Shower Upgrade/Mcb,s/rcb

[silverfox]

Hi! All, Im upgrading to a 10.8kw electric shower.Ive replaced the old 6mm cable run for 10mm and fit a 45amp ceiling switch replacing the old 30amp.And am now at the C.U.stage.The existing C.U.is a WYLEX cat.No NN614 (about 20yrs old)with WYLEX MCBs TYPE2.Of which 1 30amp was dedicated to the old shower with no rcb.My questions are:
1)Can I get a suitable 45amp MCB to replace existing,and where from?
2)Do I also have to fit an RCB, and at what rating?
3)Or should I now think about replacing the C.U. for modern. (Comments appreciated)

 

[breezer]

you can get a 45 A wylex mcb form here

It is recomended that you have an RCD with a shower (80/ 100 A)

As you are getting an RCD you would be better off getting a new consumers unit with split load and RCD

 

[alexnic]

If you are considering replacing with a split load board then this site is worth looking at ...

http://www.tlc-direct.co.uk/Products/WYNHRS6604.html

 

[silverfox]

you can get a 45 A wylex mcb form here

It is recomended that you have an RCD with a shower (80/ 100 A)

As you are getting an RCD you would be better off getting a new consumers unit with split load and RCD

Thanks for the quick response and tips guys. But are you sure that the 45amp mcb (WYB45) plug in type for Wylex standard C.U.s, will fit my existing old Wylex NN c.u.? I prefer to go down this route if poss, than fit a new CU.

 

[breezer]

to quote the website "45 Amp Wylex Plug in MCB for wylex standard range of consumer units WYB45"

If you are not sure send them an email.

A split load consumers unit is although more expensive a far better option since it will hve an RCD, a life is priceless a consumers unit isnt.

 

[steveb]

The 45amp mcb quoted is for the older types of Wylex consumer units. It is designed as an upgrade from the old rewirable type of fuses and is not suitable for the NN range of consumer unit.

The NN consumer unit requires NB type mcb's. I'm pretty sure these are only available up to 40amps

 

[mattyy]

i am about to do the same job, and have been advised to use a 50 amp DP switch and 50 amp fuse, for a 10.8 kW shower?
I cant find a 50 amp rewireable. Can I use a 45 amp with 50 fuse wire (clearly labeled of course). Although I can find a supply of 45 or 50 amp fuse wire anywhere?

 

[breezer]

Sorry no you can not use 50 Amp fuse wire. 2 reasons.

1 Rewireable fuses are very slow in reacting.

2 If you did have a problem it would probably "explode" itself and everything around it.

Sorry but you would be much safer upgrading your consumers unit, then you could have an rcd as well.

 

[mattyy]

That probably explains whty you cant buy them, although B&Q sell the rewirable 45Amp holders. Unless they are pre wired you can't get the fuse wire, but then again if they blew once by the sound of it your CU would be in pieces!

OK so a new unit then - the link above looks like a good price, split load 6+6, with a 80Amp/30mAmp RCD - is this suitable? Other advice in this thread suggests RCD protection at 80/100 ?