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iochoa
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Join Date: Dec 2008
Posts: 7

UPS and Neutral Connection

10/07/2010 4:48 PM

I have a circuit where I need to install a UPS. It will be feed by a system with Tansfer automatic switch, it is mean the neutral will be break during transfer . I know that the best solution to avoid the break of the neutral is to install a isolation transformer for the UPS but what is the problem if just I connect the neutral to earth after the main circuit breaker that feed the UPS.
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msamad
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Location: Houston, USA
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#1

Re: UPS and Neutral Connection

10/07/2010 9:00 PM

Maybe I didn't understand your question correctly or you didn't make it clear. What I understood is your UPS is fed by dual source. If one source fails, the ATS switches it to the other source. In this case, why do you think the neutral breaks during the transfer? The UPS output supply (including its neutral) is completely isolated from the feed supply. The neutral of the UPS output is generally grounded within the UPS (as you meant by 'what is the problem if just I connect the neutral to earth after the main circuit breaker that feed the UPS') and there is no reason that the neutral of UPS output breaks during the transfer of the source.

I would suggest you to do a quick test and see if the UPS output remains ok during the transfer.

- MS

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PWSlack
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#2

Re: UPS and Neutral Connection

10/08/2010 9:31 AM

Neutral to earth? Eh? Why?

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