frizbeedog
Senior Member
- Location
- Oregon
Are you familiar with pole buildings? (wood frame, metal skin/siding)
I install electric services to a lot of these.
Usually I end up installing ground rods at these pole buildings and install a #6 GEC and pass it through a lug that I have installed on the metal skin of the building, just to bond the metal skin. But today I got to thinking...... I said to myself, "self, why are you bonding this metal skin?"
Here is the author's comment from Understanding the National Electrical Code, Volume 1, pg.207, regarding 250.104 (C) Bonding Exposed Stuctural Metal. Mike Holt:
So I got to thinking about these skins. Usually they are in vertical sections, mabey 4-6 ft wide. They come pre-painted and they overlap. They are joinded together by wood screws or sheet metal screws and the ones I encounter have a type of gasket under the head of the screw. At this point I am not convinced that there is good continuity between the sections of skin. So it seems to me that by doing this, I only end up bonding the one section.
I have been bonding thse skins for as long as I can remember but....given all of the above, is it really a good practice?
Why, or why not?
I install electric services to a lot of these.
Usually I end up installing ground rods at these pole buildings and install a #6 GEC and pass it through a lug that I have installed on the metal skin of the building, just to bond the metal skin. But today I got to thinking...... I said to myself, "self, why are you bonding this metal skin?"
Here is the author's comment from Understanding the National Electrical Code, Volume 1, pg.207, regarding 250.104 (C) Bonding Exposed Stuctural Metal. Mike Holt:
Author's Comment: This rule doesn't require the bonding of sheet metal framing members (studs) or the metal skin of a wood frame building, but it would be a good practice.
So I got to thinking about these skins. Usually they are in vertical sections, mabey 4-6 ft wide. They come pre-painted and they overlap. They are joinded together by wood screws or sheet metal screws and the ones I encounter have a type of gasket under the head of the screw. At this point I am not convinced that there is good continuity between the sections of skin. So it seems to me that by doing this, I only end up bonding the one section.
I have been bonding thse skins for as long as I can remember but....given all of the above, is it really a good practice?
Why, or why not?