MCB Trouble

Postby Very Confused » Tue Jul 10, 2007 12:18 pm

New distribution board in the garage has been working fine for a couple of weeks. Yesterday I discovered that the MCB for the sockets and the one for the Lights had both tripped.

I've checked the appliances - ie a frezer and a tumble dryer and they work fine and have no impact on the MCB on the house if run on an extension lead.

I've checked that there are no loose connections at the sockets and I've checked that there is no leakage to earth, everything seems okay.

However, on plugging anything into the sockets in the garage, there is a light buzzing from the 32 amp MCB, the more power drawn the greater the buzzing. It gets hot, and it trips the switch.

With the 32 amp MCB off and the 6 amp lighing MCB on, there is a faint buzzing. The more lights switched on the greater the buzzing, the MCB gets hot and trips out.

The RCD sometimes trips, sometimes not. Neither affect the main board in the house - there is no problem with the board in the house.

Any ideas?
Very Confused
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Simply Build It

Postby sparx » Tue Jul 10, 2007 7:08 pm

Hi, check loose connections at board , particularly make sure in comming cables to RCD are in the 'stirrups' not behind. try to pull them out Power off at house!!!terms can be tight but missing the cables totally!
only other thing to check without getting current clamp meter to check over load is to confirm polarity, especially if RCD has small White earth lead they don't like it up 'em the wrong way, deary!!
regards SPARX
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