Electric shower tripping out

[theroo]

Hi all,

I recently moved into a new house which has an electric shower. it was fine up until a few weeks ago when after 1-2 mins of use, the electric shower trips.

The RCD is NOT tripping, it's the fuse on the main fuse board that is.

It's a 10.5kw Triton shower, with a 40A RCD, and a 30A main board fuse. It's wired using what looks like 6mm cable.

I had two electrians come and look at it - first said I needed a Henly block, and the second said I needed to either change to 10mm cable or downgrade my shower to a 9.5kw as well as changing the 30A fuse to a 32A or 40A.

Which electrian is right?! All help is so so appreciated, I feel a bit lost and don't want to get ripped off!

 

[Steve]

A 10.5kw shower draws just over 45.6 amps. There's one answer. You need a 50 amp MCB, and a 63 amp capacity RCD, trip rating 30milliAmps.

The cable should to be 10mm² too. Most sparks will recommend this nowadays.

9.5kw > 41.3 amps = 45 amp OCPD
8.5kw > 36.9 amps = 40 amp OCPD
7.5kw > 32.6 amps = 32 or 40 amp OCPD (depends on design voltage)


Many OLDER consumer units will not take a 50 amp OCPD, so you may need an additional consumer unit installed for the shower (with henley blocks to link to the meter)

edited to add "older" cus

 

[theroo]

Thanks for the reply Crafty!

Excuse my lack of knowledge with this stuff, but what's an OCPD? Is it the actually fuse block in the consumer unit?

 

[Steve]

Thanks for the reply Crafty!

Excuse my lack of knowledge with this stuff, but what's an OCPD? Is it the actually fuse block in the consumer unit?

Over Current Protection Device.

The individual circuit fuse or Miniature Circuit Breaker in the consumer unit or fuse box.