Installation of an electric shower

JanM · 30 Jun 2016 at 11:17

So our electric shower has died and I'm thinking about installing the new one myself as its a reasonably simple job to do.

Is it OK for me go ahead and install it or do I need to get a qualified tradesman?

TaKeN · 30 Jun 2016 at 11:24

I've changed ours at home before. It went fine, just make sure you isolate the power first.

You aren't messing with the original wiring and earthing, so I don't see any problems.

Hedge · 30 Jun 2016 at 11:27

I'd certainly do my own but I'm not sure everyone would think it's a good idea. It's a 20 minute job though.

JanM · 30 Jun 2016 at 11:29

Thanks for the conformation guys.

Yeah i've located the isolation for both the electric and the water. Thats pretty straight forward.
Only problem I can see is that the wiring is exiting from a different place through the wall when comparing to the new shower and there is no slack so I might have to extend and route that properly.

I've done loads of plumbing DIY stuff before and the electrics are pretty straight forward so i'm quite confident. If there is an issue the isolation's are there so I can
always call out a professional to fix it.

Woden · 30 Jun 2016 at 11:29

Can't see it being too big a job of you're already wired and plumbed for one.

Just remember to cut the power and water.

pepp77 · 30 Jun 2016 at 11:30

What KwH is the old shower and what is the new shower?
What diameter is the electric cable for the shower?

If the shower is 8.5KwH or higher then ensure the cable is 10mm diameter.

We recently swapped our shower from a 7.5 to an 8.5 and had to change the cable from a 6mm one to a 10mm one.

TaKeN · 30 Jun 2016 at 11:32

JanM said:
Thanks for the conformation.

Yeah i've located the isolation for both the electric and the water. Thats pretty straight forward.
Only problem I can see is that the wiring is exiting from a different place through the wall and there is no slack so I might have to extend and route that properly.

Are you able to source an identical replacement?

JanM · 30 Jun 2016 at 11:46

Hi I will check the cable diameter when I get home.
I think its a 10 diameter cable from memory.

The old shower was 8kw and the new is 9.5kw.

I am unable to find a like for like replacement as my old one is ancient.

MikeB · 30 Jun 2016 at 11:55

If going up in KW I would seriously recommend you getting a sparky to do this, they will check cable and fuse rating etc

Will Gill · 30 Jun 2016 at 12:04

MikeB said:
If going up in KW I would seriously recommend you getting a sparky to do this, they will check cable and fuse rating etc

This, the cabling needs to be up the task as does the protection for the system.

If it was a straight 8.8 to 8.5 swap then no probs do it yourself.

JanM · 30 Jun 2016 at 17:00

Hi guys,

The wire is 14mm diameter and the fuse is a Wylex NSB40 rated for 40 Amps.

The box for the shower says 9.8 kW (9.0kW 230v).

I think the fuse might be at the limits but the wire should be ok?

I think i'm chickening out and will get a sparky to do it if the fuse needs to be changed.

Adam_151 · 30 Jun 2016 at 17:48

How are you measuring the cable? We work on cross sectional area of cores and 4, 6, 10, 16 mm² are valid sizes

JanM · 30 Jun 2016 at 19:18

Yeah just realised I did the measurement wrong you cant just measure with a ruler. I'll see if I can find any print on the cable. Its been painted over.

If not a sparky is definitely going to be needed.

Doughnut007 · 30 Jun 2016 at 19:50

I may be wrong but if the appliance is located in a bathroom zone. Which as its a shower is likely then it is notifiable under building regs if you replace. You can call the council building control for free advise.

For the cost of getting it done right in an area where it will get wet pay the professional. Its not going to be expensive.

Adam_151 · 30 Jun 2016 at 20:57

JanM said:
Yeah just realised I did the measurement wrong you cant just measure with a ruler. I'll see if I can find any print on the cable. Its been painted over.

Is the earth core a single strand of copper or 7? Do you have a set of calipers?

AS_Platinum · 30 Jun 2016 at 21:03

With it being in Zone 1,
If it's like for like, my interpretation is that it is non notifiable work, due to maintenance. If however you are changing the load of the circuit, which is an alteration, then it is.

For your reference:
http://www.planningportal.gov.uk/uploads/br/br_pdf_ad_p_2013.pdf

JanM · 30 Jun 2016 at 21:07

I have a set of calipers but i'm going to see if I can get into the loft tomorrow so see if I can find some print on the wire.

If not I'll see if I can measure the each strand with the calipers but that will have to be at the weekend.

JanM · 30 Jun 2016 at 21:11

In the meantime i'll get a quote to see how much it'll be.

AS_Platinum · 30 Jun 2016 at 21:11

JanM said:
I have a set of calipers but i'm going to see if I can get into the loft tomorrow so see if I can find some print on the wire.

If not I'll see if I can measure the each strand with the calipers but that will have to be at the weekend.

Can you take a photo of the cable, with a reference point. Most sparks can just look at a cable and tell what size it is.

a1ex2001 · 30 Jun 2016 at 21:12

AS_Platinum said:
With it being in Zone 1,
If it's like for like, my interpretation is that it is non notifiable work, due to maintenance. If however you are changing the load of the circuit, which is an alteration, then it is.

For your reference:
http://www.planningportal.gov.uk/uploads/br/br_pdf_ad_p_2013.pdf

You are correct technically as this isn't a like for like swap it is part p notifiable, personally I wouldn't have a problem doing it if it was really straightforward but as your getting into lengthening cables and your unsure of the size of the current cable I'd call a pro to be sure. It's unlikely but Under spec cabling could burn your house down!