1000va tramsformer

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mannyb

Senior Member
Location
Florida
Occupation
Electrician
we installed a 1000va tranforner 480v 120v single phase for an 120v outlet for a computer router. does the neutral side of 120v need to be grounded to frame of xfmr? If its required to be to have gec and MBJ to enclosure or frame could you provide the nec requirement if not can could you do the sameI only find 250.134 ex for class 1 2 or 3 circuits 1000va or less and that would be not required if bonded to frame
 

mannyb

Senior Member
Location
Florida
Occupation
Electrician
we installed a 1000va tranforner 480v 120v single phase for an 120v outlet for a computer router. does the neutral side of 120v need to be grounded to frame of xfmr? If its required to be to have gec and MBJ to enclosure or frame could you provide the nec requirement if not can could you do the sameI only find 250.134 ex for class 1 2 or 3 circuits 1000va or less and that would be not required if bonded to frame

Basically I trying to ask does the neutral side on the 1000va transformer for 120v need to be grounded?
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
The exception for small Transformers only applies to whether or not you have to connect it to a grounding electrode. For a small transformer you are only required to connect a neutral to the incoming equipment grounding conductor. Everything else would be the same
 

kwired

Electron manager
Location
NE Nebraska
250.20(B) seems to indicate it must be grounded. How to ground it is another issue.

BTW a two wire secondary has no neutral, and you can ground either conductor. Which ever one you do ground becomes the "grounded conductor".
 
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