Car Wash

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websparky

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Cleveland, Ohio
I am reviewing plans for a car wash this week and think the metal ceiling panels may need to be bonded to the electrical service. The building has masonry walls with wood roof trusses. The metal ceiling panels are attached to the bottom of the wood trusses. Each of the 3 wash bays are separated by a masonry wall and are open at each end so you can drive in and out. The equipment room has a metal ceiling also and an attic access panel. The EMT conduits run through the attic and down the masonry walls to supply the self serve controls and the wall mounted wall pack lights. The EMT is not in contact with the ceilings except in the equipment room where they pass-thru to the attic. The lights in the equipment room are attached to the metal ceiling.

So, the question is; Do the metal ceilings need to be bonded. If so, code reference please.
 
Re: Car Wash

250.104(c), says, Structural Steel. Exposed structural steel that is interconnected to form a steel building frame and is not intentionally grounded and is likely to become
energized shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient
size, or the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with Table 250.66 and installed in accordance with
250.64(A), (B), and (E). The points of attachment of the bonding jumper(s) shall be accessible.

now the real question is whether or not these(panels) are considered part of the building frame...........? probably not.
 
Re: Car Wash

Originally posted by websparky:
Humm.. nobody has an opinion or can find a code reference for this? Everyone must agree that the panels need to be bonded!
Thanks!
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websparky, were not you the first, if not among the many who told me that it is a permisive code.

if noone can find an article saying you have to bond the ceiling, then you dont.
 
Re: Car Wash

I feel it is not unreasonable to request the metal ceiling the equipment room to be bonded due to the fact that it is subject to personal contact and may become energized. As far as the other bay ceilings, I guess this would be a judgment call on your part.
 
Re: Car Wash

How about this?

Approach the EC in a kind way and explain your concerns and possible solutions.

Ask if they do not agree it is a possible hazard that could be easily fixed.

I do not see a code section that requires it.

What do you see energizing it?

The raceways passing through it are required to be bonded.
 
Re: Car Wash

Bryan,
I feel it is not unreasonable to request the metal ceiling the equipment room to be bonded due to the fact that it is subject to personal contact and may become energized.
Click to expand...
How is the ceiling subject to personal contact?
Don
 
Re: Car Wash

Often, equipment that may become energized may also be considered grounded by the EGC of the circuit likely to do the energizing. If this metal ceiling is in contact with conduit, it seems to me that it may be considered grounded by this very same conduit.
 
Re: Car Wash

Bond it. scwirenut already showed the relevant section. The FPN to 250.105(c) interprets it to require that 'exposed metal building framework that is not intentionally or inherently grounded to be bonded to the service equipment or grounding electrode system.' Which makes sense. Ever have a static shock? If it's visible, you're seeing at least 2000 volts. That roof is sitting out in the wind, building up a charge, just like a huge capacitor. Imagine if there's lightning! I, for one, wouldn't want to explain to some roofer's wife how 'I didn't get it' after he sets his aluminum ladder against it.
ps day 1 of pacbell training they tell newbies how one employee walked up to a mobilehome with a downed power pole sitting on the roof in back.

[ January 21, 2006, 08:33 PM: Message edited by: peteo ]
 
Re: Car Wash

Originally posted by peteo:
Bond it. scwirenut already showed the relevant section.
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250.104(c) does not apply to the steel that forms the ceiling.

Read the section and you notice it says

Exposed structural steel that is interconnected to form a steel building frame

Websparky stated;

The building has masonry walls with wood roof trusses. The metal ceiling panels are attached to the bottom of the wood trusses.
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There is no way to stretch 250.104(C) all the way to metal ceiling panels.

This building does not have a structural steel building frame. :)
 
Re: Car Wash

Bob,
Both you and scwirenut brought this point up. I get it now, and stand corrected in my interpretation. Thanks.
 
Re: Car Wash

Maybe 250.4(A)(4)and(5) would cover this if in the opinion of the AHJ there was "likely to become energized", especially the ceiling in the equipment room where there is an attic access in the metal ceiling.
 
Re: Car Wash

Dave if you want to go down the "Likely to be energized" road do you have reason to believe that this ceiling is likely to become energized.

Just what will energize it?

All the electrical equipment that is in contact with the ceiling is already required to be bonded.

Let me ask this.

At your local big box home improvement store would you require all the steel racks to be bonded?

Do you believe any AHJ would require these racks to be bonded?

IMO both answers are no, the racks, if served with electricity will be bonded by the wiring method suppling the power....just as the steel ceiling in your car wash.
 
Re: Car Wash

Bob,
I agree with you. I too believe the metal ceiling panels are not likely to become energized. In the wash bays, there isn't any electrical anything close to the metal and in the equipment room all of the metal conduits are grounded.

Thanks to everyone for their help.
 
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