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I’m getting ready to wire our new house. Should I start at the panel in the basement, laying main lines to junction boxes then to individual boxes.
Or should I set the individual boxes and run the wires back towards the panel? Nothing I’ve read seems to address this. Maybe it doesn’t make any difference. Any advice?
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Unless you have a truly huge house, use a single breaker panel ("load distribution center"). Sounds like you haven't done a lot of wiring. Keep it simple.
Get all your boxes installed so you see what you're aiming for. Run 12 gauge out to each circuit (except, obviously, for the range, water heater, or electric dryer). I always start at the panel.
Most breakers can handle two wires under the terminal but no more. So you can't run all the outlets back to the breaker panel (unless you make lots of wire nut connections in the breaker panel - legal but a mess). Run a single romex to the closest junction box and go from there. Either use spec grade outlets ($3.50 to $4.50 each) to make the junctions or pigtail in each box. DO NOT use the $0.39 receptacles with the spring steel push-to-connect terminals. They are junk and will only take 14-gauge.
Back at the breaker panel, label each outgoing romex, in the breaker panel as you run it with a fine-tipped laundry marker and leave an extra foot or two (i.e. $0.02 of wire). After running all the romex, spend a pleasant afternoon making all the connections to the breakers, neutral bus, and ground bus in a neat fashion.
Drill big holes (1" in 2x4's, 1-1/2" in 2x6's - although 2" is allowed). Drill all those holes first so you don't have to work around the wires later.
Get the new wire strippers that cleanly strip the sheath off of 12-gauge romex (by Klein?) for $13. They make the work in the panel and boxes much easier and neater. -David
*David, I thought it was against code to:1. Have more than one conductor under the terminal of a breaker.2. Make wire nut connections in a service panel.If I'm wrong, please set me straight.
*In todays world, electrical work should be done by a licensed electrician. He gets a permit, and gets an inspection. If he's at all competent, you don't have to worry about burning down the house. Save money by doing the carpentry and painting, bad wordworking won't kill you.
*I agree with Jim W. I'm no electrical genius but if you are asking these type of questions hire an electrician.
*>>Most breakers can handle two wires under the terminal but no more. There's only one brand I'm aware of that allows multiple taps; most manufacturers don't allow it.It's particularly risky to use 2 different guages (12 & 14) in a multiple tap, depending on the type of connection.Different jurisdictions have different rules about splices in the main panel.As to how to do it: if you have a good plan, I don't think it would make any difference, although I suspect I'd try to be consistent with "outwards" or "inwards"
*I meant to add: try to keep it neat (big file attached):
*Dave T, Those new wire strippers (by Klein) are the cat's meow, eh? They make 'em in both 12 & 14 ga and also in a 12 & 14 combined. Best thing since sliced bread....Sam
*Arvid....I have wire spools on every floor and pull in run it in either direction. Many times, I will string my outlets together, then run back to the main panel leaving the wires out of the main and very long. Magic marker boxes and jackets...I also have a code that tells me what wire is what after the drywall is up. When pulling wire, it is easy to ruin wire if ya yank it when it isn't pulling easy. All your bends need to be radiused...There are many things to do right verses wrong. Too many wires in a group...Too close to the edgs of studs...running wire on top of wire...all are wrong. Oh and ya don't need the most expensive receptacles, but do buy up at least one grade and always use the screws, not the push in. Most home use devices come with both options.near the stream thinking you need a local mentor,aj
*AJ mentions wire spools. Make sure you are using them - you will find yourself very frustrated if you are trying to make runs pulling wire right out of a box. Also note his idea regarding having a code. You will be amazed how little you remember about things once the drywall is in place, just labeling without some type of code or map can also lead to frustration. And I'd vote against putting two wires on a breaker (even if code and mfgr allow it). It was done in my box and just contributed to making a mess that I'm still straightening out.
*Never run two wires to a breaker....And wire nuts do not belong in main panels either...but I have added to a wires length in a remodel once or twice in my life...But never in new work!near the e stream,aj
*> Those new wire strippers (by Klein) are the cat's meow, eh? Big believer in wire strippers, after run to emergency room while stripping insulation with pocket knife (outlet box in awkward location, startled by loud noise, knife goes into fleshy part of hand, 6 stitches). The strippers are another one of those tools that once you have them, you wonder how you ever lived without them.
*Rich and AJ: I'm quoting now from a breaker in my own house (Square D, Type HOM), "1 #8-#14 AWG Al/Cu 2 #10-#14 AWG Cu". So as long as you're using copper wire (I sure hope!), this brand allows 2 conductors. There are two distinct slots for wires on each side of the screw. The plate that gets tightened down is actually more flat and even with two than with one conductor. Other brands may very well be different. Your mileage may differ. I've been using Square D HOM style because they are widely available and really cheap if bought at HD with a selection of breakers all in one kit.Certainly those breakers in which the screw bares directly on the wire which is contained in a little metal pentagon should only have one wire in them. A second wire can easily not get enough pressure on it to make a good connection.Regarding wire nuts in a distribution center, I've always treated it as any other junction box, although 99% of the time I've left myself enough wire. No one has ever complained, but I can't quote chapter and verse on that.Sam: Yes, those specialized romex strippers are great. I first got the 12/14 combo, but then realized I never used the #14 sheath strippers, just the #14 wire strippers for the occasional 14-3 run to 3-way switches. So now I use the more compact #12 model.Barry: I less I use my razor knife, the fewer stitches I get. Hence, I have a lot of scissors, snippers, etc. Each of which does its job better than the old Stanley.I agree with AJ that you don't have to use the $4 receptacles. The $1.25 ones with screw terminals are okay if it is somebody else's house. But I thought this was his own house. As far as I go (short of a hospital or haz-waste site) is the $4 ones, not the $10-20 receptacles. Again, never use the spring steel push-to-connect terminals on any receptacle.Jim: "In todays world, electrical work should be done by a licensed electrician." I beg to differ. I agree that a DIY'er ought to learn and practice before wiring a whole house, but any regular poster here can run a new circuit just fine. I pull permits and I get inspections whether it is plumbing or electric or framing. "Specialization is for insects" -Robert Heinlein.To elaborate on AJ and Paul's idea of a code to wires into boxes: Something like 1) power in is always lower left, 2) power continues on out the lower right, 3) switched light is always upper right, etc. This saves having to write so many notes inside each J-box. Get one of those non-contact voltage "sniffers" for $10. If you don't label things perfectly, it really speeds up tracing circuits. Also a good double check that you've turned the breaker off before doing work. -David
*David....I am glad ya can wire guy...and I want an invite to hang out in Alaska soon!As to your comeback post...good thoughts....But do not encourage on the net to use wire nuts in the main panel or to have more than one wire to each breaker...Electricians know that the breaker is designed with a spot for wire left and right of the screw but that's not the point. The point is to run one wire to one breaker.Like tennis...there are many unwritten "rules" of acceptability...And neatness is one of the first noticed. Simplicity is a close second.near the e stream,ajAnd overdoing things is just as bad as underdoing...No 20a breakers in bedroom circuits...You can use 14 or 12 wire...but the breaker should be a 15. Don't run the gfi in the cellar with one four miles away in the kitchen...The next homeowners will never be able to find the tripped gfi that stopped the coffee maker...so much more to it...
*Barry...I wonder how you live in the presence of knives....maybe a set of kelvar gloves and a surgeon on standby from now on...Wait till you strip and wire your first accidentally 220v live wire...have your widow post a the pics of your burns...near kids playing with fire...aj (Mr love and kisses)OK beers on me...time to lighten up!
*AJ: I can see your point on simplicity. If someone has run two wires from a breaker and then someone else is tracing the circuit while hot, it could be confusing. The mystery would be solved by taking the panel off the load center, but it might not occur to everyone.I think the only time I've ever run two wires to a breaker is when I'm hanging a convenience outlet off the load center. For the most part, breakers are just too cheap to not use a mess of them (while leaving 4 or 6 empties for the future).What's your concern about 20-amp curcuits in bedrooms? Not as much protection against overloaded circuits? The only 15-amp circuits in my house are for the smoke detectors and a couple of lighting circuits (12-3 gets unwieldy). My thought is that you never know whose gonna plug in a 15 amp electric heater or hair dryer on a circuit that has a few lights going. And a bedroom might later become a home office with computer, monitor, fax, and xerox. Of course you could run 12 gauge in 15-amp breakers and only upsize the breakers that proved to trip often.Come on up sometime. We get pretty busy with houseghuests in the summer, but the garage loft is heated and insulated, and has a great view: http://www.alaska.net/~dthomas/ournewhouse.html -David
*Mr. love & kisses, Get those (wire) strippers we be talkin' about. They damn sure don't start fires. Don't know what you'll use 'em for on the court but you'll figger' sumthin' out. Maybe you can use 'em out on the slopes. Your buddy, Sam
*I have three pairs and probably fifteen pairs of sidecutters...I gots tools....Wired at least a dozen homes...Last big one was over 6000sqft addition.tools...I scared myself once ten years ago when my Quickin said I had over hundred grand in tools...Must be twice that now...Tools on Sale...near the stream,aj
*'Jack,The funny thing is, the attitude that, "it's only a little pocket knife, I can't get hurt much" is what probably did me in. I even remember thinking "if I slip right now, I might get naileed, wish I had installed these receptacles before the base cabinets were installed". If I had been using the same care as I do when using the chainsaw, I would have been OK.
*As to the question of whether to run everything from the service entrance panel or have sub panels -- do you have a multi-story house? If so, it'll save a whole lot of climbing if you give each floor its own sub panel. When the residents later trip a breaker, they'll find it on the same floor they're on, which is safer than having to climb stairs in the dark.If you're using conduit, get someone to push the wires in while you pull on the far end -- it goes a lot easier.-- J.S.
*As I said in my earlier post I'm no electrical genius. I make most of my living painting and rocking. But I still agree with Jim W. and hire an electrician. My sister in law had an electrical fire in her house started from an outlet that her good ol boy friend put in and screwed up. You know what she got from her home owners insurance? El zipo. Nothing. Nada. The inspector cited "unlicensed electrical work". To suggest that just because someone posts here should wire a whole house is pure folly. I'm not saying one is not capable of doing it, just shouldn't do it.
*Beside running and stapling Romex from panels to boxes, there are many other details that are subject to strict coding. For example, when your run more than 3 conductors in a conduit, the ampacity of each wire is subject to derating, the more the wires, the more the derating. Temperature affect the rating of wires as well, so before you run your lines in your 140 degree attic space, check your tables for you might be in for a surprise. Panel clearance, number of conductors per box size, stapling schedule, etc... all those things add up and someone has to account for them. Many people claim electrical work is simple, I say electrical work is systematic but far from simple. If you are not so sure about your abilities, I suggest you get someone with knowledge to help you with it.fv
*I'm with Francis - electrical work is not simple but is systematic and, to many, eventually pretty straightforward.Carl: Are you trying to piss me off? I didn't say, "just because someone posts here should wire a whole house" so don't misquote me. Can you name a regular poster here (AJ, Gabe, JoeH, BobW, FredB, JoeF, RyanC, GACC Dallas, FrancisV, FrankD, PeteD, ArtB, etc) that couldn't run a new circuit? Sorry your family doesn't read contracts and policies before signing them and then does crappy work, but don't comdemn all non-electricians for the mistakes of your wife's sister's boyfriend (who also sounds like "no electrical genius"). The obvious reaction to that could be to suggest everyone hire a lawyer for any contract or insurance policy they enter into. Some need to. Some don't.Maybe it's a regional thing. A lot of people up here can build a house, build a boat, build a plane, butcher a moose, smoke salmon, fell, buck and split a cord of spruce, fix their car, mush dogs, and/or design a website. I haven't done the plane or moose. Yet. And I won't be using an A&P mechanic or union butcher when I do.
*Dave T., Sorry I quoted you wrong. I'm not trying to piss you off. I read several posts in a row and was going on memory after a long work day. You did say that a regular poster could run a new circuit. You did not say one could wire a whole house. (It was in the same sentence that you said a DIY'er should learn and practice before wiring a whole house. Hence my misquote) I have been to Alaska twice and yes there are regional differences. The people in Alaska (at least that I met) are more self-sufficient when it comes to doing mechanical things. It comes with the territory I guess. Yes my sister-in-law's ex-boy friend was an idiot in more ways than one. No one in the family really liked the guy. Used drugs and was a lazy moocher. He did not do crappy work he didn't work at all. He was never part of my family. As far as not reading contracts before signing them goes, I do not think my sister-in-law or most other people read every little line in their insurance policies. Car, home owner's or whatever. I have looked over mine and it is filled with legal jargon and BS. I understand the basics and move on when it comes to those things. I don't think I'm alone in that. All I know about her fire and subsequent problems is that the insurace agent (according to my sister-in-law) stuck the scorched outlet under her nose and asked who installed this? Mayby it's a New York City thing but all I'm saying is she got stiffed. She's a song writer and a musician. Not a jack of all trades. She wouldn't know a paint brush from a motor brush. My reccomendation to Arvid P. is to hire an electrician. It just comes from my experience.
*David, Thanks for your time and advise. I like your idea of making big holes (should keep the heat factor down) and drilling them all first. I don't expect to have to use more than one line per breaker. Might be confusing also. Trying to keep it simple. We'll go with the spec grade outlets, but one question . . . Which type of boxes to use; plastic or metal?
*Bob W., Great pic! I printed it off and I'm going to post it up next to the new panel as an example to follow. Consistency and neatness. This is new construction so there is no need to splice in the panel (or anywhere). Thanks for helping.
*Barry: My wife and I have been building this ourselves, so I've already anointed it with enough of my blood. My wife calls it offerings to the house building god. So far nothing serious.
*Jack: Thanks for the advice. Another great time and back saving tip. We'll put spoools on each floor. Good idea on the "code" also. We take lots of photos but the code will help also. I'll radius the wire where it bends. Thanks again. One question regarding not running wire on top of wire. . . you saying only one wire should be under each staple? Sounds sensible though.
*John:Thanks for the help. I'm glad you mentioned sub-panels. This is a multi story building with a 10' basement and 1st floor. The 2nd floor has the option of being a separate living area. I'll check with my inspector on sub panels.
*The NEC warns against using two cables on their edge, side by side under one staple. I couldn't find anything regarding 2 cables on top of each other under one staple. I don't generally do it, but I see it constantly done and it doesn't seem to alarm any inspector.fv
*Arvid, as far as the 2nd story of your house is concerned, you would be better off with a subpanel up there for the sheer convenience, since it could potentially become a separate dwelling, and for the sake of not having to go up and down the stairs to reset breakers. Mind you, if you plan on renting the space, you might be in for a separate service. In the mean time, a 50A breaker to a subpanel upstairs via 6/3 Romex would be one way to go. If it is to become a separate living space, you might have to go 60A with #4 Romex or #6 THHN in a conduit.fv
*Thank each one of you for responding. This is without a doubt the best web site on the net! This house we are building is small (2400 sq ft) but very tall. Except for pouring the basement, my wife and I have put every nail and screw in it so far. We built a smaller one for ourselves a few years ago where we live now. Ran all the electrical here also. Our inspectors here are very helpful. We'll be inspected with everything open. Since we don't pay labor we don't need to take short cuts to save costs. I certainly don't recommend this (DYI) to everyone but it fits our lifestyle and we don't get frustrated dealing with contractors or laborers who don't show up or do shoddy work. I'd still like to know whether metal boxes are better than plastic.
*Wow Frank! You are right on this. You read my mind. That is just what I needed to know. #4/3 Romex with a 60A breaker. I'm on my way to the local supply store now.
*If I were to wire my own house, I would use metal boxes everywhere. They are strong, they clamp your wires very nicely, and your switches and receptacles have something to grab on. But, since we use non-metallic cable these days, the purpose of the metal box is gone since there is no metal conduit between boxes to carry the ground and be used as an interference shield. I still would use the metal boxes though, and run flex to some specific areas such as a recording room for the musician, or to a computer room, etc...You will need to put a green pigtail in each box though. It's more work, more money, but it's definitely positive.fvfv
*One last thing, separate ground and neutral buses for subpanels.fv
*Carl: Thanks for the explanation. Sorry if I got all fired up - not allowing people to develop and practice most any skill that want always sets me off - I thought that's what you were implying.We agree that contracts should be in plain English. I'd pay a bit more in premiums to be able to scan a policy quickly. As it is, I make the agent wait while I wade through it cause I won't sign till I do. Amazing how many are unable to answer any questions that arise. In car insurance, one often knows enough people who've filed claims to get a sense of what companies are willing to make good (AAA in my experience) versus those that only collect payments and stonewall on claims. Safeco quickly paid for a roof repair in my Seattle rental. Who shafted your sister-in-law? Spread the word.Arvid: As Frank points out, metal boxes must be grounded. Assuming that, like 96% of the country, you're allowed to use romex instead of metal conduit, then you'll have to run a pigtail and tie the box to the bare ground wire of the romex. I use metal boxes when it needs to take some weight (big light fixtures) or if I need more volume and need the metal boxes with extensions. Definitely also for ceiling fans, but look for the 35- or 50-pound rating on the special metal boxes. For standard outlets, I use the biggest plastic boxes (like 22 cubic inches) I can find - they are bigger than most all metal boxes and that makes all the later steps much easier. Don't buy on price ($0.19 to $1.25 for single gang, nail-up), just get the largest volume one. 22 cubic inches has a lot more room to work than 18 cubic inches. Doesn't seem like it would, but it's true. About big holes: Implicit in the measurements I gave is the requirement of leaving some minimum amount of wood, but to be explicit: If you don't have 1-1/4 of wood between the face of the stud and the hole, you must put a nail-protection plate over the area so the drywaller and sheathers can't reach the wires with their nails and screws. -David
*I have a mishmash of wires staped all over the place so I just noticed a new product 3M has at Home Depot that meets code, and allows stacking 4 #12 with each nailed in plastic thingy. I would think it could come in most handy as you start heading into the main panel.I have some metal because house has some bx, and I had been putting in cheapest plastic as I added things. Someone here mentioned using fiberglass ones instead of plastic, and I would concur with that. The plastic ones are too willing to reshape themselves as you are adding sheetrock, the fiberglass are as sturdy as metal in my opinion.And I think somewhere in this thread, someone mentioned getting a stripper for the outer cover of Romex. They are $13 at HD or Lowes, and I'm glad I bought one, much easier to use than that little tool with the v that I suspect a lot of us have used when not using the razor or pocket knife approach. For the amount of covering you will be stripping, it will be $13 well spent.
*Arvid,Three books i would strongly suggest that you read: (1)WIRING A HOUSE by Rex Cauldwell (a Taunton book....$34.95....but worth every penny)(2)CODE CHECK - ELECTRICAL (also by Taunton...not sure of the price)(3)ADVANCED HOME WIRING (by Black & Decker...I think I bought mine at Home Depot)Read them all cover to cover before you start...then READ THEM again!!! Thats what I did before I started the wiring on my cabin. Passed the buidling inspection on the first round with no major findings.Adam
*Just 2 additions. If you are contemplating renting out the top floor, a second service meter could save a lot of hassles when it comes to utility bills for a renter. It's a little more up front that could save you a lot later on. And do work neatly and with good labels at the box, as in the previous photo. Labels on the wires and the breaker make reconnections later much simpler, when the kids decide the old place needs an upgrade. Good luck, you have some great help here.
*Adam,Thanks for the tips on books. We are book people here. We've got the Cauldwell book and the Advanced Home Wiring. We'll order that Code Check. We also have Electrical Wiring Residential by Ray Muslin from Delmar Publishers. Got it for $59.95 through the JLC site. It seems to cover all the technical and theoretical aspects. Yet it presents the material in a understandable way while citing and reprinting the relevant NEC requirements.
*Bill,My wife agrees with you on the second meter. We'll separate the wiring for each floor. I've already gotten a 100A sub panel for the second floor after reading Frank's post. But now I'm thinking we'll use a sub panel on the first floor as well. I'm holding off on the second meter at this time, but will try to wire so one can be added later.
*David,Thanks again. We got the biggest plastic boxes they had at HD for the wall outlets and switches, (the Cauldwell book also recommends using the largest size box) We'll get the metal ceiling fan setups for the ceiling fixtures just in case someone wants to put them in later. We got the Milwakee right angle drill along with 1" and 1 1/4" auger bits. Will just drill two holes where we need them instead of one big one. Thanks for the tip on the nail protectors. We may need them on the 2x4 interior walls.
*Paul,We were at HD yesterday to pick up the sub panel, boxes, etc and were directed to those plastic wire stacking thingies, got a couple packs. Got those strippers too. They work great. Why'd it take them so long to invent them? Thanks.
*Arvid, since you and your wife are book people, you could pick up an NEC manual as well. The 2002 issue is available. On the issue of a separate service, you will need to go at least a whole 100A, so you might as well cable up to your subpanel with the appropriate wire gauge (#1 THHN) in a conduit, and leave enough slack to connect to a separate meter when the time comes. That #4/3 Romex will come in handy for another subpanel. The NEC indicates that the minimum requirement for a one family dwelling be 100A. Check with your inspector.fv
*Speaking of little plastic thingies, don't bother with the metal romex staples. Get the white plastic straps with a small nail on each end. So much easier to put in and so much easier on your fingers to not get bashed with hammer. They cost like $0.03 each instead of $0.006 for the metal staples but you only need $15-20 worth to do the whole house. My fingers are worth it. It makes stapling romex almost pleasant instead of tedious. -David
*The best tip for wiring that I found after completing my house was to run 14/3 to the outlets in each room, with 1 side of the 14/3 switched. At any time in the future you can have a switched outlet anywhere in the room by connecting it to the switched feed instead of the always on.
*Arvid,I just caught this thread.You were asking about metal vs. plastic.When I wired my addition I used metal 4" boxes with a mud ring. Lots of room for connections and easy to expand if you find a need for another outlet in that same location later.And as KJ said above you might want to consider 12/3 since and a switch by the door. It allows for a switched outlet anywhere in the room.Scott
*AJ, Are you still here? You wrote that it's bad to put bedrooms on a 20 amp breaker...Could you provide a little more about that? What is the reason? Thanks
*Receptacles in bedrooms are thought of as lighting circuits. That said, a 15a breaker is closer to protecting the wire sizes of plugged in devices....near the stream,ajWiring in 12 wire is fine...just still use 15a breakers...unless you start running air compressers and tablesaws from your bed. Hair dryers work fine on 15a breakers.
*Frank: Thanks for noting the important part of disconnecting the neutral and ground buses in the sub-panel. Didn't know what you meant at first. Its well explained in the Cauldwell book. I don't understand the theory yet but know its a must. We decided to go to #3 THHN with 1" plastic conduit to 100A sub panels following the example in the Muslin book.
*Frank: #1 THHN?!!! I thought going from your original suggestion of #6 THHN to #3 THHN would handle it. I can see you're a no compromise kind of guy. You're probably right though. Wife has plans for a dish washer, (along with usual kitchen appliances) and spa tub on the second floor and hot tub on the roof (all on that second floor sub panel). I'm thinking I'll use the 100A sub panel and #3 THHN, I've already bought, on the first floor. I might as well put a full 200A sub panel on the second floor and use the #1 THHN in 1 1/4 conduit.
*David: Thanks for the tip on the non-metalic staples. We got a few packs. They look a lot safer. Glad to hear they hammer in easier also.
*KJ: Thinking about your swtiched recepticals idea. What uses, other than lighting, do you have in mind?
*My main idea was lighting, but I will kick myself again if someone has other uses.
*Arvid, I meant #2 THHN, good for 130A. I had to use #1 for 3 subpanels in a school, but that was a State job and the voltage drop had to be negligeable. #3 would be ok too at 110A, but I don't like to keep it too close. Sorry about the error.fv
*By the way Arvid, #1 THHN copper is rated at 150A. For 200A, you'll need 3/0. Maybe it's time to scale down back to 100A with the #3 for your upstairs. 100A is probably all you'll need. My shop runs just fine from a 100A subpanel.fv
*Bedroom guys, come back...I just read in JLC that arc-fault circuit interrupters will be required in bedrooms in 15 and 20 amp ratings for 75-125 DOLLARS EACH.Is arcing commmon in bedrooms to warrant this outlay of money? Why won't it be required in other rooms? How is this going to be safer than a regular GFCI? Doesn't the breaker take care of the short? Is it one per bedroom or can multiple rooms be on a single AFCI?In layperson's terms, if you please--i only play an electrician in my mind. If anyone knows the reasoning/history to this code change...TIA.Off to buy more books...
*splintergroupieMy understanding is arc-fault is required in rooms where people sleep because of concerns of fires starting from frayed wires in reading lamps and other such electrical items that are used in bedrooms (and are left on for extended periods).Evidently a regular circuit breaker will not detect certain faults in wires that could cause long-term overheating and resulting fires.I nearly had a heart attack when I found out how much Square D's version is - thought they were going to have to be all breakers.
*Frank:Just got off the phone with the inspector. He would have let me run #6THHN in conduit to a 100A subpanel. But he says my 1" non-metalic conduit is too small for 4 #3THHN wires. I'll need to go to 1 1/4" conduit (see NEC table C-2). Also, of interest: he does not like pig tailed grounds in wall boxes, suggests pulling 12" of romex out one side of the box and 6" out the other, strip the cables, cut the neutral and black to 6", leave the ground long and crimp the grounds together so the crimp is at least 3" out of the box, attach long ground to device. Leaves the 6" cut-off neutral and black wires for pig-tails for that box.
*Arvid, the reason why your inspector doesn't like the ground pigtail is because he doesn't like to see 4 ground wires on a nut. It's a matter of preference. I did commercial electrical in San Francisco and I had to have a green pigtail in every box. You omitted to mention that the short leg of the ground gets connected to the box while the long one goes to the device. I like the fact that you are left with the black and white pigtails, it's efficient. Your inspector is right about the conduit size, and let me clarify this: It's ok to run #6/3 romex to a 100A subpanel but you'll have to use a 50A breaker, not a 60A one, and certainly not a 100A one! NM cable is rated at 60 degrees even though individually, each wire is rated at 90 degrees. While #6 THHN (90 deg.) is good for 75A, #6/3 Romex (60deg.) is rated at 55A.fv
*Ok, before I go bend some conduit, let's go over this. You are going for #6 THHN copper in a 1" conduit to a 100A rated subpanel for a total ampacity of 75A. You will of course use a breaker rated at no more than 75A, and no less than 60A (minimum service size for an apartment) in your main panel, am I right? If so, all is good. Just checking!fv
*> I'll need to go to 1 1/4" conduit (see NEC table C-2). Since you're doing this yourself, you might want to go a size larger than code requires, 1 1/2". The extra cost is small, and it makes pulling the wires easier. There are some combinations of wires and conduit that are allowed by the NEC, but which can be damn near impossible to actually physically make in the real world.-- J.S.
*Thanks for all the help folks. We are well into the project. Frank: We are straight on the wire and conduit. Thanks everyone. We be off the computer and on the job from now on.
*John, Arvid is using conduit for a short run. 3 #6 and 1 #10 (ground) stranded wires are not going to take more than 40% of the conduit space at 1" and will pull smoothly. Why go 1 1/2" conduit and have to drill 2" holes in your wall plates? I understand your concern on long underground lines when you wonder when that cable is going to snap...fv
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I'm getting ready to wire our new house. Should I start at the panel in the basement, laying main lines to junction boxes then to individual boxes.
Or should I set the individual boxes and run the wires back towards the panel? Nothing I've read seems to address this. Maybe it doesn't make any difference. Any advice?