Underground Splicing

[knoppdude]

I recently removed a conduit supported junction can at a rock quarry, and replaced it with a bottomless handhole box. I spliced the wire with compression splices, and used heat shrink to insulate the splices. This is a washdown area, and the voltage is 480/277. The conductors are connected to a 200 amp breaker, and feed an office trailer. my worry is that the splices will deteriorate, and someday, someone will get shocked during a wash down of the area. Does anyone know if there are breakers that come with ground fault relay tripping capability? Thank you.

 

[Volta]

What type of panelboard?

Sqd D AK, AD, AL, AP, AM, and some other frames do.

 

[iwire]

No one makes a 480 volt GFCI and GFCIs are the only people protectors.

You could get a 480 volt 200 amp breaker with GFP but that does nothing to protect people from shocks.

 

[Volta]

No one makes a 480 volt GFCI and GFCIs are the only people protectors.

You could get a 480 volt 200 amp breaker with GFP but that does nothing to protect people from shocks.

Nothing? Not 4-6 ma, sure, but aren't we still in a 30 ma range for GFP?

 

[iwire]

Nothing? Not 4-6 ma, sure, but aren't we still in a 30 ma range for GFP?

You can get GFP at 30 ma but it will not protect people. (at least not directly) I do not know if any GFP settings for a 200 amp breaker will not drop down to a 30 ma anyway.

 

[Volta]

You can get GFP at 30 ma but it will not protect people. (at least not directly) I do not know if any GFP settings for a 200 amp breaker will not drop down to a 30 ma anyway.

I think this J-frame will go to 30ma, but you are probably right about this in general. Certainly passing 30ma though a person can be deadly, but if that leakage is detected ahead of that time is seems helpful. Maybe not as important as good drainage and sealing in the handhole, though.

 

[iwire]

Think of the difference in energy delivered to human body at 30 ma 277 volt vs 8 ma 120 volt.

I agree with what you said, make good splices with good drainage and things will be fine.

 

[chris kennedy]

I recently removed a conduit supported junction can at a rock quarry, and replaced it with a bottomless handhole box. I spliced the wire with compression splices, and used heat shrink to insulate the splices.

Sounds like a violation of 314.30(C). Can you use Polaris Blue?

 

[knoppdude]

This situation may indeed be a violation of 314.30(C), if it proves not to drain properly. The exact type of splices were compression butt splices, T&B, with slide on heat shrink insulation. There are actually several bottomless handhole boxes with splices in this feeder circuit. I think the best solution will be to replace the entire run with unbroken conductors. Until I can convince the area electrician to do this, the one thing I will do is perform an insulation test, which I will do ASAP. Thanks for all of the replies.

 

[don_resqcapt19]

Sounds like a violation of 314.30(C). Can you use Polaris Blue?

Chris,
Are you saying that heat shrink is not listed for use in wet locations?

 

[weressl]

I recently removed a conduit supported junction can at a rock quarry, and replaced it with a bottomless handhole box. I spliced the wire with compression splices, and used heat shrink to insulate the splices. This is a washdown area, and the voltage is 480/277. The conductors are connected to a 200 amp breaker, and feed an office trailer. my worry is that the splices will deteriorate, and someday, someone will get shocked during a wash down of the area. Does anyone know if there are breakers that come with ground fault relay tripping capability? Thank you.

Rock Quarry? That would be MSHA?!

Re: your concern, why would the conductor insulation themselves not deteriorate? Is the splice have a greater potential of deteriorating than the wires in the conduit themselves? Can you close up the box? It sounds like the tail wagging the dog.... I am not saying your concern is not valid, I just don't get how the source of the problem occurred, and not existed before, with the replacement of the box.

 

[chris kennedy]

Chris,
Are you saying that heat shrink is not listed for use in wet locations?

You tell me, I have never used it or researched it for an underground application.

 

[Volta]

You tell me, I have never used it or researched it for an underground application.

Nor have I, but UF splice kits have a special heat-shrink that contains a matierial that encapsultes the splice as the heated tube shrinks and is suitable for uderground conditions, so it can exist.

Also potting compounds intended for wet-niche fixtture in pools is probably quite appropriate in this situation, but never have looked into it.

 

[shepelec]

I stock direct burial splice kits on the truck for just such an application.
The particular style I have are good to 250mcm ( might be some bigger), they contain a set screw "butt splice" as well as an inner and outer shrink tube.

Gotta have the right parts and tools. :grin:

 

[don_resqcapt19]

You tell me, I have never used it or researched it for an underground application.

Many heat shrink kits are suitable for use underground and in wet locations. The heavy duty type will have a thickness that far exceeds that of the conductor insulation.

 

[kwired]

on farms around here repairing underground conductor failures is common.

Most repairs, outside of physical damage by excavation equipment or driving of steel fencepost into conductors, involve direct bury conductors and rodent damage. I have uncovered several failed splicing methods but never seen a failed compression connector insulated and sealed by an underground rated shrink tube. I trust the shrink tube more than the insulation on the conductor to take some abuse and still hold up.

 

[knoppdude]

Rock Quarry? That would be MSHA?!

Re: your concern, why would the conductor insulation themselves not deteriorate? Is the splice have a greater potential of deteriorating than the wires in the conduit themselves? Can you close up the box? It sounds like the tail wagging the dog.... I am not saying your concern is not valid, I just don't get how the source of the problem occurred, and not existed before, with the replacement of the box.

Weressl,
Yes, the box is covered. As for the problem of the wiring deteriorating, that condition may already exist. I did not have a means of testing the insulation before reenergization. There was no voltage drop from the feeder breaker to the trailer disconnect. If the Meggohm test is good, then I will probably use the underground splicing method that was mentioned in this thread. My interest in this, is that the wiring is safe, and now that I have touched it, I own it, so to speak. As for MSHA, they have the final say, but as this is a surface operation, and the equipment does not meet 90.2(B)(2), using the 2005 NEC, then I would think I have to abide by the NEC. I do understand what you are saying about the existing wiring, and it really is a mess, and I agree that the insulation may already be in jeopardy. The test will tell. Thanks.

 

[weressl]

Weressl,
Yes, the box is covered. As for the problem of the wiring deteriorating, that condition may already exist. I did not have a means of testing the insulation before reenergization. There was no voltage drop from the feeder breaker to the trailer disconnect. If the Meggohm test is good, then I will probably use the underground splicing method that was mentioned in this thread. My interest in this, is that the wiring is safe, and now that I have touched it, I own it, so to speak. As for MSHA, they have the final say, but as this is a surface operation, and the equipment does not meet 90.2(B)(2), using the 2005 NEC, then I would think I have to abide by the NEC. I do understand what you are saying about the existing wiring, and it really is a mess, and I agree that the insulation may already be in jeopardy. The test will tell. Thanks.

I don't believe that MSHA is restricted to underground operations. However if a mining facility also have a chemical processing plant that would use the material from the mining operation, the chemical plant itself would be an NEC plant NEXT to and under the same operation supervision as the MSHA mining plant.

 

[weressl]

Nor have I, but UF splice kits have a special heat-shrink that contains a matierial that encapsultes the splice as the heated tube shrinks and is suitable for uderground conditions, so it can exist.

Also potting compounds intended for wet-niche fixtture in pools is probably quite appropriate in this situation, but never have looked into it.

I am making a general observation: I think there may be a confusion exist in this post as some people uses the term 'underground' to mean subsurface or below grade, as in a basement and some are thinking in terms of direct burial, or even continuously submerged(in water).

 

[iwire]

I am making a general observation: I think there may be a confusion exist in this post as some people uses the term 'underground' to mean subsurface or below grade, as in a basement and some are thinking in terms of direct burial, or even continuously submerged(in water).

The splice kits Volta mentions are listed for direct burial.