Shower

[GU]

I had a 7kw shower and I've upgraded it to a 8.5kw shower. I've changed the wiring from 6mm to 10mm, the old shower unit had a seperate supply from the cu with a 30A fuse. My new shower is 40A but I can't use it at the moment as I've bought a RCD with a 40mcb, but I can't isolate the tails from the meter to the shower supply to change it to the RCD. Would it be possible to use the shower with the current fuse or would it definetly blow straight away? Also I'm thinking about cutting the seal on the main incoming fuse so I can change the shower supply over. I've just bought the house and it is the original wiring, so it's got to be 35 yrs old, but the shower supply was put in 23yrs ago I've worked it out. I could possible lie about the seal already being broken prior to moving in if anybody asks. The original shower supply fuse carrier was an mem, I've found it impossible to find a 40A mem fuse carrier although I'm sure it would be easy to find a 40A fuse. I would like to put in the RCD though as it cost me 40 quid.

 

[Steve]

I would like to put in the RCD though as it cost me 40 quid.

Not because it could save your life then.

 

[GU]

And of course it could save my life as well, well pointed out.

 

[flameport]

8500w / 230v = 36 amps. Not therefore suitable for a 30A fuse. It is unlikely the fuse would blow, however it would get hot, probably damaging the fuse holder and surrounding area.
A 40A fuse won't fit in a 30A holder either.

As always, the options are
1 - fit the new RCD/MCB and do the job properly.
2 - don't use the shower.

 

[GU]

Yeah that's what I'd worked out as well. I'm just gonna have to pull the main incoming fuse so I can fit the new rcd, until then you're right I can't use the shower.

 

[Newboy1996]

I fit electric meters every day and so do my work mates. I see no seals on cut-outs all the time, do you think we report people for this common sight? No.
Split the out going tails from meter into blocks. Run new 25mm cable from blocks back into your consumer unit and 10mm single core cable into the RCD mini CU.

http://www.tlc-direct.co.uk/Products/WYB40.html

40amp breaker for the old wylex board, if you ever needed it.

 

[flameport]

That Wylex item won't be any use because

The original shower supply fuse carrier was an mem

and a majority of Wylex boards are rated to 30A per way maximum anyway.

 

[GU]

When you say blocks, do you mean terminal blocks for 25mm cable, are they still plastic or special metal ones? I don't understand why I should run the new 25mm cable back to my cu as the supply for the shower is seperate and not having anything to do with my cu. The tails run from the meter into the old shower supply and I was just going to run them straight into the new rcd/cu. If this is wrong could you just explain it again. Sorry for being a pain and thanks for the info.

 

[Spark123]

He means Henley Blocks, but as I have pointed out on other parallel threads this work is notifiable to your LABC under part p of the building regs hence you would be better employing someone who is competent to do the work:
http://www.competentperson.co.uk/search.asp
Also consider having your CU replaced with a more modern one with more ways, have the shower connected into that.

 

[jockspark]

hi don't take this the wrong way but you need to get
a sparks in or it will end in tears

 

[ColJack]

GU post a photo and we can advise with a little more confidence...

 

[GU]

ok, I will do.

 

[GU]

The tails running from the meter to the shower supply are possibly 10mm, they are a lot smaller than the 25mm meter tails to the cu. I'm confused by newboys suggestion of how to do the job as the 10mm(I think) run straight from the meter to the shower supply. As the shower supply is 20+yrs old, Iwas going to run them into an rcd protected shower unit. 25mm tails run from the meter to the cu and have nothing to do with the shower supply. Thanks for the previous advice everyone.

 

[Spark123]

You would be better having a new consumer unit installed with enough ways to do the job.

 

[Newboy1996]

When you say blocks, do you mean terminal blocks for 25mm cable, are they still plastic or special metal ones? I don't understand why I should run the new 25mm cable back to my cu as the supply for the shower is seperate and not having anything to do with my cu. The tails run from the meter into the old shower supply and I was just going to run them straight into the new rcd/cu. If this is wrong could you just explain it again. Sorry for being a pain and thanks for the info.

The more question you ask the more it worrys me, as this end of the system is a potentially dangerous place to work.
There are less "wires/cables" to work with here, but danger to you more life threatening!
If you can't see the configuration of the system changes please leave work to someone else.