10.8kw Shower trips MCB - Update

[williamglossop]

A family member has just moved into a newly renovated house. The entire gaff has been renovated- including an en suite.

The electric shower trips the mcb after a few minutes of being on.

Set up as follows:

. Mira Sport Max 10.8 kW shower.
. Seperate shower CU with 50 amp MCB
. 10mm cable - 15 meter (approx) run in 1st floor ceiling void.

I'm gonna nip round later to have a look - I have a clamp meter so ill check the current draw. The shower, 10 mm cable and CU are all new.

Any suggestions on what might cause MCB to trip? The RCD holds fine. It's just the MCB. Resetting it will hold for a minute, but then trios again. Only trips on HIGH setting and not on ECO mode.

I suspect the shower may be faulty.

 

[Taylortwocities]

I suspect the shower may be faulty.

10.8 kW is 47amp.
It doesnt happen often but possible MCB is out of spec. Any idea of the make? MCBs are cheap enough to swop out.

 

[blup]

A faulty breaker, get a sparky in to replace it.

Blup

 

[williamglossop]

I've been had a quick look.

Current flow is 42.7 amps when the shower is on full.

MCB is 50 amp Type B - Contactum branded

I noticed a slight crackle at bus bar. I've reseated it, torqued it up and the crackle has stopped.

Have not been able to get it to trip and ran it for 5 mins on full. But last night, It was constantly tripping the MCB - the first time it tripped the mcb held out for a few mins - subsequent trips were after less than a minute each time.

 

[Taylortwocities]

MCB not correctly fitted on bus bar could be the issue. I guess it’s a matter of seeing how it goes.
Maybe get a replacement MCB anyways.
Contactum is a reasonable budget maker, but nobody’s perfect.

 

[HERTS P&D]

Why would someone reovate a property and have an electric shower?

Andy

 

[chivers67]

Maybe no gas?

does sound like the MCB given it's no tripping more frequently...

 

[flameport]

Separate shower CU doesn't sound like much of a 'newly renovated house' either.

Even if no gas, an unvented cylinder with electric element(s) would have been a far better option.

 

[williamglossop]

The main bathroom is a normal thermostatic shower off combi. This shower is an en suite. The house has been rewired fully, but the ensuite came later and the main CU is full.

 

[williamglossop]

All appears well now..... must have been the bus bar/mcb connection.