I have a customer that wants to install a single phase 120/208v coffee brewer to a 3 phase panel. Can this be done safely? The unit uses 220v for heating elements and 120v for control board.

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    You'd have to know a lot more stuff about the particular 3-phase panel you're trying to attach to. There are many kinds, and any mismatch will result in boom. – Harper Mar 14 at 0:48
  • Can you post photos of the nameplate on the coffee maker? Also, do you know what voltage your customer's panel uses? – ThreePhaseEel Mar 14 at 1:52
  • @ThreePhaseEel I am waiting to read YOUR solution sweetheart! Please, when you dismiss other comments please tell WHY. To simply say all of my words are wrong is not really helpful, don't you think? – stormy Mar 14 at 6:54
  • Sounds like something is off here " install a single phase 120/208v coffee brewer" does not make sense to me with " unit uses 220v for heating elements" – batsplatsterson Mar 14 at 11:18
  • @stormy -- you are making several presumptions about the OP's situation before all the facts are in – ThreePhaseEel Mar 14 at 11:43

Single phase power is just one (or two) poles of a 3 phase system, ALWAYS. So no, there is no "safety" issue, it is done all the time. The only issue is that it MIGHT be that the heating elements inside of the coffee brewer are configured to be connected Line-to-Line, instead of Line-to-Neutral. If so, then they will get 208V instead of 240V. Since the elements have a fixed resistance, the wattage output of the elements will drop to 75% of what they are rated for at 240V (P = V squared / R). That then will mean that it will just take longer for it to heat up the water.

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    Some systems do not have a neutral, or it is not carried to the point of use. This is unlikely to be the case with a 120/208V supply (as the 120 is the voltage to neutral), but possible with large supplies feeding only motors. Plus, single phase can be derived directly from the source (inverters, smaller generators etc). – Someone Somewhere Mar 16 at 0:03

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