Using Ground to Complete Circuit

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CBuchheit

New User
Location
Portland, OR
Occupation
Controls Engineering Manager
I'm building a UL 508A control panel and the customer wants to start the motor using the thermal switch in their motor as the overload device. That is of course allowed in section 34.1.3. The issue is they want to the contactor coil to go through this thermal switch and then use the *equipment ground wire* as the return path back to the control panel for this control circuit. They say they do it all the time and I don't doubt that it would work, but I can't imagine this is allowed by code. So what UL or NEC reference can I point to prove it isn't?
 

SceneryDriver

Senior Member
Location
NJ
Occupation
Electrical and Automation Designer
You can not use the equipment ground as a normal current path. The thermal switch must come back to the contactor circuit as separate conductors.


SceneryDriver
 
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