3 Phase UPS - Unbalanced Loads

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Charz

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I have a UPS (3 Phase, 230V AC, neutral not grounded) There are 3 phase and 2 phase (Phase to Phase) loads connected to this UPS. Apparently, there would be unbalance current between the phases due to the two phase loads as it is not connected evenly across all the phases.

Do the breaker trips for the unbalance current?. I don't think the breaker trips as there is no neutral. Does it cause any other issue?
 
Charz said:
I have a UPS (3 Phase, 230V AC, neutral not grounded) There are 3 phase and 2 phase (Phase to Phase) loads connected to this UPS. Apparently, there would be unbalance current between the phases due to the two phase loads as it is not connected evenly across all the phases.

Do the breaker trips for the unbalance current?. I don't think the breaker trips as there is no neutral. Does it cause any other issue?
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Usually a three pole breaker will trip all three poles when the current through any pole exceeds the rating of the breaker. They don't care if the current is not the same through all the poles.
 
Neutral not grounded??? Does that mean the UPS output is completely floating with relation to the EGC? If so, that's very wrong for many reasons, starting with that there's no path for a fault-to-ground to trip the breaker. (Look at the rules for grounding an SDS and also at the UPS's install instructions.)

You have three-phase loads (3 wires) and single-phase loads (2-wires), two-phase is a very different beast.
 
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