Bonding Bushing for A/C Disconnect

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George Stolz said:
If not in this scenario, then what scenario would the special listing (over 250V) kick in?
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What I am saying is that the listed devices that are mentioned are nothing like a reducing washer so I am not sure that is the intent. Why not just say listed devices and leave it at that. I will try and call NFPA today and see what they have to say...
 
DARUSA said:
What about if you have a ground fault in your conduit?
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With a EGC properly installed, as long as one end of my conduit is grounded properly, you have a safe, low impedance return path for the fault. If I'm using the conduit only as my EGC, then you need to make sure both ends of the conduit are grounded properly.

I know all 4sq boxes are listed so the concentrics can carry fault currents abouve 250V. Not sure about the Sq D disco you have, but if memory serves me correct, they too, are listed. However, it's easy to install the ground bushing rather than get into it with the inspector. Some battles just ain't worth picking, IMHO. And for the extra $2, I'll add the bushing to the list of materials.

Now 10 years ago, I would have picked this battle and argued until I won. I guess age is mellowing me a bit. :)
 
FWIW, I just talked to NFPA and Chris told me that George is correct. He assumes there must be some reducing washers out there that are not listed. If the reducers you use are listed than no bonding bushing is required.

Damn, I hate being wrong, again....:)
 
ONE word, or two or three:
I HATE concentric knockouts on discos, panels and such. 1900 boxes, sure, but panels. Just leave the middle space where you have the concentric KO empty.
When you try to connect them, they never match, so now I have an 1-1/2" hole over half their concentric crap. I'm not talking about the 1/2"-3/4" ones. I'm talking about the ones 1-1/4 through 2".
BIGGEST pain in the behind.

George Stolz said:
If I have an A/C disconnect for a 480v air conditioner, do I need a bonding bushing on the EMT serving it when entering through a concentric knockout?
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Strife said:
ONE word, or two or three:
I HATE concentric knockouts on discos, panels and such. 1900 boxes, sure, but panels. Just leave the middle space where you have the concentric KO empty.
When you try to connect them, they never match, so now I have an 1-1/2" hole over half their concentric crap. I'm not talking about the 1/2"-3/4" ones. I'm talking about the ones 1-1/4 through 2".
BIGGEST pain in the behind.
Click to expand...

Psst. Don't tell anyone, but you can get cans/tubs (panel enclosures) without knockouts.
 
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