Installing Electrics for 9.8kw shower

[GnzYza]

First of All Hello im new to this forum,

Im planning on installing a 9.8kw elec shower, please can you guys help me on the elecs side of things.
like mcb?? rcd??
cable size , etc, etc.
also rating of fuses, pull switches etc...
i have not ever done this before, but am a competent diy'er, but with instructions on the elec side i should be ok.

The bathroom is at the top of stairs and meter is at the bottom, can i run the cable straight up into loft along frame and down into bathroom rather chasing into walls or pulling up first floor??

Emphasisg on how to connect to electrical suppy and what changes i need would be a great help, any questions in order for you to give better instructions please fire away,

THANKS IN ADVANCE

 

[Steve]

do you know about part p? this work needs informing to local authority building control or be done by a competent registered person under part p.

that shower needs a 45amp MCB and pullswitch somewhere in the bathroom. Use 10mm² cable. Depending on what sort of fuse box you have at the moment, and whether there are any spare fuseways, you may need a new consumer unit. This is stuff DIYers shouldn't be messing with, new consumer units etc. Post a pic of your current consumer unit and we might be able to tell you if it will be able to support this load.

As for the route, can you use mini trunking? It sure looks better than running along skirting and frames and you can wallpaper/paint over it. Or you can run it outside the house along the wall, but you would need SWA (armoured cable) for this.

 

[blueblob]

//www.diynot.com/forums/viewtopic.php?t=36543

this post might be of some help to you if not get some custard...whee hee!!

 

[ban-all-sheds]

First of All Hello im new to this forum,

Im planning on installing a 9.8kw elec shower, please can you guys help me on the elecs side of things.

We certainly can, but first you should understand the legal position you are in regarding this work.

Here is the most recent version of my ongoing summary of DIY electrical work and the law, it contains links to legislation etc that you should follow and read:

//www.diynot.com/forums/viewtopic.php?p=234869#234869

Then you should get some reference material which will help you to adhere to the wiring regulations. This link has a list: //www.diynot.com/forums/viewtopic.php?p=75416#75416

From your question I'd say you probably need the first one, but if not you should get #s 2 - 4 - they should be on the shelf of anybody who wants to work on their electrics.

like mcb?? rcd??

Both of these are needed. There's some background material on types of MCB here, if you're interested. //www.diynot.com/forums/viewtopic.php?p=76467#76467

cable size , etc, etc.

also rating of fuses, pull switches etc...

You should read this //www.diynot.com/forums/viewtopic.php?p=81696#81696 to understand the relationship between load, cable size, MCB rating etc.

Also, this site has some very useful information: http://www.kevinboone.com/cableselection_web.pdf

While you wait for your copy of the Electricians Guide to arrive, you can get a head start by reading about the factors that affect cable capacities here: http://www.tlc-direct.co.uk/Book/4.3.1.htm

And here are a couple of useful on-line calculators for cable sizing:

http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

http://www.kevinboone.com/cablecalc.cgi

i have not ever done this before, but am a competent diy'er, but with instructions on the elec side i should be ok.

You should only do it with a firm understanding of everything involved - it's not a task you should undertake on the basis of following instructions but not knowing why you are doing things.

The bathroom is at the top of stairs and meter is at the bottom, can i run the cable straight up into loft along frame and down into bathroom rather chasing into walls or pulling up first floor??

Difficult to say without being there, but exposed cables are a bit naff.

The link above to the Electricians Guide will tell you about grouping and insulation factors, which may affect you, and you should also make yourself familiar with the rules on concealed cables:

http://www.niceic.org.uk/downloads/C5-43.pdf

http://www.niceic.org.uk/downloads/concealedcables.pdf

http://www.iee.org/Publish/WireRegs...les_concealed_in_thin_walls_or_partitions.pdf

Emphasisg on how to connect to electrical suppy and what changes i need would be a great help, any questions in order for you to give better instructions please fire away,

You also need to learn about bathroom zones:

http://www.niceic.org.uk/downloads/NL139supp.pdf

and what is required in terms of equipotential bonding:

http://www.niceic.org.uk/downloads/Earthing Bonding guide.pdf

http://www.niceic.org.uk/downloads/E169-9.pdf

and what is not required if you have plastic pipes:

http://www.iee.org/Publish/WireRegs/EarthingPlasticPipes.pdf

THANKS IN ADVANCE

No problem - glad to help.

PS - yes, you do have to

 

[GnzYza]

Thanks guys, i know its serious task for me and i will do it by the book.
mainly of course doind the elecs correct,
I will look into this and plan my approach to this.

there aren't any spare on the consumer unit, but what i have noticed is cooker one which i dont actually use because i got gas. this leads directly under the bath, i think the cabling passes the bath floor becuse its trunked from the ceiling almost directly below bathroom.

Can i use this somehow because the cables should be ok if its for a elec cooker??

i hope it is because it kind of takes most of the hard work out of the equation.

So i was thinking using this and making it a totally independent supply to shower and disregard outlet for cooker??

 

[GnzYza]

looks like a wylex consumer unit, with a cooker fuse i dont use because i have gas spare. Type b fuse, is this the mcb.
or will a new consumer unit be needed to accomodate the extra demand.

any suggestions appreciated, plus should i consider a RCD to avoid frying myself.

how does that incorporate into the line.

i know it may seem im playing with fire, but please rest assured i will not attempy anything until i am certain i understand.

 

[Steve]

if its an old black wylex one with rewireable fuses, this really should be changed before you install this shower. as far as i know, these were only made to accomodate 30 amp fuses, nothing higher like 45 amp MCBs. It might say on it "maximum rating 60amps" or something.

the shower needs feeding from a modern consumer unit. there are 2 ways of doing this.
a) the proper way: replace the old consumer unit with a nice shiny one with RCD etc, for the whole house.
b) more messy aproach: get the DNO to come and fit an isolator. split the meter tails, and fit a second consumer unit (2-way) with RCD protection and a 45Amp MCB for the shower.

if it is a white consumer unit, all may be fine (these are generally newer). can you possibly post a picture, or find a picture on the net?

 

[kai]

The colour doesn't really matter, it could be a metal fusebox or consumer unit - look for one marked BSEN60947 etc. and with a din-rail in it.

 

[GnzYza]

Hi guys, Okay its a white consumer unit no markings on it. but if i remove one of the circuit breakers. where the two prongs go into the unit, its marked 30 amp!!

So i guess its a 30 amp, new consumer unit looks like it??
any you recommend, or shall i just go and buy one with more spaces so to future proof it. oh and its got to have built in rcd??

if i get a elec to fit it in do you know how much they will charge??

Again eveyone thanks im starting to understand alot more, so if anything its definately an educational forum which is a good thing

 

[Steve]

was the circuit breaker you removed marked 30 amp by any chance? i'll bet if you remove a 5amp one, it says 5amp underneath it sounds like an old wylex board anyway, i would upgrade it now.

electrician may charge anything from £200 to £400 depending on where you live, and how long the job takes (every job is different). Beware of the £200 ones though - it may end up like mine:
click for horrible picture (incidentally, this was done bk in august, i just recieved the certificate from NICEIC or whoever the other day!)

 

[GnzYza]

Hi crafty,

yeah they all are marked differently, with the max on marked 30amp, so does that mean its no good??

The house was rewired but even that was a while ago.

looks like i will call an elec out to inspect and see if he suggests a new one's in order or not.

But defo mate you gotta be carefull init, i would normally use a recommendation.