Showers, RCDs, MCBs and Fuses

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I'm fitting a new shower in a house which currently only has old replacable fuses in its consumer unit. The wireing is fine (10mm) but I am not happy about just using the current fuse on the consumer unit so i have decided to wire in a separate unit with a 63A RCD and 50A MCB between the consumer unit and the shower. I was just wondering whether the best way to wire into the consumer unit is into the back of the existing fuse position and replace the fuse carrier without the fuse wire. Or is there a better way to do it - thanks in advance.
 
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The ONLY way you can do it is to split the tails in a henley block, and connect to that.

Have you made sure all main equipotential and supplementary bonds are in place?
 
The old rewireable fuseboards can only handle a max of 30amps per fuse way. So per RF's post split tails into your shower CU
 
The ONLY way you can do it is to split the tails in a henley block, and connect to that.

Have you made sure all main equipotential and supplementary bonds are in place?

Agreed! and 25mm Tails with 16mm Earth too!
 
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Why 25.00mm tails ??? 16.00mm tails are rated at 87amps even 10.00 mm tails would do.
 
Why 25.00mm tails ??? 16.00mm tails are rated at 87amps even 10.00 mm tails would do.
we are thinking that the company fuse is, or will be on next change, 100A.

the tails are exposed to the full current permitted by the company fuse.
 
Thanks for the quick replies. So you are suggesting that I split the tails before the existing CU using a service connector (Henley) block and then take the new feed into the RCD/MCB unit. I am planning to test the bonding, ELI etc before starting as it all looks pretty ancient. The house is also out in the sticks so may be a TT system hence my concerns about not having RCD protection on the shower.

Any further comments/observations and advice much appreciate

Cheers
 
Why 25.00mm tails ??? 16.00mm tails are rated at 87amps even 10.00 mm tails would do.
we are thinking that the company fuse is, or will be on next change, 100A.

the tails are exposed to the full current permitted by the company fuse.

If the OP is talking about a single way CU for the shower then I disagree, 10mm tails will be fine as the rating of the protective device for the shower will ultimately dictate the maximum current flowing through the 10mm tails.
 
Disagree all you like :) Reg 460-01-02 is quite clear.

I know about the single point of isolation. I've fitted many.

It's stated that 25mm tails are needed for connection to the shower CU from a henley block. 10mm is all that's needed. That's what I disagreed with.
It's nothing at all to do with 460-01-02 ;)

The ONLY way you can do it is to split the tails in a henley block, and connect to that.

Have you made sure all main equipotential and supplementary bonds are in place?

Agreed! and 25mm Tails with 16mm Earth too!
 
So I will also need to fit a main isolator switch prior to the Henley block - sounds reasonable to me !

:D
 

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