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Cable size


Alexphd1

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No quarantine here (yet), Aberdeen is 35 miles away.

I think it was being split before CU.

We have power coming into garage with a 12 way CU (which we are using just now) then another 12 way CU in the house for main house load. Garage CU over sized should have been a 6 way. 

Approx 12m between CU.

Edited by Alexphd1
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9 minutes ago, Alexphd1 said:

No quarantine here (yet), Aberdeen is 35 miles away.

I think it was being split before CU.

We have power coming into garage with a 12 way CU (which we are using just now) then another 12 way CU in the house for main house load. Garage CU over sized should have been a 6 way. 

Approx 12m between CU.

Then 16mm should be fine.  I run our whole house on 16mm over a 22 metre run.

 

It will need to be fed in the garage from a switch fuse with an 80A fuse.  Tails split with henley blocks if not already there (picture of what's in the garage please?)

 

You really really really want to avoid having to have an RCD for this in the garage.  So this will mean either SWA cable, or if you can route the cable on the surface or in trunking you could use twin and earth.

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Henley blocks into those tails, into a metal clad switch fuse with an 80A fuse, and then SWA between the switch-fuse and the house CU.

Not sure on 18th ed specifics, but my spark refused to run 16mm2 tails over 18m distance, even off an 80A fuse, mainly due to it being an all-electric dwelling ( so assume he worked out the loads and insisted on 25mm2 ).

Future plans for an EV(?) and can the EV charger be fed from the garage CU? If so, that would future proof the install against any adverse loads being added to the house CU  retrospectively.

Edited by Nickfromwales
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6 minutes ago, Alexphd1 said:

The little CU came from the solar pv installation.

Solar PV installer "set in his ways"

 

I might be inclined to suggest move the solar PV to the main garage CU to free up the space needed for the switch fuse.  Or even re purpose the solar PV CU.

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Splitting the meter tails and adding in a Henley block although pretty straight forward is firmly in the sparkies department. I just want run in the cable between so I can get the metal ducting covered up.

Yeah you guessed it with pv installer!

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16mm should be fine as long as fused at 80A Voltage drop won't be an issue over just 12 metres.

 

If it's steel trunking all the way then I would fit 16mm twin and earth and drop in a 16mm earth cable as well

 

Can you take the cover off the two garage CU's and post a picture inside?  and a picture of the house CU with the cover off?

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Guess what... sparkie never showed.

I am away to order 25mm cable but do I need 25mm for the earth or is 16mm enough.

Here's some photos of garage solar & normal CU. 

The 2nd CU in the house is empty at the moment, I didnt bother with photos of that.

20200821_125641.jpg

20200821_125414.jpg

20200821_125409.jpg

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16mm earth, but why not use 3-core and then problem solved? 
You’ll have to split the 25mm core between two of the 16mm max ( iirc ) earth bar connections to make it off. Assume spark will do this so won’t be your prob. 
Either that or run a 2-core and zip tie the separate 16mm earth along its length. They need to stay together btw. 

Edited by Nickfromwales
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