Under Ground Conduit Repair?

[FunfDreisig]

What is the best way to seal/repair a gaping gash in an under ground 3/4" electrical conduit when the wire inside is (miraculously) undamaged?

FWIW I ask this question because one the fools in our neighborhood (who will remain un-named to protect the guilt) managed to nick (as in, nearly cut in half) the electrical conduit (twice) with the teeth of his back-hoe while knowingly and purposefully digging directly over the conduit, in an attempt to locate the depth of the conduit and place a drainage pipe over the top of it. Please don't let the obvious insanity of the miscreant stop you from offering advice. I errr.... he would be eternally grateful for a solution that makes it possible to sleep in the house tonight, instead of the un-finished 3 bay garage

Thanks in Advance - Funf Dreisig

 

[walrus]

What is the best way to seal/repair a gaping gash in an under ground 3/4" electrical conduit when the wire inside is (miraculously) undamaged?

Any pictures? . Pull wire back, cut out the damage, recouple. If you have no plans of ever pulling wires thru that pipe again, making a clamshell out of larger pvc might work, glue it on and bury it?

 

[nadogail]

I have seen a snap around, glue in place fixer at a trade show. Sorry, I did not get the name or manufacturer. The "patch kit" is out there, check with a wholesale distributor.

I would not waste my time with a Big Box retail store.

 

[walrus]

I have seen a snap around, glue in place fixer at a trade show. Sorry, I did not get the name or manufacturer. The "patch kit" is out there, check with a wholesale distributor.

I would not waste my time with a Big Box retail store.

I don't think they make one that small? I think MRB posted a link to one a while back, Carlon maybe?

 

[sberry]

Wrap with pc of water and ice shield.

 

[RHD 4 LIFE]

If you wrap the broken section with a piece of tubing with a ID of the OD of the damaged piece and tape it up, then make a mold around it and pick up some 2 part liquid acrylic or epoxy and pour it around it!

 

[BoydS]

OK, your neighbor has a 3/4" underground conduit that now has this gaping gash in it due to digging over it with a back hoe knowing the location of the conduit to start with. You may be surprised, but this happens quite often in the industrial world and some of those back hoe operators are not around now. One thing you did not mention is what is this conduit ... PVC or RGS.

Assumming it's PVC, you may be outta luck with finding a split conduit that size as typically the smallest is 1". There are manufactures that have PVC conduit repair kits and I would suggest giving them a call as their websites might not list all they manufacture. Conduit Repair System (CRS) is one mfg that may be able to help. Carlon, being a huge mfg of conduit, may be another resource to call.

If you cannot locate a split conduit repair kit, I see only 2 options which will work for both PVC and RGS.

1) As previously mentioned ... pull the wires out of the conduit and make the repair. If you do that be sure to tie a pull rope onto those wires so you can repull.

2) Cut through the conduit and wires. There are mfgs that make a splice kit for underground wires (3M being one of the best). The UG conduits will then need to be stubbed up aboveground and into a box. The wires can then be fed though. The UG conduit will probably need to be sized up a bit to accommodate the splice.

Good luck with the repair...

 

[FunfDreisig]

Thanks for all the timely replies. The fool maybe sleeping in the house tonight

The conduit fixer I saw on the internet didn't go down to 3/4". But the idea seems sound. Tomorrow AM, when it finally gets down below 100 degrees, I plan on slicing some larger conduit in half (length wise) and see it I can fit it around the gashed 3/4in conduit tight enough to glue / seal. If not I'll try the water and ice shield idea and then cover it with a larger piece of conduit for 'overhead' physical protection.

FWIW this is the only 15ft section out of nearly 100ft of septic line (and electrical conduit) that I had not already excavated when I moved/added sewer line clean outs where it passes under the carport of the 3 bay garage i'm building. This small section was under the existing drive way and I 'knew' that it had been sleeved with 4" sch40 at installation (not by me). What I didn't realize was that the conduit had been installed higher than the septic line in this section Instead of beside the septic line as it had been over the remaining line that I had previously excavated. So the first touch was not the sch 40 sleeve but the conduit

Thanks again - Funf Dreisig

 

[Torque1st]

You can make your own repair couplings from ordinary PVC pipe couplings. Just remove the raised band inside a standard coupling with a rat tail file, dremel tool, or sandpaper and a dowel. Make the coupling a slip fit over the existing conduit. Slip the repair coupling back along the cleaned pipe. Then replace the damaged section of conduit with a standard coupling and a section of conduit. Cement the repair coupling with a quick addition of "extra" cement. You have to be very fast but it can be done. Practice may be required but that means you will have to make more than one repair coupling.

 

[hidollartoys]

If the wire in the conduit is direct burial, no harm no foul. Tape up the conduit with foil tape , wrap with high quality duct tape(gorilla) and bury.

AND quit digging there!!!!!!!

 

[Ray-CA]

I've repaired pvc sprinkler pipe as small as 1/2" with a "split coupler" type of device. Try looking in the plumbing section for the small repair kits.

Ray

 

[Falcon67]

You may be surprised, but this happens quite often in the industrial world

A few years back they were working on the start for a new building on campus. We have a lot of trees, mostly oak and pecan, with lots of roots. A backhoe op snagged on a "root" and gave it a good yank - oops, it was one leg of a three phase feed for that part of campus. Op was OK but weird stuff starts to happen when one leg of a feed goes down. We were dark for a while after that.

 

[nate379]

If it's direct burial it better not be in conduit to begin with!

If the wire in the conduit is direct burial, no harm no foul. Tape up the conduit with foil tape , wrap with high quality duct tape(gorilla) and bury.

AND quit digging there!!!!!!!

As for the repair, I would tape it up, take a piece of 1" conduit and cut it in 1/2 and put it around the damaged part and wrap that in tape. Ok maybe it's not OSHA, EPA, PETA, ATF, QVC, NEC, MIG, UAL, whatever "approved" but it'll work just fine.

 

[mrb]

If it's direct burial it better not be in conduit to begin with!





As for the repair, I would tape it up, take a piece of 1" conduit and cut it in 1/2 and put it around the damaged part and wrap that in tape. Ok maybe it's not OSHA, EPA, PETA, ATF, QVC, NEC, MIG, UAL, whatever "approved" but it'll work just fine.

lots of things will 'work' but why not do it right?

 

[Falcon67]

lots of things will 'work' but why not do it right?

He could use the method similar to what the previous owners of our house used to mate 4" iron waste pipe to plastic waste pipe - wrap it with aluminum foil, brace the two mating pieces with bricks and pour a sack of concrete over the joint. Really - have pics. Did you know you can Y pipes like that too?

 

[nate379]

Ok if you want to do it right, pull the wire, cut the broken part put a coupler and section of conduit and run pipe again... but...

how long is the run... will the wire even pull out... I mean you can turn a 15 min fix to a 2 month project if you really want.

lots of things will 'work' but why not do it right?

 

[ddawg16]

I bet it's the same fool that drove a ground rod through my conduit almost cutting in half the neutral wire and shorting out to one of the hots......the good news is the circuit breaker did it's job and my kids who where holding the ground rod while I, I mean the fool was up on the ladder smacking it with the sledge hammer did not get shocked.....

I vote for pulling the wire and replacing the bad section with a new piece.

Even though you are sure the wires are not nicked....better to pull them out and make sure...nothing is more fun than tracing a ground fault that is 100' in an underground conduit.....

 

[Aceman]

If it's direct burial it better not be in conduit to begin with!

As for the repair, I would tape it up, take a piece of 1" conduit and cut it in 1/2 and put it around the damaged part and wrap that in tape. Ok maybe it's not OSHA, EPA, PETA, ATF, QVC, NEC, MIG, UAL, whatever "approved" but it'll work just fine.

Why can't I put direct burial wire in conduit? I do it all the time...

Doing it half @ss versus doing it correctly takes about the same amount of time, maybe a little longer. So why not do it right?

Ok if you want to do it right, pull the wire, cut the broken part put a coupler and section of conduit and run pipe again... but...

how long is the run... will the wire even pull out... I mean you can turn a 15 min fix to a 2 month project if you really want.

If it takes you 2 mos. to repair a broken 3/4 conduit maybe your time would be better spent calling an electrician who could probably do it in an hour or so?

I'd unhook the wires at the j-box nearest the break, hook on a string/fish tape, etc pull the wires back so the wire head is right at the break. Unhook the string from the head, cut out the damaged conduit, install an expansion coup slid all the way open, tie the string back on, extend the expansion coup out and glue it up. Pull the wire back in.

Or pull the wire all the way out with no string attached and fish tape it later. This is easier if the run is short, you can cut and repair the conduit a lot faster without worrying about cutting the wires or string.

 

[VHF]

Situation: buried 3/4" PVC conduit damaged, wires inside OK.

Solution: Cut out a short section including the damaged conduit, say 10", without damaging the cables inside. (Use a pipe cutter for clean cuts on the the two ends, then perhaps a hacksaw along the length being very careful not to damage the wires.)

Cut a slightly shorter length of replacement 3/4" conduit and glue a coupling on each end. Let it dry. Then hacksaw it down the middle. The result is a 2-piece custom repair coupling, which is hopefuly just the right length to fit the gap.

Fit it in place around the cable with the exposed parts of the couplings overlapping the two ends of the buried conduit. Glue everything up, including the edges exposed by cutting the repair piece in two. Clamp it together with at least 4 stainless steel hose clamps. Voila!

 

[FunfDreisig]

Thanks again for all the ideas.

FWIW the damaged conduit run is over 150' with a severe dogleg (i.e. 90 degree) at about half way, over to the picnic table and back, then on to the 2nd outlet in vicinity of the new 3 bay garage. The original purpose of this circuit was to provide minimal GFI protected service at the picnic table for lights, fans, etc. The 2nd outlet turned out to be handy during construction for a battery charger, a skill saw, etc. The damaged section is after the picnic table. This end of the circuit is 'nice to have' but is completely expendable when the final electrical service to the garage is installed.

So I'm only looking for safe, quick, temporary solutions. If the only safe solutions involve pulling wires, I'll just discount the damaged end of the circuit at the picnic table and get on with life

FWIW I know I would still need to seal the gashes to keep water out of the conduit.

Thanks -- Funf Dreisig

 

[nate379]

I'm not an electrician but I was told buy a few that NO to direct burial on conduit. It can overheat since it's designed to use the dirt at a heatsink. True or not, I don't know.


Could take 15 mins, could take 2 monts. The wire might not be able to pull out and would require digging it.

Why can't I put direct burial wire in conduit? I do it all the time...

Doing it half @ss versus doing it correctly takes about the same amount of time, maybe a little longer. So why not do it right?



If it takes you 2 mos. to repair a broken 3/4 conduit maybe your time would be better spent calling an electrician who could probably do it in an hour or so?

I'd unhook the wires at the j-box nearest the break, hook on a string/fish tape, etc pull the wires back so the wire head is right at the break. Unhook the string from the head, cut out the damaged conduit, install an expansion coup slid all the way open, tie the string back on, extend the expansion coup out and glue it up. Pull the wire back in.

Or pull the wire all the way out with no string attached and fish tape it later. This is easier if the run is short, you can cut and repair the conduit a lot faster without worrying about cutting the wires or string.

 

[walrus]

FWIW I know I would still need to seal the gashes to keep water out of the conduit.

Thanks -- Funf Dreisig

Their's water in every underground pipe I deal with, some full to the top of the conduit, thats why you use wire rated for wet locations. I'd worry more about dirt.
If you're going to pull the wires out, hook a string on them. Its easier than fishing afterwards

 

[rinny_tin_tin]

I'm not an electrician but I was told buy a few that NO to direct burial on conduit. It can overheat since it's designed to use the dirt at a heatsink. True or not, I don't know.


Could take 15 mins, could take 2 monts. The wire might not be able to pull out and would require digging it.

Not true....direct burial does not know what kind of soils it will be used in, and PVC or metal conduit and even the air in the conduit voids has better thermal transfer capabilities than lets say sandy soil or clay. So..a direct burial cable inside a conduit inside a conduit is fine and is better protected.

 

[nate379]

Don't know. Just what I was told by several electricians. Not a local thing either because I was told the same here in Alaska and I first heard of this when I was in Idaho.

 

[rinny_tin_tin]

Don't know. Just what I was told by several electricians. Not a local thing either because I was told the same here in Alaska and I first heard of this when I was in Idaho.

I have heard it to from time to time, and when I ask for basis, I get everything under the sun - from electro-maganetical radiation to intermediate vector bosons.
Nothing in Code prohibits it --and only fill ratios are applicable - from what I see -- but who knows - sometimes there is basis in wivestales

 

[dipper]

A few years back they were working on the start for a new building on campus. We have a lot of trees, mostly oak and pecan, with lots of roots. A backhoe op snagged on a "root" and gave it a good yank - oops, it was one leg of a three phase feed for that part of campus. Op was OK but weird stuff starts to happen when one leg of a feed goes down. We were dark for a while after that.

Same exact thing happened here a few years ago as we put up a new 80million dollar laser. Operator dug through electric lines and put our building on the fritz with one or two phases missing. He was okay, but I think they had to get a new transformer and it had to be shipped across the state on a big trailer. It takes days for our laser system and controls to recover from power outages like that.

 

[FunfDreisig]

Thanks to everyone who posted in this thread. I incorporated many of your ideas in my solution.

1 - Cut away the damaged 3/4" conduit with a Dremel cutoff wheel.
2 - Sliced a 1' section of 1 1/4" conduit in half lengthwise.
3 - Duct taped the gashes for good luck*.
4 - Clamped the lower half to the damaged conduit.
5 - Applied a thin roll of J-B Weld to the lower half
6 - Zip Tied the upper half to the lower half
7 - Stuffed the ends with Silicone caulk
8 - Applied more J-B weld on the seams
9 - Clamped the whole thing with 4- 2" SS hose clamps
10- Sealed the ends with even more J-B Weld.

Thanks again for the suggestions - Funf Dreisig

* Any project that does not involve duct tape is incomplete by definition

p.s. I didn't put the romex in the under ground conduit -- the septic installer did. And I trusted his "experience and knowledge". BTW the septic installation is/was the ONLY thing inspected by the county.

 

[mrb]

wow, i didnt know it had romex in it. You cant use romex undeground, even in pipe. I would have replaced it (and made the septic installer pay for it)

 

[walrus]

Is it romex? or UF? . If its romex, its truly illegal but I'll bet nothing happens to it and it works fine

 

[FunfDreisig]

wow, i didnt know it had romex in it. You cant use romex undeground, even in pipe. I would have replaced it (and made the septic installer pay for it)

And yet our county septic inspectors approved the entire installation, including the romex in the under ground conduit. I was there the day of the inspection. Everything (sewer pipe and conduit,etc.) was already in the trench and fully hooked up (the trench was still open). But I didn't know about romex vs underground conduit, etc. at that time. Makes you wonder what exactly the county inspected

As I've posted previously, I'll be disconnecting/abandoning this circuit as soon as I get the final under ground electrical service installed for the garage. I'll do the install this time, so that I know it is right

Funf Dreisig

 

[FunfDreisig]

Is it romex? or UF? . If its romex, its truly illegal but I'll bet nothing happens to it and it works fine

I'm almost certain it is romex. See my previous post for details.

Funf Dreisig

 

[southpier]

take a Budweiser can, punch the top & bottom out, wrap around said conduit, secure w/ hose clamps.


oh wait; that's for the "tailpipe repair" thread