bonding bushing / concentric KO

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TOOL_5150

TOOL_5150

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Location
bay area, ca
I failed an inspection, inspector said I need a bonding bushing on conduit @ subpanel.

Situation: 40A, 240v feeder to detatched structure, ran 3/4 rigid underground came right up into small surface mounted subpanel. Drove a rod and a GEC to panel. I also ran a EGC IN the 3/4 conduit. The panel has concentric knockouts and I just put a regular bushing on it. Who is right?

~Matt
 
benaround said:
Matt, Did he cite 250.96 ?
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I dont know [I was just told "insp. wants bonding bushing"] I dont have any code books with me, but I want to get an answer to the office if insp is wrong or if I need to go change it.

I believe I am OK because there is a EGC in the pipe.


~Matt
 
Sure.......

250.96 Bonding Other Enclosures.
(A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non?current-carrying parts that are to serve as grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any nonconductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces or be connected by means of fittings designed so as to make such removal unnecessary.
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chris kennedy said:
Sure.......
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crud. Ok, and this failed ONLY because of concentric KO's then right? Thats what I get from it, because supposedly eccentric KO's are allright for a ground path.

ANd secondly, since reducing washers are listed for grounding, I could remove all concentrics, and put in chinese money and not need a bonding bushing, right?

~Matt
 
250.96 could be a good guess benaround.

".....with or without the use of supplementary equipment grounding conductors, shall be effectively bonded where necessary to ensure electrical continuity......."

Now I don't normally call it, but it could be what he's after.
 
cowboyjwc said:
Now I don't normally call it
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Because the language is vague.

250.96 Bonding Other Enclosures.
(A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non?current-carrying parts that are to serve as grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any nonconductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces or be connected by means of fittings designed so as to make such removal unnecessary.
Click to expand...

I could easily argue that I used RMC for physical protection and not as an EGC.
 
chris kennedy said:
Because the language is vague.
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That and the fact that sometimes it takes a sledge hammer and half a stick of dynamite to get those knockouts out. Kind of depends on the electrican too, if the knockouts are all tweeked then I may ask for it, if everything is neat and clean then probably not..

And using your argument, I might agree since you did pull a ground wire.

Sometimes as an inspector I have to admit that just because I might not call it, doesn't mean it's not a good call.
 
Heres a pic of the panel in question.

petaluma.jpg


Ben, I was more just asking to know - I hate using chinese money unless I have to.

~Matt
 
250.96 Bonding Other Enclosures.
(A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non–current-carrying parts that are to serve as grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any nonconductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces or be connected by means of fittings designed so as to make such removal unnecessary.
Click to expand...


This is where I dont see any argument...

Since concentric KO's arent listed to be used as an effictive ground, I dont have much ground to stand on - excuse the pun.

~Matt
 
chris kennedy said:
Read post 12 again.
Click to expand...

I understand but it is all one sentence. Let me shouw you how I read it.


250.96 Bonding Other Enclosures.
(A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non–current-carrying parts that are to serve as grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them.
Click to expand...

Simplified: Metal raceways shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them.

I do not intend the pipe to be the EGC, but it states: with or without the use of supplementary equipment grounding conductors

So Regardless - I see it saying anything that is metal, that doesnt have an approved method of bonding, needs to be mechanically bonded.

~Matt
 
Matt, More enclosures are listing their concentric ko's for grounding lately, I hope you

checked the labels inside that box? I'm sure you did.
 
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