Help! Residential underground splice failed

[newservice]

"Scotchkote" is a good product to use on nicks. If it has been working for 2-1/2 months since the excavation they did not pull anything apart but still could have done some damage and even taped it up or something thinking they would be ok with that.

.

The fill was very rough, no 2 inches of sand in the bottom of that trench. Am thinking now put it in pipe. Also, in the splice box that Ill be putting in, what type of connectors there? Those connectors use a sleve and are rated forthe gauge wire Im using, the 4/0 goes directly in with no sleeve and the 2/0 you cut the sleve on the right ring and use that, inside is filled with antiox and the connector is rated copper or al. Thanks to all for the feedback very useful.

 

[ptonsparky]

Those splice kits are junk, but normally they last longer than a few months. I have replaced way to many of them. Crimp style butt splices and heat shrinks is the best way to go. A simple unnoticed nick no matter how minor can cause grief in a hurry. Scotchkote, tape, and scotchkote for bruises. Tape & Gel wraps for more serious insulation damage.

 

[ActionDave]

Am thinking now put it in pipe....

Good thinking. If not this time then for sure the next.

 

[kwired]

Those splice kits are junk, but normally they last longer than a few months. I have replaced way to many of them. Crimp style butt splices and heat shrinks is the best way to go. A simple unnoticed nick no matter how minor can cause grief in a hurry. Scotchkote, tape, and scotchkote for bruises. Tape & Gel wraps for more serious insulation damage.

You would think we see a lot of same type of things I couldn't have said it any different. Heat shrink is only way to seal aluminum underground conductors. Everything else seems to fail eventually.

The fill was very rough, no 2 inches of sand in the bottom of that trench. Am thinking now put it in pipe. Also, in the splice box that Ill be putting in, what type of connectors there? Thanks to all for the feedback very useful.

Rough fill could be the cause of the problem. Why put it in pipe if the first part (if I understand you just extended an existing service lateral) is not in pipe? Not like you can pull conductors out and replace them if not a complete raceway. Why do you need a splice box? If you don't use a method that seals well enough it will not matter that they are in a box they will still fail.

 

[Dennis Alwon]

AFAIK they seal just because of tight fit - therefore careful selection is necessary - too loose of fit and you don't have a good seal.

I hope that is not the case as one unit does from #2 to 750KCM-----This is why I didn't think they were water tight

 

[kwired]

I hope that is not the case as one unit does from #2 to 750KCM-----This is why I didn't think they were water tight

That particular one probably has stepped boot that you need to trim according to size of conductor used. I have a polaris splicer I somehow ended up with though I normally don't use anything but crimped butt splicers and shrink tube, I will have to look at it again but pretty sure you must use conductor that will fit tight for a good seal and the outer covering is a silicone like material. May or may not be gel inside.

 

[newservice]

You would think we see a lot of same type of things I couldn't have said it any different. Heat shrink is only way to seal aluminum underground conductors. Everything else seems to fail eventually.

Rough fill could be the cause of the problem. Why put it in pipe if the first part (if I understand you just extended an existing service lateral) is not in pipe? Not like you can pull conductors out and replace them if not a complete raceway. Why do you need a splice box? If you don't use a method that seals well enough it will not matter that they are in a box they will still fail.

Original job was in pipe. But yeah now that the thing is built shouldn't be any issue with movement and now not having pipe is probly fine. Splice box is what the GC is asking for. Again, probly not gonna do that or he can do it himself. Another case of letting someone else dictate how the work is done and the results thereof.

 

[hurk27]

While I have no idea as to why it failed, I question why your utility allows you to do splices in conductors ahead of their meter, this is very surprising as here any conductors ahead of their cash register is only done by them as if there is any fault or problem by state law they are responsible for any repairs, and any leakage of current they want to control.

I found some of the best heat shrink tubing "now get this" at one of the most unlikely places I would have ever looked, our local Menard's, it has a hot glue that totally envelops the conductors and like what Dennis has said I have never had one fail, but with three conductors in it impossible to seal all three with heat shrink unless it is made for it, and I have never seen a heat shrink with three openings that would work for this, the DB Polaris taps do work but if any pressure tries to bend the conductor at the point it enters the tap it can open the seal enough to allow moisture to enter the connection and cause its failure, depending upon the conductor size aluminum will burn off usually between one to two months if exposed to the earth by any moisture getting to it.

I do allot of trailer parks here and conductor failure is very common because of one reason or another, the reasons are endless, new trailers conductors are put in PVC now and we haven't had the failure with them like the ones not.

Our utility has a crimp on splice tap that work great, and this is what they use for taps mid way, it totally seals the connections and has a encapsulate gel in it that when they do the crimp some of it runs out the ends letting you know it is sealed, I have a line man who give me a few from time to time and I have never had one fail, but I have never found a source for them or know the cost.

 

[Fulthrotl]

Original job was in pipe. But yeah now that the thing is built shouldn't be any issue with movement and now not having pipe is probly fine. Splice box is what the GC is asking for. Again, probly not gonna do that or he can do it himself. Another case of letting someone else dictate how the work is done and the results thereof.

well, if you have a damaged cable, you are gonna need TWO splice boxes, and i
don't see the benefit of it... unless you are gonna run conduit between the boxes
and pull wire, then make it up to the direct buried stuff in the box.
i'm fond of cold shrink tube and hypress myself, but if the kit you used is listed for
direct burial, then it isn't your issue.

3M cold shrink is thick, has waterproof adhesive inside it, and can be submerged in
water.

when i do most anything, i megger the wires before heating them up, and after that,
it's not my dime.

"cable was in, and certified to 1000V. why yes, i'll be happy to repair the damage done,
there will of course, be an additional charge."

ideal has a pretty good cable tracer you can put a signal into an open cable and see
where it dies off at... it's about $1,200 new.

 

[newservice]

3M cold shrink is thick, has waterproof adhesive inside it, and can be submerged in
water.

when i do most anything, i megger the wires before heating them up, and after that,
it's not my dime.

"cable was in, and certified to 1000V. why yes, i'll be happy to repair the damage done,
there will of course, be an additional charge."

ideal has a pretty good cable tracer you can put a signal into an open cable and see
where it dies off at... it's about $1,200 new.

Great info, thanks..will let you know soon.

 

[Fulthrotl]

Great info, thanks..will let you know soon.

http://multimedia.3m.com/mws/mediaw...9bnY_sFWuRFWtsFWtsFWtsFssssss--&fn=8420DS.PDF

cold shrink 8426-9 will probably get you where you need to go. 2/0~250 range.

don't forget the most important part of repairing his damage after meggering it...

billing. very important. incorrect billing will lead to failure of the whole thing eventually.

 

[newservice]

http://multimedia.3m.com/mws/mediaw...9bnY_sFWuRFWtsFWtsFWtsFssssss--&fn=8420DS.PDF

cold shrink 8426-9 will probably get you where you need to go. 2/0~250 range.

don't forget the most important part of repairing his damage after meggering it...

billing. very important. incorrect billing will lead to failure of the whole thing eventually.

HA! So psyched!! My brother has a $5k OTDR that will pinpoint the fault and show all the resistances graphicly, for a fee hes stopping by in the AM after the poco disconnects. GC has backhoe ready.

 

[newservice]

http://multimedia.3m.com/mws/mediaw...9bnY_sFWuRFWtsFWtsFWtsFssssss--&fn=8420DS.PDF

cold shrink 8426-9 will probably get you where you need to go. 2/0~250 range.

don't forget the most important part of repairing his damage after meggering it...

billing. very important. incorrect billing will lead to failure of the whole thing eventually.

HA! So psyched!! My brother has a $5k time domain refractometer scope that will pinpoint the fault and show all the resistances graphicly. For a fee he's stopping by in the AM after the poco disconnects. GC has backhoe ready.

 

[ptonsparky]

HA! So psyched!! My brother has a $5k time domain refractometer scope that will pinpoint the fault and show all the resistances graphicly. For a fee he's stopping by in the AM after the poco disconnects. GC has backhoe ready.

Let me know if he gets closer than .5 inch.

 

[kwired]

While I have no idea as to why it failed, I question why your utility allows you to do splices in conductors ahead of their meter, this is very surprising as here any conductors ahead of their cash register is only done by them as if there is any fault or problem by state law they are responsible for any repairs, and any leakage of current they want to control.

I found some of the best heat shrink tubing "now get this" at one of the most unlikely places I would have ever looked, our local Menard's, it has a hot glue that totally envelops the conductors and like what Dennis has said I have never had one fail, but with three conductors in it impossible to seal all three with heat shrink unless it is made for it, and I have never seen a heat shrink with three openings that would work for this, the DB Polaris taps do work but if any pressure tries to bend the conductor at the point it enters the tap it can open the seal enough to allow moisture to enter the connection and cause its failure, depending upon the conductor size aluminum will burn off usually between one to two months if exposed to the earth by any moisture getting to it.

I do allot of trailer parks here and conductor failure is very common because of one reason or another, the reasons are endless, new trailers conductors are put in PVC now and we haven't had the failure with them like the ones not.

Our utility has a crimp on splice tap that work great, and this is what they use for taps mid way, it totally seals the connections and has a encapsulate gel in it that when they do the crimp some of it runs out the ends letting you know it is sealed, I have a line man who give me a few from time to time and I have never had one fail, but I have never found a source for them or know the cost.

I don't think OP mentioned whether it was ahead of meter or not, he did indicate that the splices were for extending conductors because of the construction of an addition, so it wasn't exactly a maintenance thing that prompted the splicing but rather a change of service location. I'm not sure what you are thinking when you say when talking about sealing all three conductors. If you are talking about making taps - I don't think that is what is being done, if you are talking shrinking something on all three service conductors.... I don't think that is what you are talking about - never seen anything for that kind of use. Small UF cable repair kits but they only good for up to 10 AWG copper and up to 4 conductors in a cable assembly.

 

[hurk27]

I don't think OP mentioned whether it was ahead of meter or not, he did indicate that the splices were for extending conductors because of the construction of an addition, so it wasn't exactly a maintenance thing that prompted the splicing but rather a change of service location. I'm not sure what you are thinking when you say when talking about sealing all three conductors. If you are talking about making taps - I don't think that is what is being done, if you are talking shrinking something on all three service conductors.... I don't think that is what you are talking about - never seen anything for that kind of use. Small UF cable repair kits but they only good for up to 10 AWG copper and up to 4 conductors in a cable assembly.

I don't know why? maybe because post 1 stated "and rout the other directly into the meter" and post 5 stated "And they didn't specifically say Approved for Service conductors"

So I give

 

[Hv&Lv]

HA! So psyched!! My brother has a $5k time domain refractometer scope that will pinpoint the fault and show all the resistances graphicly. For a fee he's stopping by in the AM after the poco disconnects. GC has backhoe ready.

I would be very interested to see how close a TDR is on triplex URD. An A frame earth return fault locator is usually best for secondary. The varying impedances in triplex wire seem like it would make it hard to pinpoint with any real accuracy. You would need to much information for it to get very close. Insulation type, wire impedance, and then here is the splices that will throw the measurement off. What velocity factor (VOP) will you use?

I like a TDR, but in conjunction with a thumper. They work great with shielded or concentric cables. We will check cable or neutral condition, or just to see how many splices are in a particular stretch of line with one. The TDR will put me within 10-20 feet of a fault, then I set the thumper off to pinpoint. We still have to input the velocity of propagation for the measurement to be anywhere near close. I hope it works for you. keep us posted

 

[hurk27]

I guess I read it kind of fast last night but I will also add the in post 10 he said "We didn't want to go to the street cause would have to tear up driveway." which also led me to believe they are service conductors, as far as a 3-way tap, I think I got that from him saying he used a Polaris multi tap with the rubber plugs, which I wouldn't expect on just a straight through splice when there are much lower cost straight through set screw slice kits available?

 

[Dennis Alwon]

I guess I read it kind of fast last night but I will also add the in post 10 he said "We didn't want to go to the street cause would have to tear up driveway." which also led me to believe they are service conductors, as far as a 3-way tap, I think I got that from him saying he used a Polaris multi tap with the rubber plugs, which I wouldn't expect on just a straight through splice when there are much lower cost straight through set screw slice kits available?

Post 5

And they didnt specificly say Approved for Service conductors, only approved for Direct burial, but whats the diff? 4/0 cables and 2/0 neutral.

 

[hurk27]

I would be very interested to see how close a TDR is on triplex URD. An A frame earth return fault locater is usually best for secondary. The varying impedances in triplex wire seem like it would make it hard to pinpoint with any real accuracy. You would need to much information for it to get very close. Insulation type, wire impedance, and then here is the splices that will throw the measurement off. What velocity factor (VOP) will you use?

I like a TDR, but in conjunction with a thumper. They work great with shielded or concentric cables. We will check cable or neutral condition, or just to see how many splices are in a particular stretch of line with one. The TDR will put me within 10-20 feet of a fault, then I set the thumper off to pinpoint. We still have to input the velocity of propagation for the measurement to be anywhere near close. I hope it works for you. keep us posted

I have a Dyana that in using just the RF in tracing mode hooking up to the lost conductor will drop the signal off about 6" when I pass the bad section and if I mark it where I loose the signal, then turn around and trace it back from the other direction again it will drop off about 6" past the break, mark and directly between these two marks is the break, but why when I have the fault locater attachment for the Dyna? it hits it dead on.

It's a Dynatell 2273 with the falt locator bow. I found mine on E-bay for $2500.00 like new, but I have seen them go as high as $3k new they were over $5k to $6k