portable building frame bonding

[dcl34769]

I am installing a bonding wire from the ground buss of a portable building(mobile home style but not a home) to the frame. The inspector is also requiring that I also drive a ground at the building and bond to it. My problem with this is that it this rod is in addition to the service rods thus creating multiple paths to ground. The site has two portable buildings with future expansion to five, service is a 400main that is mounted to a free standing rack. I belive that the grnd rod set at the portable building is wrong. Any help or opinions?????????

 

[charlie tuna]

Re: portable building frame bonding

it's not required but every parking lot pole here has a rod is driven next to it. there usless! but thats what the inspectors want. in your case, you might win this battle ---but you'll lose the war! your talking about twenty bucks in material and an hour's labor to make him happy. make him happy- you might need his help on a $5000. mistake on your part that he may have a solution!

 

[pierre]

Re: portable building frame bonding

dcl
Could you explain what the 'portable' building is being used for? Did you review Article 550? Check 550.4(A)

Pierre

 

[gregoryelectricinc]

Re: portable building frame bonding

I have also had inspector's require this to be done. My situation was a group of jobsite office trailers supplied by a common free-standing service. I ran a 120/240 volt 4 wire single-phase feeder to each trailer and set a disconnect 5' away from each one on a wooden post. I drove a rod at each post location and connected to the equipment grd terminal of disconnect switches. I then continued into the traier w/ 4-W feeder from disc. Inspector still required a rod bonded to metal traier frame. This made sense to me only after the inspector used the terminology "one building or structure supplied through another". In other words: treat each tralier like you would a detached garage.

 

[iwire]

Re: portable building frame bonding

We always put rods on Job trailers and the like and was under the impression it was required by 250.32.

250.54 allows you to add an ground rod and tie it into the EGC at any point.

250.32 Two or More Buildings or Structures Supplied from a Common Service.

(A) Grounding Electrode. Where two or more buildings or structures are supplied from a common ac service by a feeder(s) or branch circuit(s), the grounding electrode(s) required in Part III of this article at each building or structure shall be connected in the manner specified in 250.32(B) or (C). Where there are no existing grounding electrodes, the grounding electrode(s) required in Part III of this article shall be installed.

250.54 Supplementary Grounding Electrodes.
Supplementary grounding electrodes shall be permitted to be connected to the equipment grounding conductors specified in 250.118 and shall not be required to comply with the electrode bonding requirements of 250.50 or 250.53(C) or the resistance requirements of 250.56, but the earth shall not be used as the sole equipment grounding conductor.

[ August 15, 2003, 05:48 PM: Message edited by: iwire ]

 

[dcl34769]

Re: portable building frame bonding

Pierre, the "portable bldg" is being used as office space for the county school district.All the money FL makes of the suckers errr.... Tourists and thats the best they can do.