UPS

[buck]

I will try to word this properly-- can anyone point me in the direction as to the grounding requirements on a cord and plug connected UPS? The supply is 4W 3PH 120/208, each end at the UPS is cord and plug. I am wondering what the requirements would be in regards to the grounded(neutral) being disconnected because of the cord?
Thanks for any help

 

[ron]

Re: UPS

I'm not sure I understand what the grounded conductor being grounded or not has to do with the cord.
It is odd that there be a cord and plug on the input and output, for a unit that is three phase.
Maybe you can give a manufacturer and model number or nameplate info so it is clearer.

 

[buck]

Re: UPS

Thanks for the reply Ron. I will revisit the site today and get more info off the UPS.
My question regarding the neutral was the fact if each end is cord and plug connected then is the neutral in essence switched? Which would reflect grounding requirements.
Have a Happy Thanksgiving

 

[petersonra]

Re: UPS

Originally posted by buck:
Thanks for the reply Ron. I will revisit the site today and get more info off the UPS.
My question regarding the neutral was the fact if each end is cord and plug connected then is the neutral in essence switched? Which would reflect grounding requirements.
Have a Happy Thanksgiving

Most of the time the UPS systems I have seen incoming ground feeds through to the outgoing power plug ground pin and the outgoing neutral and ground are bonded together.

However, I have never seen a 3 phase unit with incoming power on a plug.

I have often wondered if this arrangment presents a potential hazard in that if someone unplugs the UPS, it will still work but there will be no connection to earth, although it would still have SC/GF protection through the neutral-gnd bond on the outgoing power side.