MCB tripping on UPS power up - Greece

[roeften]

Hello,

I have a UPS 2000VA (1080W). The ups is at 20% load. Its powered up through a 10A MCB. There are no other appliances connected to the MCB.

When the power fails the ups holds for some time. If it fails and then the power is restored, the MCB trips.

The cable length from the MCB to the UPS is 5m.

Any thoughts why this may be happening?

Thank you.

 

[Moss5]

http://en.wikipedia.org/wiki/Inrush_current
http://en.wikipedia.org/wiki/Circuit_breaker

 

[roeften]

Thanks for your reply,

I was thinking of trying a Type C (now I am using a type B - sorry for not mentioning that) because the problem is inrush current as you suggested.

I did notice that the MCB is tripping only if there are appliances (like a switch) which are powering up themselves together with the UPS. Otherwise it does not.

Cheers

 

[plugwash]

using a type C is likely to fix the issue but you should be aware of the ramifications of this with respect to fault disconnection (you need a lower fault loop impedance to gaurantee fast trip on shorts) and local regs before installing it.