Feeder Breaker Sizng for Dry type transformer
Feeder Breaker Sizng for Dry type transformer
(OP)
I am sizing a feeder breaker for a 112.5KVA Transformer(600v/208v). As per Canadian Electrical Code.The primary breaker shall be sized not larger than 1.25FLA (Pri)if the secondary breaker is sized larger than 1.25FLA(sec).Therefore I chose 150A FDB cutlerhammer Circuit breaker.But it is also noticed that this breaker may trip on inrush current(12FLA). In this case. can we choose a larger size of CB, like 200A. or alternatively, we can choose a different type of CB with adjustable digit trip unit.
Any inputs would be appreciated.
Any inputs would be appreciated.






RE: Feeder Breaker Sizng for Dry type transformer
Rafiq Bulsara
http://www.srengineersct.com
RE: Feeder Breaker Sizng for Dry type transformer
Rafiq Bulsara
http://www.srengineersct.com
RE: Feeder Breaker Sizng for Dry type transformer
12FLA = 1300 Amp
150 Amp breaker @ 10X instantaneous setting = 1500 Amp.
Another option may be to down size the secondary breaker to 1.25FLA(sec)
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Feeder Breaker Sizng for Dry type transformer
FDB 150 Amp breaker has a fixed characteristic. The instantaneous settings range between 800A and 1600A.
RE: Feeder Breaker Sizng for Dry type transformer
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Feeder Breaker Sizng for Dry type transformer
Alan
----
"It's always fun to do the impossible." - Walt Disney
RE: Feeder Breaker Sizng for Dry type transformer
RE: Feeder Breaker Sizng for Dry type transformer
Rafiq Bulsara
http://www.srengineersct.com
RE: Feeder Breaker Sizng for Dry type transformer
Bill
--------------------
"Why not the best?"
Jimmy Carter