Recommended downstream protection

[BillP]

Dear All

Based on electrical characteristics of UPS Galaxy 5000 - 60 KVA, load current is about 87A but in installation manual section 2.4 recommended downstream protection is 20A and 32A circuit breaker.(see two attached image)

Can we use a circuit breaker in about 80A?

please guide us.

Best regards,

Tohidi

[BillP]

Hello,

I asked our EMEA support on this. Here is what I received:

I don't see any issue with an 80A circuit Breaker so long as they use 35mm² Cable. That would comply with European norms.
The 20A and 32A circuit breaker seems to refer to the largest MCB on the sub-circuits.

[BillP]

Dear Angela

Thank you for your reply.

60 KVA UPS can provide 87A in output.

Why we can not use circuit breaker more than 20A and 32A.

Best regards,

Tohidi

[BillP]

Hi,

Here is some further information I can share:

When we talk about circuit breaker more than 20A and 32A., we are talking about the sub-circuits. We make this recommendation to avoid having the UPS going into bypass just because of a fault on one circuit. The main output breaker can be higher as long as there is sufficient discrimination.

You will find further information in this link:

http://www2.schneider-electric.com/documents/technical-publications/en/shared/electrical-engineering...

[BillP · Accepted solution]

Dear Angela,

Thank you for your reply. It was useful.

Now I have another question. Our UPS is Galaxy 5000 - 60 KVA and we have only one load with 70A.

Can we use one output breaker with 80A (for example NS80H MA  80A schneider compact circuit breaker)?

Best regards,

Tohidi