Second CU, where to mount and what cable to run?

ok - Just ran the calculator on TLC website (for what its worth) and it also came back as 10mm at 50 degrees, pulling 8kw over 14m is sufficient. I guess I'm being over cautions! like you have said @EFLImpudence normally that would be a 20a or 32A breaker for the whole floor + 6A lighting and be done!

Just concerned about it running in insulation in the future, and if i get round to solar not having to re-run cables!
 
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Thanks @AndyPRK the switch fuse is similar to what i had linked a couple of posts back, so thanks for confirming i'm on the right track!.

Re the 1st floor circuits, Both the first floor sockets and lights and loft sockets and lights are old wiring, with sockets in wrong places etc, so need to be redone, but I have no method of getting new twin and earth from the existing CU to the first floor hence the idea of putting a second CU in the loft and rewiring 1st floor and loft from there.
 
well you pick a first floor socket this is in the correct place, and suitable for loft access and run a cable upwards! (as a spur and change MCB to B25)

or have a look in the loft, you will find a point somewhere, where lots of cables run down. See if you want to use this route (and take up floor boards in that below room)
 
AndyPRK said:
well you pick a first floor socket this is in the correct place, and suitable for loft access and run a cable upwards! (as a spur and change MCB to B25)

or have a look in the loft, you will find a point somewhere, where lots of cables run down. See if you want to use this route (and take up floor boards in that below room)
Click to expand...

But the legs from the CU to the first floor also need to be replaced - or are you suggesting I use the existing red/black wires from the CU (slieved as blue/brown) to the first floor and then use blue/brown from there for the rest of the loop?
 
Don't know if this helps?

I have two consumer units, connected via 16mm SWA (3 core) around 16M, on the main CU it's protected by a C50 fuse.
Cable is weighty... Sparky said something to do with earth sizing.

The second CU is in the kitchen, running oven, micro, induction hob blah blah blah
 
Apologies for bringing this back up, so I'm going to use 6mm SWA, just wanted to check what components to use:

From Hendley to dual pole isolator - 16mm tail?

dual pole isolator to metal clad box - 16mm cable tail?

<what connector to use in the metal clad box? for L, N and E of 6mm?>

Metal Clad box to SWA with a gland.

Out of the wall - what's the best way to bend the wire to go up the wall?

Into the loft, back into a metal clad box with a gland.

metal clad box into CU - 16mm tail?

Do I need to use split RCD cu or can i go with a single? and does it need an isolator and RCD in the consumer unit?

What wire can i use from the block to isolator/into the metal clad box - i assume it needs to be double insulated hence the 16mm?

In which case the wiring is going from 16mm to 6mm back to 16mm?
 
Forgive me, but that is a rambling way of doing things and totally unsuitable.
If your still adamant running swa to the loft, then you simply need a 63a switchfuse with a 40a fuse fitted, 16mm tails and 10mm earth from switchfuse to henley blocks, then your 6mm swa will gland directly to the switchfuse.
At the top end, your swa will gland directly into the new METAL cu complete with main switch.
As for circuits, then either a main switch and dual rcd unit or main switch plus rcbo's, don't forget your calculations for spd to be fitted also.
 
muffking said:
You sound clued up, but this is not a DIY job. Should be done by an electrician and is notifiable.

Without reading all the way through I'd say your options here could be 16mm SWA from the Henley to the new board running no more than 63A.
Or work out the max demand for the loft and do a calc to work out cable size and come off a new breaker in the existing board. Say 10mm SWA of a 50A breaker if it checks out ok.
Click to expand...

How do you connect no doubt more than 3m of 16mm2 SWA to a Henley block?
 
FDA42446-9B96-4A00-BEE8-0F69F1165218.jpeg


Like that (y)
 
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