MCCB Pole parallel

Assuming its a US based system and under NEC regulations in most applications yes you can double up or even triple up on circuit breakers to achieve current ratings greater than a single common sized breaker comes in.

Many Primary breakers are in fact 2 and occasionally three smaller units running in parallel with a common physical connection between them internally or through their levers.

The big question is is your electrical service designed to handle loads in excess of your present 650 amp limit?

Also what are you doing that needs over 650 amps on a single phase system?

Thanks.........

Its 120 KVA 1 Phase 220V AC output for UPS System.

My math says that 120 KVA on a 220 VAC system is only 545 amps.

To me that suggests that you grossly overloading your UPS system to be running out of capacity at 650 amps?

UPS can be loaded upto 110% for 10 mins; so current is around 600A accordingly on a safer side estimating 650A max. current.

I still don't see the point of putting a 800 amp capacity breaker system on circuit that only sees 600 out of its present 650 amp capacity being used.

Are you having regular issues with the 650 amp breaker tripping due to overloads?

If so your peak load demands are likely well past what the UPS system was designed for or intended to service which means that changing to a 800 amp circuit capacity on a UPS system designed to not see above 650 amps is likely just going to cause a massive system failure at some other point such as your input fuses or the primary switching devices themselves or with a connection on one or more of the high current handling points/parts in the system burning up.

I can use 630A MCCB also but i feel that 400 4P MCCB will be economically good & too without compromising the required protections. Also this will be on safer side for nuisance tripping; and in future we can set the O/C setting to values lower than 800A (400A) as it can be set from around 0.4 to 1 of rated current.

Question

1.400A 4poe mccb available can it be used for 650amp single phase by paraleling.

Yes you can. When you do that you will face problems like

1.Overload protection will not work ( if there is thermal overload setting it would have designed to operate the max for 400A + 10%. It will not withstand for 650A)

2.The MCCB is designed to use for a 4 wire application and not for 2 wire application and protections (magnetic,thermal,overload etc;) will not work properly.

Answer will be exchange the MCCB with a correct sized one as per your requirement.

Dear sir,

Basically a pole in a MCCB has been designed for the continuous running current, if you parallel it, the current passing through may be divided into equal halves in phase if in normal -0-220v system, but in case of 2wire system without neutral ie. 110-110v, then equal current will flow in all three poles - that means - 650A will be divided as 215,215,215 amps, then if it is a adjustable type MCCB, then you have to set the tripping point of OC and EF considering this 215Amps as ur full load.

Well, a 650A circuit will have a larger cable than a 400A one. So the answer could be, "no, because the cable won't fit the terminals".