djd

[djd]

:huh:Most of you wont be surprised at this , but recently I was attempting to knockout a half inch hole in a 480v disco, I was having trouble , and knew my lead man was going to grill me for not doing it, " the knockouts wernt coming out without opening the 3/4", by the way I was landing an mc with a snap in connector. When he gave me the riot act I told him this was 480 and you couldnt use a snap in connector with 480, I dont even like to do it with 120v, he seemed to buy it, I had drilled the 1/2" hole for a secure fit. was I right in my code reference? Later I looked it up and its not a code violation very surprised to see it as an exception., was this ever Illegal?

 

[Dennis Alwon]

Hereis what 250.97 has to say

250.97 Bonding for Over 250 Volts. For circuits of over 250 volts to ground, the electrical continuity of metal race- ways and cables with metal sheaths that contain any con- ductor other than service conductors shall be ensured by one or more of the methods specified for services in 250.92(B), except for (B)(1).
Exception: Where oversized, concentric, or eccentric knock- outs are not encountered, or where a box or enclosure with concentric or eccentric knockouts is listed to provide a reliable bonding connection, the following methods shall be permitted:
(1) Threadless couplings and connectors for cables with metal sheaths
(2) Two locknuts, on rigid metal conduit or intermediate metal conduit, one inside and one outside of boxes and cabinets
(3) Fittings with shoulders that seat firmly against the box or cabinet, such as electrical metallic tubing connec- tors, flexible metal conduit connectors, and cable con- nectors, with one locknut on the inside of boxes and cabinets
(4) Listed fittings

 

[djd]

djd

I think I missed the are not encountered, unless listed it helps to put the beer down!