I’ve got 750′ of buried aluminum (3 wires) to my shop, which also houses the pump electricals. 14 yrs old. Mid-shower last night I ran out of water. Turns out I’ve now got a 70 v. drop on one leg, starts at 123 v. and ends at 53 v. Other leg is fine. Direct burial, like the BI and elec. distributor recommended.
My well pump is not amused. Nor is DW.
Called all over today trying to find something/somebody who could find the fault, which is probably failed insulation (rock), causing the aluminum wire to decompose in wet ground.
The only somewhat helpful advice I got was from a rental place who offered me a wire locator, sends a signal down the wire and picked up on a receiver. Trick was to complete the break in the wire, by hooking a welder to both ends and blowing out the fault.
Somehow I can’t quite see doing that. With my luck I’d likely destroy down the whole thing. I’ve got it located within 600′ and have the backhoe ready for tomorrow unless somebody here knows how to find the fault. Copper got expensive when I wasn’t looking, but I suppose y’all know that. One lousy rock, grrrrrrrrr…..
Help?
PAHS Designer/Builder- Bury it!
Replies
There is a TDR (time domain reflectometer) that can help pinpoint faults.
But I doubt that will find one in a local rental shope.
Might try calling electricans to see if any have one.
BTW, the phone company "burns out" faults all the time. For the same reason to get eitehr a clear open or clear short that they can find. But I think that there cables are #22 or 24.
Bill's suggestion of using a TDR would do the trick.
I know you have a lot of machinery like me, maybe you have an oscilliscope with a 10 nanosecond sweep of faster?
If so, you can do a capacitor discharge and watch for the return pulse, about 1 foot per nanosecond, so 300 feet = 0.3 microsecondsx2 = 0.6us.
There is also a device the power companies use called a 'thumper' where you discharge a short high current spike onto the line -- rich man's version of just momentarily touching the welder and literally listening for 'thumps' in the ground where the arc is occuring.
Also, as I've (blush, where did that knot on my forehead come from) done the hard location thing only to find it was a bad connection at one end - double check connections if you have not done that already.
PS: You didn't say what gauge Al wire. I have graphs of the current from a welder different gauges can take prior to insulation damage. e.g even 16 AWG can take 230 A for short pulse without damage.
Edited 7/7/2006 10:48 pm ET by junkhound
Thanks guys. Already got more info here than 2 hrs on the phone yielded. I didn't know what to ask for and nobody would/could tell me. TDR, eh?
I spoke with large and small electrical contractors yesterday, including those recommended with the capacity for locating faults. One maybe had the equipment, he wouldn't say, would only say all his work was one month out. Got several offers to come out and splice when I found the fault.
Thought maybe the satellite TV/internet guys might have a locator, but my friend in the business said no. If a buried line develops a fault, they simply bury another.
Even my guy who's a wheel with one of the larger electrical distributors came up with nothing. Wasn't able to reach my U. employed electrician (has his own office and supervises a large crew). Both schedule their work years around deer hunting up here.
Junkhound, I've used an oscilloscope, about 40 yrs ago in vacuum tube days. Today, I could maybe figure out how to plug it in... One doesn't live here, although the auction I'd been thinking to attend today, it wouldn't be out of place. Guy had some of everything. Want a '56 5 ton army truck with dump? '54 D4 with winch?
McMaster Carr offers a couple of locators that might work, several hundred dollars of course, and I don't want to buy something that "might" work. Catalog's in the shop, but I don't remember seeing anything about TDR. One did say it would tell how far the problem was from the meter.
If I'm reading the jacket correctly, wire's #2. By the time I got a welder hooked in I'd have 1200' and wouldn't have any idea about amperage. I suppose you start small and work up until the signal stops at the blown open fault? Sure would like to find someone with a TDR...
First things I checked were end connections and splices. Found one small problem near a splice. Still correcting what a past employee did with a shovel while installing a water line check valve. Must have been a very small nick for it to have lasted so long. Was happy to see that my nearby buried splice was good after 8 yrs. PAHS Designer/Builder- Bury it!
If I were 2000 mi. closer would probably bid on that '54 D4 with winch.
It's just down the road and I won't be.
DW has been thinking about my upcoming Erie sailing and figures that maybe it's time to have some buried copper here. Not much chance of her hooking up the PTO generator and figuring how to get the well pump energized.
Looked at one online wire calculator which said my aluminum was a couple sizes too small. Never seemed to be a problem (not that I ever measured the voltage under high load). I've got several hundred feet of 6-6-6-10 copper in stock. Unlikely I'd find enough larger copper today, but there's always next week.
So when the laundry's finished I get the tractor back, re-install the hoe, and have at it. At least I don't have to worry about the water line freezing... Turns out the McMaster Carr testers aren't TDR.
Now, if I could just find a nice used water tower...PAHS Designer/Builder- Bury it!
check don mccarty's website at mccartyinc.com for how to do a resitance to fault locate. he is a specalist for telephone cable type troubles. basically you need a multimeter to read the resistance of your line without the electrical loads.
Edited 7/8/2006 1:58 pm ET by ottago
This is interesting. Thanks.
I've currently got the fault surface bypassed, know where it is within 300'. I found a bad-looking place near an old problem. Wasn't the current trouble, unfortunately, but a future one. Which tells me that I've likely got more problems.
Now thinking to either replace the wire (in conduit) or abandon by adding a new meter at an outbuilding. Will be talking with the elec. supplier Mon.
PAHS Designer/Builder- Bury it!
a new meter at an outbuilding WOW!!
Wish I could do that here, would jump at the chance, the first 600 kWh are 60% the price of everything over that. Obviously, Puget Sound Energy does not provide 2nd services.
"Wish I could do that here, would jump at the chance, the first 600 kWh are 60% the price of everything over that. Obviously, Puget Sound Energy does not provide 2nd services."Electric rates can be funny (strange).Here there is a base rate for the for first x amount (it might be 600kWhrs also, but don't really remember).Then furing the 4 "summer months" it goes up in two increments, about 20-30%.The other 8 months it goes down, about 50%.
Obviously, Puget Sound Energy does not provide 2nd services.
What do farmers do?
The last outbuilding I built (with the copper/translucent panel roof) was with a farm building permit. The only required inspection was from zoning, checking required setbacks (which I'm pretty sure never happened).
My elec. supplier, a coop, is very picky about what they're hooking into. County gave me a release, which requires the coop to add the meter in absence of electrical inspections. As it happens, theres an existing junction box 60' from the building in question. That's where the coop underground feed stopped, the end of their first 2000' roll.
Original installation was rather interesting, took the better part of 2 yrs to finalize. I'll see what their story is tomorrow. Placing no bets, hoe at ready. PAHS Designer/Builder- Bury it!
Now, if I could just find a nice used water tower...
watched them deconstruct (scrap) one last year - had a nice brass ball on the top, too - - the old manufacturing buildings downtown Wabash are just about gone - there's one more privately owned tower (not in use) that's a twin to the destroyed one - be difficult to get it to VA, it'd be a very oversized load -
my great uncle started and ran an orchard supply company, he was a wheeler-dealer - he supplied 20K gallon cylindrical tanks to many orchards thru IL and IN - salvaged deals out of Indy, I actually have some video of them erecting one and another snippet of them moving one of the tanks on a '30's era flat bed truck -
"there's enough for everyone"
there's one more privately owned tower (not in use) that's a twin to the destroyed one - be difficult to get it to VA, it'd be a very oversized load -
Not to mention that filling with a well producing 2 gpm might take awhile. LOL And up my driveway? Or.... seems like I remember somebody doing helicopter logging recently.
Naw... it'll have to be pretty small. Unlikely I'll ever come across one. But if it'll fit on my trailer I'm ready!
A buddy here bought a defunct orchard (no sign of the trees) with a small tank for gravity water, spring fed from the mountain. No idea how sound the tank is now, but he wants to keep it and redo the supply line. Waiting for me to visit this fall with my largest loader. We're gonna have some fun. He's also got a silted up pond.
Your uncle was my kinda guy.PAHS Designer/Builder- Bury it!
re:tanks -
I've been kinda looking for a milk hauler for myself - I'm not sure how many gallons a SS semi holds, but it'd be big enough for my needs - I believe there is some law about dented/damaged tanks not being used, there oughta be a few floating around - I just haven't really put a lot of effort into the hunt - other things higher on the priority list - View Image
here's one of uncle EA's spray tanks with a stationary spray station set beside it -
"there's enough for everyone"
Love the foundation under that tank...
Damaged milk hauler, eh? I bought a pull-behind road grader from a dairy guy. Probably have his number here somewhere. Interesting idea- if you get there before the scrap metal guys do. I was pleasantly surprised last time I sold steel, mostly old engines and rears.PAHS Designer/Builder- Bury it!
I haven't sold scrap in a long time, but the last time I was dealing with the yard, stainless had the least value of any -
uncle EA was based in 'Clay County' Indiana - several companies making various tile products - those big tile are 18" on a side with 9 channels thru them - long ones are heavy - still a few floating around and a number of building built from them in this area - - not sure what they were originally for, but EA bought all the seconds and sent them all over (for a profit) -
here's a pict of one of the buildings at the big orchard made from those tile, my cousin Jim is unloading some more seconds of a different tile that EA scored - the second pict is using those tile to build the big refidgerated storage -
sorry about the pict size - don't have time to resize right now - View Image
View Image
"there's enough for everyone"
Uncle EA, off to make his fortune -
View Image
"there's enough for everyone"
Didn't know that about stainless. Always segregated so I figured it was higher.
That tile looks like what my German sister's new house was built with. Pretty sure her daughter, having a house built currently, has the same thing. Nobody making them today? "Refrigerated storage" indicates they thought them pretty good insulation? There's a whole technology there I'm unfamiliar with.
Speaking of seconds, when living in Denver I used to visit a couple of guys in Ohio who bought rejected Rockwell castings and made fake Rockwell stationary tools. For several years I paid for my fishing visits by filling my cube van in Ohio and hauling woodworking tools to Denver for resale. Still have one of those almost-Rockwell lathes.
Your uncle was much more motivated than I am. Most of the (free) building material I drag home gets given away. Community service.
Thanks for the pix. Pretty interesting forklift. Not much good up here...PAHS Designer/Builder- Bury it!
dunno if those tile are still made - likely something similar is availible - if you'll look closely the cooler has a double wall with 6" of ground styrofoam between - not near enough by modern standards, but with surface applied foam on the inside, things would be fine -
I still have that forklift (actually there are two of them) fine for light duty - whadda collection of vintage jun... treasures -
"there's enough for everyone"
whadda collection of vintage jun... treasures -
I can relate. But I hadda buy all mine from strangers.
Awaiting pix from the new German house. Parents were here for a wedding recently, but daughter didn't get around to sending pix before they departed.PAHS Designer/Builder- Bury it!
Yeah, TDR is what you need. A cable TV guy might have one. Check with the guys who install specialized electronics in your area.
...." causing the aluminum wire to decompose in wet ground. "
I have had the pleasure of repairing some underground temps over the years, some of the easier ones to find were in the winter ......the ground would be muddy and steam would be visible, but those were usually 480v temps........
I won't suggest you try it , but I just wanted to pass my experiences along
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Steam? Pretty sure that's nothing I want to mess with.PAHS Designer/Builder- Bury it!
PG&E, they supply where I'm from, had the same problem with my service entry cable but it was only about 100 feet. They came out with all their tech equipment to locate cable and find the bad leg, marked up the concrete walk and drive and began digging. They found the break, it corroded cable from possible nick in the sheathing, and made the repairs. They ended up replacing the whole cable from underground transformer to my meter (up drop). I asked why they just didn't repair the broken splice and they said that if one portion was damaged then it was likely that there were other potential breaks that would require repair at some point, so they just replaced the whole thing.
I realize it's a lot of extra work but since you've got a back hoe, why not just trench in 3 inch conduit the whole distance and pull new cable? Actually a rental Bob Cat with trenching attachment would be the way to go. It's a sure fix for your problem, if you need to service at a later date all you need to do is pull out and repair it and the conduit will help protect the cable from accidental damage. Put in two or three "Christi" boxes along the way to ease future service needs and you've got a first class installation.
You're right. After digging up one spot and finding a problem near an existing splice, thinking I'd found the fault only to discover there was another, we concluded that new wire was the answer. If I lay it, it'll be in pvc this time.
A trencher would be faster than my hoe, but I've got a lot of buried cable and water lines. With the (small) hoe I can feel it before I break it. I'm looking at a day either way. Drive to town, trench, drive to town to return it. Or just spend about the same amount of time using what I already have.
The other choice is a new meter at the other end. I've already got a panel there and a coop junction box is nearby. The coop would want me to provide the trench, but that's no big deal. My question to them tomorrow is how much and when for the installation and what sort of bill do I get for non-residential. At least they no longer read the meter but once a yr. I can also get the current that I missed by not using sufficiently large wire.
Never dreamed I'd own such large stationary machinery. In Denver I ran my whole shop on 50A. Now that's insufficient and all I provided for here.
What's a "Christi" box? Even though I managed good buried splices, I'd be thinking pedestal next time. PAHS Designer/Builder- Bury it!
around here we call them Quazite boxes......I think its the same thing.they are a cast polymer-concrete product, for your application you would need only the open-bottomed type handhole .... for any splicing you may need to make.
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here's the mfr's link.....http://www.strongwell.com/PolymerConcrete/Quazite/Introduction.htm
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The generic name is handholes; ie, small manholes.
that's what I wrote......have you had the pleasure of drilling holes in one, what a treat.
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Thanks for the link. I used one once, supplied by my client for housing a water valve. I'd forgotten about them.PAHS Designer/Builder- Bury it!
A Christy box is just a concrete box in the ground that the electrical line, conduit, runs into. The conduit enters the box about 24 inches underground and then immediately leaves the box again in another conduit at the same depth. It's like pulling wire through metal tubing, every so often you need a place to pull wire that doesn't put a lot of strain on the cables or wires. A Christy box in the ground is just a protected box in the ground that allows access to the cables underground. Around here they're all made by a concrete company who's name is Christy, so everyone just says Christy box for short. I thought they were all over the US. We ran a electrical line to a house that we were building that was up hill and about 300 feet from power, lots of hand digging for a couple of weeks just to get the line installed ,with a lot of tight spaces and under big trees etc. We installed 3 inch NMC (PVC)conduit and after gluing it all together we had to pull what the power company calls a PIG through the line before they would pull cable. The pig was used to make sure that none of the turns in the line were too sharp and that there were no obstructions to the incoming cable.
When it comes time to pull the first string through the conduit, simply hook a shop vac to one end and apply the power to the vacuum. On the other end, tie a wad of paper towels or toilet tissue to the string line and let the vacuum suck the wad of paper through the line. It works pretty slick and saves all the hassle of threading string through each section of pipe as it's laid. Use long sweep conduit if you need to turn a corner and you should be in good shape.
I'm all set now. Except that you haven't offered to come over to do it all. <G> Time for a road trip?
We'll see what the coop says.
Thanks.PAHS Designer/Builder- Bury it!
Someone told me the dirt was softer here in California, it's not true! I've hand dug trenches in Louisiana and California and in both places it sucks. I don't believe that a shovel full of California dirt weighs any less, or more, than dirt in any other state. I've done a lot of trench digging in South East Asia, VN, and it did seem lighter there but that may have been because I was younger and in a lot better shape at the time. I rented a trenching machine for some water lines on a gentle sloping hillside, after about 20 feet the trencher got stuck and I ended up doing it by hand again. Another lesson that I continue to learn, pace yourself it's not a race!
> Someone told me the dirt was softer here in California, it's not true!
You can say that again. It can be like bad concrete. I use the Bosch hammer on it.
-- J.S.
There's a tool specifically made for finding faults like this.
http://www.toolup.com/ProductInfo.asp?Page=2&ID=PE2003&Manufacturer=Greenlee
Only $929. ;)
BTW, I have the same problem with the feeder running out to my barn. :( Only 325', one of the hots is high resistance. I tried to save money 17 years ago by using direct burial wire, and skipping the conduit. I guess now I know why the local POCO doesn't do direct-burial for underground services anymore.
I was thinking of trying to do the same type of thing with a fence charger, and a homebrew receiver.
Greenlee has great credibility here.
Finally heard from my U. electrician, who'd never heard of TDR. All they have is cable locaters which would depend on my using my welder to blow out the fault first.
Ain't gonna happen. Coop will add a new meter on the other end for $8.11/ft when I provide the trench. Monthly minimum is $19, including everything. Given the short distance, I'm meeting the coop engineer next Tues. and should have it wrapped up within 2 wks.
Only problem, which is surmountable, is my choice of generator location for outages. With 2 meters, I'd normally get either water or house current. With our house (never hot or cold), water is primary. I'm thinking other options.
Barry, much depends on how much current you need, whether you need 240 v., and how difficult a new trench would be.
PAHS Designer/Builder- Bury it!
I did not know "direct burial" cable was made in aluminum. Perhaps an improper cable type- like romex- was used?
This thread highlites why I say "put it in big pipe, and bury it deep-" even if the code allows an easier method.
"Deep" = less likely to get hit by the gardner, and suffers less from ground shifts.
"Pipe"= PVC in this case, so you can replace or add wires without digging up the yard again.
"Big" = one or two sizes over the minimum allowed. Much easier to pull, and there's room for future growth.
In the interim.... you could get some of those "handholes" (fiberglass, about 12" OD x 18" long), space them more or less equally along the run, and interrupt the wires there. That would allow you to narrow down the area of the break, and you could then replace only the bad section.
I do not like to directly bury splices- the handhole gives you access to check them later.
Otherwise, I'd pay particular attention to anywhere along the run where there is a change... a driveway, a big tree, a water line, etc. Quite often, thet's where the trouble is.
Aluminum direct burial is still common here, confirmed by my elec. distributor.
Doesn't look like a very wise choice from my seat.
Definitely not romex. You didn't notice the distance or wire size? This was a straight shot, through the forest.PAHS Designer/Builder- Bury it!
You're half rught; I saw the length, but not the size.
If you took a sample to your distributor, or you can read the markings, that I'm willing to accept that it is in fact UF. The #2 size doesn't throw me- romex is available in some large sizes, as well as SE cable, and even SO (extension cord type stuff). Heck, for #2, I'm surprised it's not USE, rather than UF. But I wander....
I have removed a number of like installs with improper wiring practices. I have to say that using the correct cable seems to be the exception, rather than the rule.
You may not have a "clean" break. If, for some reason, the insulation has rotted away from a section, you may have the voltage "leaking" out. A clue to this might be a section of dead grass or shrubbery.
I don't know if your measurements was made under load or not, nor do I know the size of the load. If the measurement was taken without any load at all, then that is one sick cable.
Since you're probably going to have to replace the entire run, you might also consider running a fourth wire, just in case you want a neutral (or second hot) later. Of course, if you run it in large pipe (as suggested earlier), you can pull in another wire later.