Shower regs

Bertington · May 27, 2015

Hello,

I have an 8.5kw electric shower I am replacing like for like. Upon reading the instructions the manufacturer stated the need for a RCD. The only RCD device I have in my system (2 bed house) is a 63a main RCD. This supplies all MCB's including the 40A shower MCB.

Is this adequate protection?

I know this isn't work that should be carried out by an unqualified person, however I have 8+ years experience as an electrical engineer so feel I can undertake this safely. I'm just not up to scratch with domestic wiring regs.

Thank you in advance

Marvo · May 27, 2015

Welcome to the forum Bertington.

I've moved this thread to the DIY area because the work is notifiable (I think) and you're not a sparky as such.

telectrix · May 27, 2015

as long as the existing RCD is a 30mA (trip current) then it complies. a like for like shower replacement is not, to my knowledge, notifiable. if you're sure that you are competent to do it, then go ahead.

uksparks · May 27, 2015

I wouldn't notify it if it's a swap,

Bertington · May 27, 2015

Thanks a lot. It seems like a bit of a grey area with regards to whether the RCD needs to be dedicated to the shower or not. Shower is fitted and working fine. I didn't electrocute myself so you can all sleep easy

Darkwood · May 27, 2015

No its not needed to be dedicated as long as the RCD covers the shower circuit then as others have said it's fine, easy to confirm by tripping rcd and seeing if shower works.

telectrix · May 27, 2015

and it might be worthwhile to check the shower isolator, esp. if it's a pull cord type for signs of burnt terminations.

Marvo · May 28, 2015

Given that a bathroom is considered a special location I'd suggest ramp testing the RCD before deciding whether it's okay to use as protection. Also the RCD as a main will see the cumulative leakage across the entire installation so there's a higher chance of it being an annoyance when it trips.

Darkwood · May 28, 2015

Marvo said:
Given that a bathroom is considered a special location I'd suggest ramp testing the RCD before deciding whether it's okay to use as protection. Also the RCD as a main will see the cumulative leakage across the entire installation so there's a higher chance of it being an annoyance when it trips.

As a DIY doing this on his own home he will also have the responsibility to periodically test the rcd at the CU and ensure his electrics are safe and sound with a full inspection and testing report, if he does this the added risks of doing such a job are minimal .... but how many have their electrics routinely inspected is a different matter altogether... but a good point raised by you as assumption is the mother of all screw ups! for want of a better word.

Bertington · May 28, 2015

I agree. I have tested the RCD using the trip switch. I assume this is considered a complete test? Or should I stick my fingers in a plug socket just to be sure?

Darkwood · May 28, 2015

If we were to do the tests we use measuring equipment to ensure the rcd works at the correct leakage and in a specified time to ensure it meets safety guidelines... the test button will only prove it operates and will not prove it complies .. hence Marvo's post...

As an homeowner its down to you to ensure you Electrics are tested and checked and this requires professional testing gear (Not the volt stick or multimeter from B&Q) ... an example to highlight the risks of DIY ..consider the earth wire to the shower is broken or damaged along its route now you see an earth at the shower and connect it up and get a warm feeling of achievment but in reality you have connected a circuit that has a broken or high resistance earth that in a fault could be very dangerous ... now if your rcd is functional and tests with the proper test equipment then even in the above scenario you still hav a good degree of personal protection.

When is an earth wire not an earth wire .... when you haven't tested it!

Bertington · May 28, 2015

What equipment is to test the earth at the shower? I have a martindale pat tester. Can I do it with that?

Darkwood · May 29, 2015

You can test the earth with knowledge of the limitation values with a standard multimeter but you still need to do other tests to confirm the integrity of the cable etc ...

As I said if a qualified Electrician changed it for you he would have to ensure the integrity of the circuit as well as the earthing and the requirements of the earth bonding to gas and water (in domestic) ... something you don't ever think about when doing DIY ... the range of meters or a combined meter that does these test cost several hundred pounds ..so no a PAT tester will not suffice.