6000A circuit breaker at 480V LVPCB
6000A circuit breaker at 480V LVPCB
(OP)
Has anybody ever used one this size at 480V. I am wanting to use a 6000A circuit breaker as my cross tie between (2) 2500kVA transformers on each side and was told they don't make them that big.






RE: 6000A circuit breaker at 480V LVPCB
Rafiq Bulsara
http://www.srengineersct.com
RE: 6000A circuit breaker at 480V LVPCB
However, you may wan't to rethink your idea. That is a lot of fault current you are proposing.
RE: 6000A circuit breaker at 480V LVPCB
RE: 6000A circuit breaker at 480V LVPCB
RE: 6000A circuit breaker at 480V LVPCB
Maybe I am just thinking wrong, perhaps a sketch would help.
RE: 6000A circuit breaker at 480V LVPCB
RE: 6000A circuit breaker at 480V LVPCB
"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". – Nikola Tesla
RE: 6000A circuit breaker at 480V LVPCB
RE: 6000A circuit breaker at 480V LVPCB
RE: 6000A circuit breaker at 480V LVPCB
FWIW, at a previous employer we had a number of boards fed from 2.5MVA transformers with 4000A incomers at 415V. We struggled to get a board with adequate fault bracing to allow paralleled operation, and the arc energy was approaching 200 Cal/cm2 when on a single feed (slow protection to coordinate with some big stuff downstream). At that energy level the question is whether the clean-up guys will need a vacuum cleaner or just a dustpan & brush to collect you, not whether you'll be alive or not.
Have you any option to split into two boards with smaller transformers?
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If we learn from our mistakes I'm getting a great education!
RE: 6000A circuit breaker at 480V LVPCB
RE: 6000A circuit breaker at 480V LVPCB
RE: 6000A circuit breaker at 480V LVPCB
RE: 6000A circuit breaker at 480V LVPCB
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If it is broken, fix it. If it isn't broken, I'll soon fix that.
RE: 6000A circuit breaker at 480V LVPCB
Why not a ring bus with two of the breakers open and the rest closed, something like:
CODE
| | | |
<-[x]---[x]-------[x]---[o]-------[x]---[x]-------[x]---[o]------>
| | | | | | | |
| | | | | | | |
[ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ]
That version adds in a few extra, but purchasable, breakers. A 12 breaker ring would save a breaker or two. Have an interlock scheme that never allows more than two transformers on any bus segment at once and you're good to go. Except you're still at the wrong voltage level.
RE: 6000A circuit breaker at 480V LVPCB
RE: 6000A circuit breaker at 480V LVPCB
Are the utility circuits synchronized? Is the utility aware that you want to parallel their circuits on the secondaries? Most would not allow that.
Alan
"The engineer's first problem in any design situation is to discover what the problem really is." Unk.
RE: 6000A circuit breaker at 480V LVPCB
Also to deal with the arc flash problem - I was going to install a maintenance switch and make it so nobody unauthorized would be allowed in the room and tie the door contacts and motion sensor into that.
At the end of the day I just want to deliver a safe system to my client. They already had everything worked out for me before I got there, so just trying to chizzle it back one thing at a time.
David - I really like your setup and I pitched that on day 1, but they said they want all 4 transformers supplying load at the same time. But I am going to fight the good fight.
RE: 6000A circuit breaker at 480V LVPCB
The Cutler-Hammer breakers may not coordinate above 100kA, if that's a concern.
Alan
"The engineer's first problem in any design situation is to discover what the problem really is." Unk.
RE: 6000A circuit breaker at 480V LVPCB
"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". – Nikola Tesla
RE: 6000A circuit breaker at 480V LVPCB
I also like davidbeach's suggestion.
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If it is broken, fix it. If it isn't broken, I'll soon fix that.
RE: 6000A circuit breaker at 480V LVPCB
RE: 6000A circuit breaker at 480V LVPCB
------------------------------------------------------------------------
If it is broken, fix it. If it isn't broken, I'll soon fix that.