Part P & Showers

[jacob]

It requires fitting and wiring by a competent person. Sorry to say it but the fact that you have to ask demonstrates that you are not qualified to.

This is self evident - but having asked the question and gathered the necessary information then one is then better qualified than before - which is also self evident.

I just installed a new Gainsborough 9.5kw shower in my new bathroom - following the useful instructions on the packet and having studied postings on this group. Nobody dead yet but we are all lovely and clean! As a matter of interest does anyone know what the showerer would experience if there was a major failure sufficient to trip the RCD?

[Uno Hoo!]

A shower of sparks ??? !!!

Kev

[Chipmunk]

[snip]

It depends on the path the leakage current took. All the electric showers I have seen use a metal heating chamber that is *well* bonded to the earth wire, and the metal pipework is probably well earthed too, thus, if the failure occurred inside the shower unit they would probably just experience a 'click' noise followed by either no water or cold water, depending on the unit. If for some hideously unfortunate reason the current went through the shower head, or through their body by some other means [maybe faulty control switches], RCDs aren't required to trip before 0.4 seconds at or even way _above_ their rated tripping current, so I wouldn't want to be them particularly.

[Stefek Zaba]

(All together now) Oh Yes They Are ;-)

According to the On-Site Guide, itself referring to Reg 713-13-01, the specs for an RCD spec'd to provide supplementary protection and with a nominal operating current of 30mA or less - and it's overwhelmingly likely that this is the spec a dedicated RCD will be made to - are that it opens in under 40ms - that's just two full mains cycles - for a current of 5 times nominal. And the trip times for other RCDs are to trip within 300ms, rather'n 400ms.

Nevertheless, your main point stands - sloppy installation practices can't be justified with an 'it's OK, it's all on an RCD which will pop if anything goes wrong'. Apart from anything else, RCDs don't mind at all if you cause an L to N flow from one hand to the other...

Stefek

[Chipmunk]

I stand corrected, eek I misplaced the decimal point. I plead ... umm.. braincell recycling due to being out of the UK for 5 years:-)

Yes, the 40ms for 'circuits supplying portable appliances' and 300ms for 'fixed appliances and wiring' sounds familiar.

Still, even 10mA leakage if I was in a shower would scare me.

[John Rumm]

I think you may be thinking of the required EEBADs disconnection times of under 0.4 for portabel appliances and 5 seconds for fixed. RCDs are supposed to be a whole lot quicker (unless time delayed!)