MCB for IT lab trips after power cut

[anonymouse572]

One of our IT labs consistently trips following a power outage or isolation of the upstream supply by an electrician and won't reset until we've switched most of the sockets that computers are plugged into off. Once reset we can then switch the sockets back on again.

 

The breaker is a Hagar ADN 132 model 30mA RCBO B32.

Would I be correct to talk to our estates team about getting this changed for a RCBO with type C breaking characteristics to allow for what I guess to be electrical inrush to the capacitors in the power supplies of the PCs in the IT lab which currently prevents us from resetting the existing breaker.

 

We could just let it be as it is and continue to go to reset it following trips, but I am the only member of the IT team who can reach it without a ladder and it is half way across our campus on the first floor in a stairwell.

 

 

Let me know what is best to do here

[PotNoodleTech]

30ma is not much leakage total if the whole IT suite is on it (0.5ma of earth leak per device).

 

Really the only way to fix this is to have an electrician split the circuit into two so you'll have the original RCBO32 powering one half and a second RCBO32 powering the other half of the room.

[Andrew_C]

Inrush is actual current rather than leakage. This can be very high for an IT suite as all the capacitors in the power supplies charge up on the first cycle. This can cause tripping.

 

Again - the right answer is to split the load over more than one circuit.

[Andrew_C]

OR... And this is one we did here 20+ years ago; fit a couple of "delay on" relays to the final circuits. We found that the trips were happening up stream of the local breaker board.

[jmak]

You'll might also find that it gets worse and worse. The more they trip the more sensitive they become.