Construction Trailer grounding electrode

[RJH333]

Is a 100amp 4 wire feeder cable (2 conductors, 1 grounded conductor, and 1 grounding conductor) feeding a construction trailer on a job site from a 400 amp 120/208 temp service with 2 ground rods allowed to exempt me from using ground rods at the trailer for a grounding electrode ?

 

[pete m.]

550.4(A) requires that it shall meet all other applicable requirements of 550. Then you would want to reference 550.33(A)(2).

I see no exemption.

Pete

 

[ceb58]

Is a 100amp 4 wire feeder cable (2 conductors, 1 grounded conductor, and 1 grounding conductor) feeding a construction trailer on a job site from a 400 amp 120/208 temp service with 2 ground rods allowed to exempt me from using ground rods at the trailer for a grounding electrode ?

What code cycle are you under. 2008 you must have the rod.

 

[iwire]

What code cycle are you under. 2008 you must have the rod.

and 2005 and 2002 and 1999 and ......

 

[RJH333]

OK I put them in!

 

[M4gery]

Wow, ya learn something new everyday!

 

[eprice]

550.4(A) requires that it shall meet all other applicable requirements of 550. Then you would want to reference 550.33(A)(2).

I see no exemption.

Pete

I doubt 550 applies to this. Construction trailers that I see don't meet the definition of a mobile home. However, they would be a separate structure and 250.32 leads to the same answer.

 

[hurk27]

I doubt 550 applies to this. Construction trailers that I see don't meet the definition of a mobile home. However, they would be a separate structure and 250.32 leads to the same answer.

You are correct, a construction trailer is a article 545 building, and this is what it says:

545.12 Grounding Electrode Conductor.
Provisions shall be made to route a grounding electrode conductor from the service, feeder, or branch-circuit supply to the point of attachment to the grounding electrode.

doesn't really say an electrode is required to be installed at the trailer, just an 250.66 conductor back to the main service?

 

[iwire]

You are correct, a construction trailer is a article 545 building,

I agree and have said the same many times.

The only time that changes is when a mobile home is used as a construction trailer.

 

[eprice]

doesn't really say an electrode is required to be installed at the trailer, just an 250.66 conductor back to the main service?

I think 545.12 is just recognizing the fact that it may be difficult to run a grounding electrode conductor at the set up site since the walls are finished. It is therefore requiring that provision be made for the routing of that grounding electrode conductor. This section doesn't over ride requirements in 250 for grounding electrode systems.

 

[earlejohnson]

i would put a rod

 

[iwire]

Y

doesn't really say an electrode is required to be installed at the trailer, just an 250.66 conductor back to the main service?

I also do not see anything that says 250.32 does not apply.

 

[hurk27]

I also do not see anything that says 250.32 does not apply.

I wouldn't think so, but the wording is strange for the NEC, its the only article that states this, all other 500. articles require a 250.32 electrode

The only thing that makes sense to me, is maybe they were trying to require the GEC to be run out of the building like in mobile homes similar to this:

550.32(B)(3) Means shall be provided for the connection of a grounding electrode conductor to the service equipment and routing it outside the structure.

but why not the same wording?