bushing used to replace locknut

[lynch_family2]

I recently checked a job out for a friend of mine and found that the electrican that did the job didn't use locknuts on the inside of the enclosures. He had used grounding bushings. I had thought it was a code requirement to use locknuts and than the bushing. 300.4 of the 2002 code states "Conduit bushings constructed wholly of insulating material shall not be used to secure a fitting or raceway." Of course the bushings were made of metal, but I had really thought you had to use a locknut first than the bushing. If anybody knows that if it is a requirement to use a locknut first, please let me know the article number. Thanks

 

[russ]

Re: bushing used to replace locknut

Locknut's, double, required

Hazardous (classified) locations, 501.16(a)
Mobile homes, 550.10(f)
Over 250 volts to ground, 250.97
Recreational vehicles, 551.47(b)

Excuse the code numbers, they are off my Chicago disk. They should coincide with the 99 NEC.
I believe after a little looking, as long as the bushings are listed for grounding purposes, the installation is within code.
It's not what I'm use to seeing or installing either.

Russ

 

[russ]

Re: bushing used to replace locknut

This is only part of the article.

300.4(f)
Conduit bushings constructed wholly of insulating material shall not be used to secure a fitting or raceway. The insulating fitting or insulating material shall have a temperature rating not less than the insulation temperature rating of the installed conductors.

I listed this article because it seems to imply, that if the bushing is not fiber or plastic, it's ok to use in place of the inner locknut.

Also of interest 250.94

[ September 01, 2003, 06:31 PM: Message edited by: russ ]

 

[lynch_family2]

Re: bushing used to replace locknut

Originally posted by russ:
[qb] Locknut's, double, required

russ, thanks for the help. i guess i can skip that second locknut from now on. i don't think i will but now i know.

thanks jim

[ September 02, 2003, 09:35 AM: Message edited by: lynch_family2 ]