Lady Engineer
Senior Member
- Location
- New Jersey
Hi everyone,
I have a problem that I haven't encountered before. I've been doing MV substations for a little bit now, but one thing I've never seen is an undersized tie breaker.
I'm doing a Waste Water Treatment Plan upgrade. I may need to add another unit substation. There is one MV outdoor substation that feeds 4 unit substations, which are all located indoors. Every tie bus breaker (480V) in these substations is sized for half of the bus rating. I've always used fully rated tie breakers, but can't seem to find a reason to provide a tie half the size. The bus is rated for 2500A at 480V, the secondary breakers are rated at 2500A, but the tie bus breaker is rated 1200A.
What do you think? :?
I have a problem that I haven't encountered before. I've been doing MV substations for a little bit now, but one thing I've never seen is an undersized tie breaker.
I'm doing a Waste Water Treatment Plan upgrade. I may need to add another unit substation. There is one MV outdoor substation that feeds 4 unit substations, which are all located indoors. Every tie bus breaker (480V) in these substations is sized for half of the bus rating. I've always used fully rated tie breakers, but can't seem to find a reason to provide a tie half the size. The bus is rated for 2500A at 480V, the secondary breakers are rated at 2500A, but the tie bus breaker is rated 1200A.
What do you think? :?