Power shower connection

[Junior]

I have a power shower (Separate cold and hot feed) all nicely plumbed in. Unfortunately the old unit ran off a 24v transformer plugged into a 3 pin socket in the loft.

What do I need to do to connect this new unit? It needs a 3amp fuse, min 4mm cable, and a 30mA RCD, but can I just take a spur off the ring main, or do I need to run new cable down to the consumer unit downstairs?

Thanks for any help, desperate to get this fixed, without the shower I'm starting to pong a bit........

 

[mapj1]

With 3A fuse you do not mean 4mm squared cable in theormal sense of '4mm cable', I presume they meant 4mm overall diameter or something equally daft. It can plug into or spur from the ring if a 3A fuse is OK, you could even run it off the existing lights pick-up via an RCD type spur box if that was easier.... how many watts really - it should say on the motor? a lot less than the 750 W the 3A fuse suggests I bet...

 

[plugwash]

umm 3A fuse and min 4mm cable doesn't seem to make much sense are you sure you read the instructions right (didn't miss a decimal point or something)

 

[securespark]

Still whatever the wattage, you will have to account for motor surges.

 

[Junior]

4mm square if not mechanically protected, 2.5mm2 if it is. it also asks for a double pole switch if this helps.

This seems to be ticking all the boxes for me at the moment:

http://www.screwfix.com/app/sfd/cat/pro.jsp?id=90026&ts=57941

So:

1. cable from junction box
2. RDC device as above
3. Where does the 3amp fuse come in? I see the rcd is rated at 63A, is it just a case of changing the fuse inside, or adding another fuse in the line?

Thanks for all the replies so far.

 

[Junior]

150watt max btw

 

[ban-all-sheds]

4mm square if not mechanically protected, 2.5mm2 if it is.

Those are the specs for supplementary equipotential bonding conductors - nothing to do with the supply for the pump. What exactly do the instructions say?

it also asks for a double pole switch if this helps.

I'm sure it does, but that doesn't have anything to do with the cable size...

This seems to be ticking all the boxes for me at the moment:

http://www.screwfix.com/app/sfd/cat/pro.jsp?id=90026&ts=57941[/QUOTE]
Is your installation not already RCD protected?

3. Where does the 3amp fuse come in? I see the rcd is rated at 63A, is it just a case of changing the fuse inside, or adding another fuse in the line?

There is no fuse, or any form of overcurrent protection in that device. 63A is the load it can safely switch off when it trips...

Where are you going to put it, i.e. what are you going to supply it from?

Re the 3A fuse - use a switched FCU with a 3A fuse in it - this will also provide the double-pole isolation you need.

BTW - are you familiar with the requirements of Part P of the Building Regulations regarding this work?

 

[Junior]

yes, your right, the text regarding cable size is in relation to bonding. POWER supply cable must have minimal cross section of 1mm square. I take it all back.......

As suggested above, I'll run it from a spur off the ring main, so this will use the plug in breaker at the CU, but I think I need a standalone RCD between the junction box and the switched FCU. Is this correct?

There is no electrical connections at the moment, the old transformer and cable have been removed.

I am aware with Part P is have to get an electrician to check over the work before I sell the place, is there anymore I need to do?

 

[ban-all-sheds]

As suggested above, I'll run it from a spur off the ring main, so this will use the plug in breaker at the CU, but I think I need a standalone RCD between the junction box and the switched FCU. Is this correct?

If your socket circuit doesn't already have RCD protection (and your use of the term "plug in breaker" means it probably doesn't), then yes. But a far neater solution would be an RCD FCU....

I am aware with Part P is have to get an electrician to check over the work before I sell the place, is there anymore I need to do?

Oh a great deal more than that.

1) The official stuff:

a - the relevant amendment to the Building Regulations: http://www.hmso.gov.uk/si/si2004/20043210.htm

b - links to the rest of the parts of the Building Regulations: http://www.odpm.gov.uk/stellent/groups/odpm_buildreg/documents/page/odpm_breg_600270.hcsp

c - The ODPM Guidance Document: http://www.odpm.gov.uk/stellent/groups/odpm_buildreg/documents/page/odpm_breg_033485.pdf

d - The ODPM Electrical Safety page: http://www.odpm.gov.uk/stellent/groups/odpm_buildreg/documents/divisionhomepage/br0054.hcsp

2) Other places for info, arguments, and lot of contradictory views, but the more you read the better feel you will get for it:

http://www.screwfix.com/talk/forum.jspa?forumID=23

http://www.iee.org/Forums/forum/index.cfm

you can search those fora for Part P, which unfortunately you cannot do here because of the useless search facility.

3) My unofficial this-is-your-position-in-a-nutshell:

This is "notifiable" work. Legally you must:

either submit a Building Notice to your LABC in advance, just like you would for any other type of work which came under the Building Regs

or have the work done by an electrician who is able to self-certify compliance with the Building Regulations.


OOI - where did you get the idea that Part P just meant you had to have an inspection done before you sell the house?

 

[Junior]

Could you point me in the direction of a suitable RCD FCU?

Jeez, my plumber was the one that told me about part P, the terms "New regs, start of this year" etc etc tend to get banded about a lot when i mention any electrical woes to my enlightened (Pardon the pun) friends.

So this basically rules out the DIY'er doing anything on his own without being qualified, similar to corgi I suppose?

 

[mapj1]

er no that's too general, and incidentally there is nothing to stop DIY gas if you can show that know what you are doing, you don't heve to be a CORGI member until you work for hire or reward. The electrical rules are in some ways less forgiving.

But there are still many things you can do without troubling the bean counters- and replace an existing shower pump with another, very similar one, might, at a push be one of them (like-for-like replacement is not notifiable) (and wiring not actually in a bathroom garden or kitchen)
Of course one could ask oneself how they will ever know or care if they are not told, whehter you did it last year or this. But I would be very foolish if I were to condone knowingly breaking the law.
However, I suspect as time goes by, more and more work will be appear to have been done at the very end of 2004.
However - a good read is needed, its not simple.

 

[ban-all-sheds]

Could you point me in the direction of a suitable RCD FCU?

http://www.tlc-direct.co.uk/Main_In...tected_Range/RCD_Protected_Range_2/index.html

http://www.screwfix.com/app/sfd/cat/pro.jsp?ts=24768&id=14770

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=41499&item=7516128083&rd=1&ssPageName=WDVW

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=41499&item=7516823400&rd=1&ssPageName=WDVW

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=41499&item=7516330814&rd=1&ssPageName=WDVW

 

[Junior]

providing I have enough ring main left to power the pc i'll let you know how i got on after the weekend.

One last thing, someone suggested wiring it into a 3 pin plug instead of going off a junction box, obviously with the rcd etc still, as I already have a socket in the loft, good/bad/ugly?

 

[Junior]

both shower and water pump being connected to these:

http://www.maplin.co.uk/Free_UK_Delivery/RCD_Plug_Adaptor_44049.htm

with 3 amp fuse and plugging into existing 3 pin in loft.........which is a spur off the lighting circuit.

 

[ban-all-sheds]

Do not put a socket on a lighting circuit....