Electrical testing

Poppy9

If I put in a new shower in my bathroom to replace my old electric shower does it have to have an electrical certificate?

Existing wiring has been used it's just a new shower unit?

It's on it's own wiring as house was rewired 14 years ago.

vaio

If it's a like for like replacement then it's not notifyable under part P so no building regs approval needed.

But you should be issued with a minor works certificate which will confirm the rest of the circuit is up to scratch and safe.

Poppy9

vaio wrote: »

If it's a like for like replacement then it's not notifyable under part P so no building regs approval needed.

But you should be issued with a minor works certificate which will confirm the rest of the circuit is up to scratch and safe.

Thanks for this. Who issues a minor works certificate?

vaio

Poppy9 wrote: »

Thanks for this. Who issues a minor works certificate?

Your electrician should check & test the existing circuit to make sure it is in good condition and safe and then issue a minor works certificate to record the results.

macman

If you uprate the shower, then you may need to uprate the cable, depending on the circuit length and the KW rating of the shower.
If the cable was installed 14 years ago then it is almost certain that you need a heavier rating of cable, because modern showers are much more powerful than a few years ago.
Also you need an RCD fitting inline if it was not in the original installation (which 14 years ago it was unlikely to be).
What's the KW rating of the new shower and what is the approx length of cable run from the MCB?

Poppy9

Shower is on separate cable and you can switch just that off on the fuse box.

Original shower we had was a 8.5kw, new one is 9.5kw. When the house was rewired we were told, if I remember correctly, that the cabling allowed for future upgrading.

RCD I know we have one as electrician at the time told us he had installed but missed out the garage (which is detached) in error. Do you normally have more than one RCD? We use a petrol mower and garage only used for car hoover and strimmer normally.

mttylad

All the testing & KW issue's aside, from what I can gather if "you" replaced the shower
"like for like" then not only does it not need LABC notification then you won't need to issue a minor works certificate. That only comes into play if someone else did it for you.
I think....

baldelectrician

I have had this discussion with other sparks.

If direct replcement is done (a metal light switch or a shower for example) then - in my opinion - a test should be done by the electrician doing the work.

How else does one know the RCD connected will funcion satisfactorily, or there is an earth present (not just a wire that looks like an earth wire but is not effectively connected)

To sum up. If an electrician does it if should be tested. If it is DIY then it's up to the DIY'er to detemnine what should be done- as they are the person carrying out the work.

macman

Poppy9 wrote: »

Shower is on separate cable and you can switch just that off on the fuse box.

Original shower we had was a 8.5kw, new one is 9.5kw. When the house was rewired we were told, if I remember correctly, that the cabling allowed for future upgrading.

RCD I know we have one as electrician at the time told us he had installed but missed out the garage (which is detached) in error. Do you normally have more than one RCD? We use a petrol mower and garage only used for car hoover and strimmer normally.

Yes, it has to be on a separate circuit, anything else is against the regs and dangerous. But have you got an RCD protecting that particular circuit?-if not, you need one. It's not clear from your post if the shower circuit is off the main consumer unit, or a separate switchfuse unit.
A 9.5kw shower draws about 40 amps, so you need 10mm cable on that circuit. If the previous shower was 8.5kw it may have been wired in 6mm, depending on the length of the run and whether it's an open or covered run.
If you are in doubt about any of this then get a qualified electrician in. You can still do the actual mounting of the shower and the plumbing bits yourself if you want. With a high powered electric shower you really don't want to be taking any risks whatsoever.

Poppy9

We have a Wylex 8 switch consumer unit with RCD and the shower runs into this. There are separate buttons for each item like lights, sockets (upstairs/downstairs), cooker, shower & water heater. The shower one says NSB40. Does this mean something as the others have different numbers.

Not sure what is up in the attic. The main consumer unit is under the stairs and the bathroom is at the top of the stairs.

macman

Are you sure you have an RCD on that circuit and not just an MCB? It's not the same thing. It means that the RCD/MCB is rated at 40 amps, which is correct for a 8.5kw shower. but for 9.5kw you would need a 45A rating. If the isolator switch (pull cord?) is also 40A, this needs uprating too. As does the cable if it is not 10mm already.
1kw more may not seem a lot, but it's the same extra load as a one bar electric fire. Which is why you are advised to get an electrician in to ensure that the circuit can handle the load and has proper RCD protection.