replace a 3p motor in a old builidng which no grounding
replace a 3p motor in a old builidng which no grounding
(OP)
Hi, I was asked to replace a new 3phase 208 Voltage,10hp motor to a old one. But unfortunatly, the old feeder to control panel no grouding,so how can I grunding?, befor the old motor no grunding still worked long time,Can I igord the grunding in this situation? Thank so much for reply.





RE: replace a 3p motor in a old builidng which no grounding
RE: replace a 3p motor in a old builidng which no grounding
Thanks so much for reply. Yes, the feeder is metallic conduit,but I want to know whether the inspector will approal or not as per the code if we assume the feeder conduit will serve as a grounding. Since We installed a lot new feeder with EMT,it is metallic, but we still need a grounding wire inside the EMT.
RE: replace a 3p motor in a old builidng which no grounding
If the motor is near a mass of metal that is grounded I would consider bonding the motor frame to that also.
Roy
RE: replace a 3p motor in a old builidng which no grounding
Per section 250.118 of the NEC, both rigid and EMT conduit can be used as an acceptable means of and EGC as dpc mentioned above.
I would think that with these being listed as acceptable means in the NEC, that inspector would have no problem approving them.
RE: replace a 3p motor in a old builidng which no grounding
EMT may be used, Rule 10-804, (d) subject to some exceptions.
Watch your connection to the motor. Flex is not acceptable for grounding. You may not transition directly to flex unless there is a grounding conductor oin the EMT
You may, however, use a junction box or condulet to transition from EMT to flex and run a grounding conductor in the flex from the motor to the box or condulet.
Rule 10-618 (3)
If this building is over 50 years old, and the EMT is coupled and connected by "indent" fittings, they may not be acceptable for grounding.
Bill
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"Why not the best?"
Jimmy Carter
RE: replace a 3p motor in a old builidng which no grounding
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If it is broken, fix it. If it isn't broken, I'll soon fix that.
RE: replace a 3p motor in a old builidng which no grounding
RE: replace a 3p motor in a old builidng which no grounding
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: replace a 3p motor in a old builidng which no grounding
RE: replace a 3p motor in a old builidng which no grounding
RE: replace a 3p motor in a old builidng which no grounding
In this old building,I just did exactly as Waross advised; wired a ground inside the flex from motor to the box/control panel.