial settings because of all the large motors present. So the recommendation to use shielded cable actually makes the problem worse instead of better!By the way, notice my comment about loop antennas. If you have shields, the rule is to connect them on ONE END ONLY to ground. Not connecting them is bad. Connecting them at both ends creates a large loop with the ground circuit forming the other half of the loop. This is a type of antenna and instead of keeping noise out of your communication circuits, it will actually amplify it! That's why UHF (ok, now "DTV") antennas often have one of those big "hoop" looking things on them. AM radios often have one too but it's wound around a ferrite rod to make the antenna physically smaller.Bonding (connecting the covers of all of your metal parts together) for power wiring is Code. It's also a very good idea from an interference point of view when discussing anything except transmission lines (cabling). Poor grounding and bonding is a source of a lot of issues for power and signals. It keeps the EMI that is generated by power systems at bay, and more importantly, in the event of a fault, it keeps people from getting electrocuted. So we try to do everything we can to drill bonding and grounding into electricians. When it comes to communications cable, electricians correctly identify that a wire is a wire, no matter what it looks like. Then they go ahead and do what they are trained to do, and ground/bond everything together willy nilly without any concern for the signals travelling down those wires. Then they see noise on their perfectly shielded systems and declare that shielding either doesn't make a difference (false) or helps but is not as perfect as claimed (closer to the truth). Now you can probably understand why this is a perfectly bad idea in this one situation, and why the shielding probably did not do any good at all.Again, remember too that the frequencies matter. Ethernet, cable or satellite TV is all well above the frequencies in a power cable. Things change though if we are talking about CCTV (surveillance cameras, NTSC or PAL), AC control signals, or telephone conversations. Ethernet, cable, and satellite ignore 60 Hz level signals anyways and filter them out at the receiver end. The filter isn't perfect but you have to have a heck of a strong signal to cause any problem at all.On the other hand, phone lines and AC control signals such as light switches are another matter entirely. Since these systems work on low frequencies, they are very much susceptible to interference, especially inductive pickup. Standard telephone lines are NOT twisted pairs and are also highly subject to interference of all kinds, no matter what the source. Same with AC control signals and any other "low frequency" equipment. I'm sure we've all heard bad examples of this when you end up on a phoneline with an annoying 60 Hz buzz that is so strong that it makes the other person sound like they are calling from the other side of the planet, in spite of the fact that the phone system is almost entirely digital these days.For these types of signals, all the traditional rules apply. You can shield them but shielding isn't always perfect either, but it doesn't hurt. Make sure that if you use it, you use it correctly. The best thing to do for these types of wiring is to keep power cabling and control/communication signals physically separate from each other.So yes, the code books and all that other stuff, which is mostly concerned with control signals and phone lines for instance, is certainly correct. That is what most homeowners would be concerned with anyway. It is outright false and incorrect when applied to cable TV and Ethernet communication (but again, there are probably situations where this is not true), but following all those rules won't hurt."
A few nits I'd pick, but essentially correct.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
The funny thing is, and I kid you not, BOTH my phone line and my cable line coming in from the pole on the street out front come on down the side of the house via the electrical line-drop. They are both attached to the side of it, AND the phone box is attached to the house just 5 inches to the side of the main panel on the other side of about a 1" thick basement wall siding. In other words there appears to have been NO effort made to keep these systems separate in any way. The phone line and cable running DIRECTLY along the outside of the MAIN line into the house from the street! In light of all this discussion that really seems pretty amazing to me
The next time a tech guy from the phone company comes to the house I'll have to remember to ask him about it.
A~
If you mean the metal power line mast, keep in mind that the steel conduit is an excellent shield against interference. If the power lines are inside the conduit there is very, very little electric field from them outside.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Most phone cable is twisted. That is the flaw in that long story. The old J/K wire they used inside wasn't twisted and some aerial drops aren't but if you were set up for more than one line they will be. The "flooded" underground cable is 3 pair twisted.
Actually, the flattened black phone lead-in I see commonly used ISN'T twisted.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
That is true. I just never see it anymore.
I see it every time I walk out in our back yard.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Re 2 wire untwisted phone drop
"I see it every time I walk out in our back yard."Is it giving you any trouble? It must have been good enough then huh?
As I have been saying all along, you can overthink this.We have been stringing untwisted phone wire around the house for 100 years any where it was easy and not giving a second thought. Now suddenly it is a problem?When 2 line phones and data came on the scene they started using twisted pair, as the telco had been doing on the poles for a century and the slight chance of a problem went to virtually zero.
If you can't hear ringing current from crosstalk in a 200 pair cable, you are not going to hear a 60hz hum in a twisted pair, no matter how you ran it.
Yeah, it runs about 50 feet, parallel to the power lines (which ARE twisted) and about 4 feet away.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
And, yes, twisted pair is mainly used by the phone company to prevent crosstalk between pairs in the same cable, not to reject external noise.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
What do you think crosstalk is? It is external noise to the pair in question
True, but, as I said, the concern is primarily with multiple pairs in intimate contact with each other. Crosstalk diminishes very rapidly with distance.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
(It is fascinating, though, to be driving along a rural road with old glass insulator phone lines and see the pairs get crossed every 1/4 mile or so.)
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
"It is fascinating, though, to be driving along a rural road with old glass insulator phone lines and see the pairs get crossed every 1/4 mile or so."Those are probably power lines.
That is twisted pair or twisted triplex. Same principle as the twisting in a CAT 5 except at 60hz the wave length is so long you get an effective twist at thousands of feet each.
You see the same thing on HV transmission lines. If it wasn't raining I would shoot you a picture of the twist across the river from me in a 250kv line.
Nope, not power lines -- I know the difference. Phone lines (and, in the case of lines along railroads, telegraph lines). Observe them sometime, when you get a chance.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
I have seen telegraph lines along the railroad tracks but phone lines are usually in big multipair cables from what I have seen. I suppose they twist their pairs for the same reason everyone else does..
Telegraph is a fairly much obsolete these days. I think western union stopped the telegram a while ago. Railroads are digital now.
You can still see open-air phone lines in some rural areas.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
And the railroad still use (or at least used, up to a few years ago) the old telegraph lines for signaling purposes.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
This is a picture of the 250kv power line with the twist in it. If you look you will see they all do it every half mile or so.http://gfretwell.com/electrical/HV%20line%20twist.jpg
Yeah, I've seen those occasionally, though they seem pretty rare -- have followed high-tension lines for miles with no twists.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Maybe it is just an FPL thing but they all have a twist here.
Crossovers are common on 3 phase lines. But most of them are more subtle.You must not have had Fife doing the "wave dance".Actually I think that this was covered in a later class. I don't remember if there was a separate power transmission class or if maybe this was in a general electromagnetics class.But I remember doing the calculations.If you don't have crossovers from time to time it becomes a single turn transformer and the inductance goes sky high.And the same with the phone lines. In case you not only do you have the increased series inductance, but also it would be the secondary for the POCO line "transformer".
.
William the Geezer, the sequel to Billy the Kid - Shoe
Never took power transmission -- went digital/electronic instead. Just took the basic transformers class from ... darn, can't remember his name but he was dept head.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
No options where I was there..
William the Geezer, the sequel to Billy the Kid - Shoe
Yeah, "Barney" was legendary, but I think he was gone about the time I got there.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Also, one should keep in mind that cable that is exposed to potential lightning strikes needs to be separated via lightning arrestors from the rest of the system.
The NEC requires primary protection in those cases, but I always bid secondary protection in addition to this. I've seen plenty of equipment damage when only primary protection was provided, but very little when secondary protection is properly installed.
Bob
For exterior connections, I use the gold ones. They are a bit more expensive, but the typical standard ones get corrupted and lose signal after a year or two.
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I know that I've surpassed my question limit on this thread. But if anyone 'out there' is still willing to respond, I believe this may be the very last question:
I got a 500 ft. spool of Quad-4 RG-6 last night at the big orange box store and have MOST of the holes drilled and will be stringing it all day into tonight. My question is, when I take the four lines to the rooftop, would it be ok simply to terminate them there behind a little access door so that they could be gotten ahold of and attached to ... OR should I coil each one with an additional 6 or 8 feet that can be pulled out to attach to the dish. In other words, do I have to supply the FULL run to the satellite dish itself (even though I don't know where exactly it would be.) or is bringing it to the roof and assuming that they can attach to it without any problem be ok. Does the run from the satellite to the 'panel' have to be 'unbroken'???
Thanks!
Every connector is a potential place for trouble, particularly those out in the weather. A splice in a coax ends up being 2 connectors and an interposer.
But IF I simply ran them to the roof he COULD take it from there . . . . . right?
The deal is, I have NO idea what he would see as the ideal place for attaching a dish. I don't want to run 4 wires up there and add 22 feet to the ends of each of them!
It's better to have the full run -- each splice costs you a bit in terms of noise and signal loss. But one splice isn't going to kill you.
And in this case you may need to cut the wire anyway. The cable should go through a grounding block
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near where it enters the structure, and it sounds like your "little access door" is that point.
Remember that when you splice, though, you want there to be no strain on the splice, and ideally the splice should be out of the weather.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
My tower rooftop has a little pony-wall running around 3 sides of the perimeter. ((Hey .. didju see the pics that I posted?)) It's only about 18" tall. It's hollow and handles some of the top floor venting from above insulation in the ceiling bays to the outside. I'm running the RG-6 up into that and simply terminating them there. I called the satellite company again today and the head guy there in charge of installations said that I definitely did NOT need to try to second guess where the satellite dish might go and run lines to it ... that that was the lineman's job .. and that running it to the rooftop was absolutely all that they needed -- distribution panel to rooftop. He also said that I only needed two to run up there even for the heaviest possible use and High Def. Said that 'recent advancements' assured that four lines were no longer necessary.
I'm not putting any hardware anywhere. Loose ends at the 'panel' and loose ends on the roof. They can attach things this way and that. I donno enough what I'm doin to try to move that far into their job!
Thanks -
((is that little picture you included a frog? it sorta looks like the money I could be saving if I switched to Geico!))
You might want to pull a ground wire up from the electrical panel.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
You might want to pull a ground wire up from the electrical panel.
===========================
Yeah? Izzat right? No one has mentioned that. Should I? All the way up to where the dish would be connected, or just to the panel???
Up there to your access panel, to provide a ground for the ground blocks that should be installed there.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
will do.
thanks!
WHen I built my first house -- 19 years ago -- I was very proud of how wise I was to run phone cable all over the place -- including hidden in places I could find it later in case I wanted to add a jack. THen wireless phones became ubiquitous.... I have a feeling that tv will someday be more like computer in terms of being able to be transmitted wirelessly throughout your house...
Yeah .. I actually thought a little about that too .. things are moving so fast now technologically. But I went ahead and ran the lines anyway. But I'll bet you're right.
> I have a feeling that tv will someday be more like computer in terms of being able to be transmitted wirelessly throughout your house...(Should we tell him?)
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Yeah My Replay TV would send shows on a wireless lan with no problems. I just don't do wireless. I am a wire guy ;-)
I didn't read absolutely every post (I'm trying out to be in Congress) but I always wondered if there was a method to test at this wiring to make sure it was good before the walls were buttoned up.
If it was plumbing I could see it being pressurized and waiting 24hours, or if power I could at least test for continuity maybe heat it up, etc. There always seems to be a chunk of defective wire, pipe, whatever, even though brand new.
Does something like that exist for coax and newer stuff? I ran some coax through the attic, drilled through the top plate (tad warm up there) and snaked it down to a kids room (this was not new work) in the stud bay of an interior wall and when I hooked it up to a TV I got perfect signals on all except two local channels.
Must be the wire (nothing holding it in the enclosed stud bay) but then again it could be the screw on connection/s or maybe it was the local channels changing over to all digital and the signal isn't full power yet. Strange just 2 come in with snow. I know I'm going to get a call when the kid comes back from college for a holiday and those two channels are screwed. (TV where coax was strung by provider is OK).
I didn't charge for this but even friends will call and say.....uhhhhhh...say....that cable........... Thanks, Tyr
They make cable testers that range from simple continuity checkers to complex signal generator/analysers. It's only money. If I was wiring I would have some kind of decent tester that did more than just say the wire isn't broken.
I have a tester for Cat5. It sends signals one at a time thru each line that are read by the receiver. The same tester has a port for a cable connection but I have never used it.You get out of life what you put into it......minus taxes.
Marv