10mm DI tails in henleys

[Matesrates]

Hi all. Just to see your opinions on this.
Started work on a local authority housing job. Wiring showers in highflats.

The spec is 2 way rcd enclosure with 40a mcb and the other way blanked off.
We are to use 10mm tails into henleys. 25mm tails in use for cu and 100a main fuse.
I say we should be using 25 as its 100a cutout. But foreman says its ok as it wont pull more than 40a.

I would agree with him if it was a 40a stand alone rcbo only. But the extra way leaves it open for they 10mms to be overloaded.

Thoughts please

 

[Leesparkykent]

I would say your foreman's right and if the spare way was to be used at some point the work should be carried out by an electrician who will assess the additional load and upgrade the tails if required.

 

[Flanders]

What Lee says

 

[7029 dave]

I would use maybe 16mm, no problem with sizes in this day an age being all modular, eg if it was an old 2 way wylex board, 45amp dp switch you would not get 16mm in let alone 25mm in the terminals.

 

[davesparks]

I would say that when working on a local authority job to a specification then I would follow the spec unless there was something obviously dangerous


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[westward10]

Whilst it is unlikely the spare way would be used for another 40A load you are never the less correct, the risk is there and it is placed there by the installer.

 

[GMES]

Agree with others, yes future proofing things is always a good practice but budgets and finances often dictate otherwise. as long as what you do complies and is safe then get on with it and move to the next one and the next one and the next one.

 

[rich.250]

10mm tails are fine. 6mm would be adequate for the load.
If it's a 63A rcd then in theory any self respecting installer would not put more than 20A on the spare anyway.
If your concerned just put a max load label on the CU.


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