Separate Structure made of steel

[M. D.]

Originally Posted by raider1

.........

According to 250.104(C) I must size the bonding conductor in accordance with 250.66 and install the conductor like a GEC.

Chris

Only if the exposed structural metal has not been intetionally grounded .. once you satisfy this,. the rest is moot.

Can anyone show me where this can not be accomplished by use of the grounding conductor of the circuit??

[M. D.]

Originally Posted by benaround

Dennis,

I really don't see any other section that pertains to your situation except for 250.32, Its'

I think it could be argued that section 250.104(c) applies to exposed structural metal as described whether or not there is even a branch circuit run to the building .

[benaround]

M.D.,

What do you think of 250.32(B)(1), IMO, it covers this aspect.

[M. D.]

Originally Posted by benaround

M.D.,

What do you think of 250.32(B)(1), IMO, it covers this aspect.

I'd say I agree 250.32 (b) covers his situation.

[Pierre C Belarge]

Dennis
The equipment ground conductor installed with the supply conductors (12/3) is sufficiently sized.
Why 250.66 keeps being discussed I am not sure.


250.104(A)(3) Multiple Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s).

The bonding jumper shall not be required to be larger than the largest ungrounded feeder or branch circuit conductor supplying the building.



This is the last sentence of the subsection.



If you are supplying wiring to the metal structure, the question is not will it become energized, the comment is I do not know if it will ever become energized. That is good enough to say it the bonding is necessary, as in our industry we try not to leave any safety aspect in question.


If at worst, use a short bonding jumper connected to the box and the steel structure as your required bonding jumper. Then you are done .

[M. D.]

Originally Posted by Pierre C Belarge

Dennis
The equipment ground conductor installed with the supply conductors (12/3) is sufficiently sized.
Why 250.66 keeps being discussed I am not sure.


250.104(A)(3) Multiple Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s).

The bonding jumper shall not be required to be larger than the largest ungrounded feeder or branch circuit conductor supplying the building.



This is the last sentence of the subsection.

Yah,.. only that section deals with bonding metal water piping systems.


250.104(c) requires his frame to be ,.. and 250.32 says the EGC can be

[electricmanscott]

Originally Posted by Pierre C Belarge

Dennis


If you are supplying wiring to the metal structure, the question is not will it become energized, the comment is I do not know if it will ever become energized. That is good enough to say it the bonding is necessary, as in our industry we try not to leave any safety aspect in question.

I don't really agree. The NEC says "likely to become energized" . To me saying I don't know if it will become energized is allot different than saying it is likely to become energized.

Under normal conditions the building is likely NOT to become energized.

If the wording was "likely to become energized under xyz conditions" or "in the event of whatever" it might have more weight as far as an absolute requirement for bonding. In my view anyway.

[M. D.]

Two definitions ,.. niether of which are found in the NEC so take them for what they are I guess,... a couple more opinions

The NEC style manual

Likely to Become Energized: Failure of insulation on

by Jeffrey Sargent, Noel Williams
Likely to Become Energized:
Failure of insulation on energized parts or conductors........
..........likely in this sense does not address the probability that an insulation failure will occur.

[electricmanscott]

Originally Posted by M. D.

Two definitions ,.. niether of which are found in the NEC so take them for what they are I guess,... a couple more opinions

Those are great.

I guess the NEC just ignores the actual definitons of words and substitutes what they want something to mean.

[Dennis Alwon]

Well I called the nc state inspector because I was curious as to his interpretation. He absolutely agrees that the #4 bond is unnecessary and that the EGC of the circuit is all that is needed because it is a separate structure. I guess the rules change if this was an attached structure.