208 to 480 transformer

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big vic

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Having an issue finding a step up transformer 208 3ph to 480 3ph. Can I get a 480 to 208 and hook it up backwards?
 
big vic said:
Having an issue finding a step up transformer 208 3ph to 480 3ph. Can I get a 480 to 208 and hook it up backwards?
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Yes, but beware the 480 volt side is typically delta connected and has no "neutral". You will not have 277 volts capability, and if that is not a problem you still will either need to install it as a corner grounded system or as an ungrounded system which will need ground fault indication equipment. Either situation will mean you can't use 277/480 volt rated circuit breakers they will need to be rated 480 volts or 600 volts (without the "slash" in the rating).

Also if under 2014 NEC there was new section requiring a transformer used in this manner to be designed for such use, so you can no longer do so with just any transformer. It is a new section 450.11(B) and reads:"A transformer shall be permitted to be supplied at the marked secondary voltage, provided that the installation is in accordance with the manufacturer?s instructions."
 
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