ECN Forum Forums Code Related Discussion NEC & other Code issues Legality of Shore Power Cable

Don, yes, I saw it in 310.13, but didn't see any articles like 320-340, which I'd expect to see if RHW were allowed to be used in the way I've seen shore power cable used, EG, laid on the ground temporarily connecting large commercial power loads. As I do not intend to run this in strict accordance with article 300 methods, I was hoping to find a clause allowing some relaxation of techniques. Specifically, that this cable should be installed in raceways. I know extension cords are not required to be run in raceways, but I couldn't find anything in articles 400 or 590 permitting it for type W, letalone 300 permitting it for RHW...


400.4 might give an easy out, as it allows for other cables used, if a special investigation deeps it acceptable. As mil-spec marine shore power cables are clearly legal to lay on the ground, span long distances without support and carry high levels of current, the investigation would be short and positive, I'd expect.

Steve,
The RHW rating alone would not permit that use for applications covered by the NEC.
Don

Using cables not listed in the table are "subject to special investigation" according to 400.4. This is one of those times that engineers, and others, get to make their case for varying from standard practices.

I don't mean to say that this is a 'blank permit' to use any old wire that might be about; rather, there is absolutely no way for the code to list every possible type of cable (especially ones not yet invented).
There are numerous specialty cables that may turn up, whose use may (or may not) be appropriate. Buss Drop cable, Stage and lighting cable, Boat cable, Shipboard cable .... the list goes on. I, for one, have no idea how "boat" cable differs from "shipboard" cable, but they are two different listings.
A more common situation where unusual cables might appear is with the assembly of imported production equipment. It is very possible that machine sections might be interconnected using cables that are not identified according to NEC classifications.

All this supposes the correct use of terms by everyone. The term 'welding cable' seems to be applied indiscriminately to any fat, supple cable.

I consult the UL "White Book" for additional information as to what a type designation may mean. For example, I am told that if welding cable has ratings different than 60 degree and 100 volts, it will be marked on the cable. Since there is no mention of testing for outdoor, wet, or sunlight exposure, I cannot assume that the cable is rated for those uses.

As for the connectors and lugs used, this was discussed in IAEI News. ("Do You Know Where Your Cables Are Tonight" , Jan/Feb 2005). It appears that there are actually industry standards for stranding; "normal" stranding is called 'Class B.' Much of the specialty cables have class K or M stranding.
UL standards require that terminals, lugs, and connectors be marked if they are suitable for use with other than "normal" wire. While the article also discusses longer-barrel crimp connectors, I have also seen terminations where multiple set screws pressed against a plate that, in turn, gripped the wire. The article refers to instances where a set screw, in direct contact with the wire, may break off strands as it is tightened.

So, in answer to the original question (Are these cables suitable?) I have to look more closely at the cable, and it's connections. I'd then have to research exactly what the cable has been listed for.

Granted my ship board experience was on warships built to defeat the axis powers but the shipboard cable I remember was covered in a galvanized steel braid about as heavy as a Kellems grip but very tightly woven.
I have never seen that on a "boat".

Thanks John I understand more what you where trying to convey.

That said why would I want to choose a cable that I would have to jump through hoops to use when portable power cable is readily available that is listed in Table 400.4?

I used to have a job that required hooking up power to traveling bands and if they had cable that was simply welding cable I would not hook up. They would usually end up renting the right cable or if I had enough on hand I would loan it to them.