Upgrading a shower

3 Dec 2006
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United Kingdom
Hi, Im wanting to ugrade my old 8.5kw shower to a 10.5 kw shower. Several years ago I replaced the shower cable as it had been run outside the house in orange MICC cable with 10mm cable so the cable to the shower/consumer unit is ok and about 15m ish.

My fairly old wylex consumer unit, old brown looking thing with about 8 fuses to the left of the main switch and a 45 amp fuse to the right of the main switch.

Now I now Ive got to fit an enclosed 45amp rcd adjacent to the consumer unit but Im just wondering what fuse to take the shower from?

At the moment the shower is connected (via my new 10mm cable) to a 32mcb but the largest mcb that will fit the board is a 40 amp mcb, can i replace this fuse and holder with a 45 Cartridge fuse and carrier in place of the current 32amp mcb, will the bus bar in the cu be able to handle the increased load ??

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You should either put your tails in to a henley block then take a set of tails to your seperate shower 30ma RCD unit, and a set of tails to your existing consumer unit, make sure your earthing is up to scratch too, Alternatively you could double up at your consumer unit and take a set of tails from the live side of the isolator ( you will need to pull the main incoming fuse out for this though which will prob have a seal on it, or maybe it has been cut by someone else in the past ;) )

so the tails to the consumer unit, could that go to an existing space on the normal bus bar and fitted with a 45 amp cartridge fuse ?

PS about the seal bit, if someone else had cut it b4 i moved in, would the leccy board come and refit it for free ?
The only place in the CU you describe which will take a fuse larger than 30A is the one on its own to the right of the switch. The rest are 30A maximum (and are keyed as to not accept larger). You can add a additional consumer unit or you may wish to take the opportunity to have an electrician install a new CU.
Please note that the work you are doing is notifiable to LABC under part P of the building regs.
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Still not sure that the way to the right of the DP switch is OK for > 32A.

Will check with Wylex asap.

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