Cable or wire in pier side trough containing water pipe

[smfloyd]

There is a concrete trench on the deck of a water side pier that contains a 4 inch diameter water pipe. The trench is about 2 feet wide by 18 inches deep. It is desired to run 480 VAC 3 phase in this same trench. We want to run either G-GC CABLE or XHHW-2 wire. Question, do either of these need to be in their own conduit/raceway?
My concern is NEC 300.8

 

[ActionDave]

I don't know what G-GC cable is but if you run your own conduit for the wiring I don't see a problem.

 

[smfloyd]

Thanks ActionDave. The question is do they need to be in conduit or can they be just laid in the trench as if it were cable tray. Here is a link for the G-GC cable:

Medium Voltage SPEC 44140

industrial.southwire.com

 

[tom baker]

The cable spec states "Not for use as permanent building wiring". It seems like a very robust wiring method, for "flexible, portable, and extra-hard usage applications"
I would use PVC conduit with expansion couplings and XHHW-2 conductor

 

[smfloyd]

Thanks Tom, the electrician/contractor just wants to bundle the 480 VAC 3 phase XHHW-2 and lay it in the trench. I think conduit is required/good idea. I’m trying to find a NEC code requirement for the conduit.

 

[ActionDave]

300.3 says you have to use Chapter 3 wiring for XHHW. I don't know anything about G-GC cable.

 

[tthh]

Thanks Tom, the electrician/contractor just wants to bundle the 480 VAC 3 phase XHHW-2 and lay it in the trench. I think conduit is required/good idea. I’m trying to find a NEC code requirement for the conduit.

Can't make sense to lay XHHW-2 in a trench with a water pipe. What about the poor plumber who comes along in 5 years? Makes no sense.

 

[electrofelon]

Can't make sense to lay XHHW-2 in a trench with a water pipe. What about the poor plumber who comes along in 5 years? Makes no sense.

Maybe, but that is a design issue not a code issue. I don't care about "a trench".
if someone wants some separation, give me distance instead of this "not in same trench" nonsense.

 

[smfloyd]

Can't make sense to lay XHHW-2 in a trench with a water pipe. What about the poor plumber who comes along in 5 years? Makes no sense.

I agree, but I need more of a leg to stand on other than “the poor plumber”

 

[tom baker]

Thanks Tom, the electrician/contractor just wants to bundle the 480 VAC 3 phase XHHW-2 and lay it in the trench. I think conduit is required/good idea. I’m trying to find a NEC code requirement for the conduit.

No conduit needEd if the trench is a chapter 3 wiring method.
just ask your electrician for the concrete trench article number

 

[tortuga]

the electrician/contractor just wants to bundle the 480 VAC 3 phase XHHW-2 and lay it in the trench. I think conduit is required/good idea. I’m trying to find a NEC code requirement for the conduit.

As others have pointed out 300.3 and I'll add 300.2:

300.2 Limitations.
(A) Voltage. Wiring methods specified in Chapter 3 shall be
used for 1000 volts, nominal, or less where not specifically limited in some section of Chapter 3.

300.3 Conductors.
(A) Single Conductors. Single conductors specified in
Table 310.104(A) shall only be installed where part of a recognized wiring method of Chapter 3.

There is only one exception:
Exception: Individual conductors shall be permitted where
installed as separate overhead conductors in accordance
with 225.6.

 

[wwhitney]

Since the application under discussion is on a pier, isn't there something in Chapter 5 that bears on this question? Maybe that would allow the G cable laid in the trench?

Edit: looks like 555.13 would be applicable, and cable would only be a possibility if the trench is on the underside of the pier or "flexibility is necessary as on piers composed of floating sections"

Cheers, Wayne

 

[Fred B]

There is a concrete trench on the deck of a water side pier that contains a 4 inch diameter water pipe. The trench is about 2 feet wide by 18 inches deep. It is desired to run 480 VAC 3 phase in this same trench. We want to run either G-GC CABLE or XHHW-2 wire. Question, do either of these need to be in their own conduit/raceway?
My concern is NEC 300.8

Concrete trench on a deck of a pier? Or is this a jetty? How are you getting a "concrete trench" into a pier? What sort of covering would be on this "concrete trench"?
XHHW-2 is not listed to be installed "unprotected", it might contain additional listing for direct burial and thus protection by burial. But a concrete trench is not direct buried, but in this suggested application "concrete trench" is being used as a raceway. If this "trench" is going to contain "foreign" (non electrical) installation, it would seem you can't also count it as a raceway thus any electrical installation would require it's own raceway within the "trench". Anybody considering installing plumbing through your electrical enclosures or raceways?

 

[augie47]

IMO, Since it's a pier, Art 555 will allow the G Cable without conduit. Installations such as that have been approved locally (doesn;t mean they are correct but our AHJs approved)

 

[wwhitney]

IMO, Since it's a pier, Art 555 will allow the G Cable without conduit.

555.13(A)(2) allows certain "portable power cables" in two cases:

(1) As permanent wiring on the underside of piers (floating or fixed)
(2) Where flexibility is necessary as on piers composed of floating sections

I don't see how a trench in the deck of a pier meets (1)? I guess you could interpret "underside" to mean "anywhere below the walking surface".

Cheers, Wayne

 

[smfloyd]