inspector141
Senior Member
- Location
- Westminster, MD
Can an existing 120/240, 4 wire delta service be fed from a 120/240 3 phase Y connected generator via a transfer switch? I'm assuming the existing service is not slash rated breaker(s)
You cannot have a "120/240 Y" connected 3-phase generator, however you can have a 208Y/120 one.Can an existing 120/240, 4 wire delta service be fed from a 120/240 3 phase Y connected generator via a transfer switch? I'm assuming the existing service is not slash rated breaker(s)
Other than the fact that your 240V loads may not be happy with only being supplied with 208V?Yes, I thought the same thing. I'm going to look at it later this afternoon.
Assuming the generator is 120/208, 4 wire Y, would that be legal and safe for that generator to serve a 4 wire delta 120/240 volt service temporarily when a power outage occurs?
Other than the fact that your 240V loads may not be happy with only being supplied with 208V?
I'm guessing yes, as in high leg.Also, this 4 wire delta system is not grounded at any point is it?
You cannot have a "120/240 Y" connected 3-phase generator, however you can have a 208Y/120 one.
Then it is a 240/120 delta 3-phase unit.Cummins model DGDK, 125kVA Standby rated (for example) is available in 120/240 3 phase voltage.
Then it is a 240/120 delta 3-phase unit.
A lot of equipment rated to operate at 240V will be fine with 208V but it should be verified with the equipment. A lot of equipment can tolerate +/- 20% voltage regulation however more sensitive eqiupment might be +/- 10%.
Also, this 4 wire delta system is not grounded at any point is it?
I would suggest using a transfer switch that transfers the neutral and does not bond them.