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#208085 12/24/12 01:29 PM
Joined: Dec 2012
Posts: 3
0volt Offline OP
New Member
A separate structure (commercial trailer) with wheels removed being used as an office and storage is being supplied with 120/208 volts and is feeding a panelboard inside the trailer. The temporary feeder is a non-metallic cable assembly not known if hard usage and the supply power is being supplied from a panelboard inside a permanent building. The temporary cable feeding this structure has been in place for 3-5 years. The cable feed originates from a permanent building and is lying on mechanical room floor and passes through a metal louver vent outside to the separate structure. Outside the cable is run lying on the asphalt. The cable is exposed to employees/pedestrians and a portion of the cable is exposed to vehicle traffic and physical damage. The cable run is on the floor/pavement with no supports or protection.

I am being told this is a compliant temporary installation after looking at article NEC 590 and 1910.304 & 1910.305. The feeder is lying on the ground because 1910.305(a)(2)(v)(C) States: No branch-circuit conductor may be laid on the floor.

Why does OSHA say it is not permissible to have a branch circuit on the floor, but does not mention this about feeders?

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0volt #208086 12/24/12 04:04 PM
Joined: Jul 2004
Posts: 9,917
Likes: 29
I see problems in several areas there.

As for material, NM is not OK outside.

590.4(A)(B) Feeders. Overcurrent protection shall be provided in accordance with 240.4, 240.5, 240.100, and 240.101. Feeders shall originate in an approved distribution center. Conductors shall be permitted within cable assemblies or within multiconductor cords or cables of a type identified in Table 400.4 for hard usage or extra-hard usage. For the purpose of this section, Type NM and Type NMC cables shall be permitted to be used in any dwelling, building, or structure without any height limitation or limitation by building construction type and without concealment within walls, floors, or ceilings.

This is not "in" a building.

You also need to adequately protect cords and cables from physical damage.

(H) Protection from Accidental Damage. Flexible cords and cables shall be protected from accidental damage.

Running unprotected across the parking lot ain't it.
What I have seen that works fairly well is to make a trough from 2x6s on each side of the cable and staked down to the asphalt with 1x3s every several feet to lock everything together and hold the cord in place.

I would also question the time constraints.

Greg Fretwell
Joined: Dec 2012
Posts: 3
0volt Offline OP
New Member
The feeder cable type is not verified. It does not appear to be NM cable, but it could possibly be hard or extra-hard usage type cable. I have also been told the hard or extra-hard cables are designed for physical abuse, but trying to find any supporting documentation what type of abuse is acceptable that will not cause physical damage is not readily available.

The NEC & OSHA is very vague on this issue. It would be helpful with more examples of acceptable uses for cords and cables used for branch circuits and feeders for temporary wiring.

0volt #208089 12/24/12 07:00 PM
Joined: Jun 2004
Posts: 1,273
I'd put my money down on UF being the non-metallic cable assembly.

Is it grey?

Kind of flat?


Temporary hook-ups are limited to 90-days, by NEC.

Under no circumstances would a multi-year run -- under any guise be considered Code worthy.

Everythings okay -- until it isn't and the lawsuits start flying.

If the distance is not too great, an overhead triplex run, supported by a messenger wire, would be installed. ( Don't forget a bonding/grounding conductor, too.)

The cheesy hook-up back at the source has to go.

Get a real electrician out there.

With that set-up, you should have a rodent invasion with the next bad weather.

Tesla #208091 12/24/12 08:11 PM
Joined: Dec 2012
Posts: 3
0volt Offline OP
New Member
Originally this temporary trailer was to be used while remodeling was being performed in a section of a building and the remodel has been completed. The facility property is hundreds of acres and has many buildings on the property.

Due to having other construction and future construction even on other buildings on the property they are using 590.3(A) During the Period of Construction to justify the length of time.

The cable cannot be easily identified because of the length of time it has been used in this manner. Not only is the cable acceptable to physical damage, what about the weather elements including being rated for sunlight.

This is being approved by the safety manager, engineering and the other electricians because they are stating engineering and safety are the (AHJ). Their emphasis is on OSHA for safety and 1910.305(a)(2)(v)(C) States: No branch-circuit conductor may be laid on the floor and nothing is mentioned preventing having a feeder on the ground.

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