Additional Consumer Unit

[dunny123]

A large extension (utility, kitchen, cloakroom, dayroom, 2 beds, 2 ensuites plus garage)

The existing CU has no RCD.

Proposal: From meter tails install henley block and 60A switch fuse.

From switch fuse run 16sq mm 3 core SWA 7 Meters to IP65 box along outside wall.

Within IP65 box, connect via henley block and crimp to 16sq mm twin&earth (3Meters) and 16 sq mm earth cable to a new consumer unit to feed extension and garage. New consumer unit to be 5+5+2 "high Integrity" wylex. (one of the ways of main switch to feed smokes x 3 off 6A RCBO.

Any issues so far ?

 

[Spark123]

You could use a metal clad CU and run the SWA directly to it.

 

[dunny123]

You could use a metal clad CU and run the SWA directly to it.

Yes, thought about that its just that the T&E would be more "manageable" inside, in that it can be buried behind standard dot and dab dry wall and can be concealed up to and including CU (inside utility room)

PS. connecting the SWA to T&E inside box, I'm assuming i will need to a henley, or is there a "big" 60A connector strip or some other system I could use ?

 

[RF Lighting]

Or fit an adaptable box next to the CU and gland the SWA into that.

Alternatively, you could install split con cable, and again, take it directly to the new CU position.

You idea has an unnecessary joint. You want a new installation to have as few joints as physically possibly (i.e. none)

 

[dunny123]

Or fit an adaptable box next to the CU and gland the SWA into that.

Alternatively, you could install split con cable, and again, take it directly to the new CU position.

You idea has an unnecessary joint. You want a new installation to have as few joints as physically possibly (i.e. none)

Thanks, good points. But you don't have a problem with the 16mm tails ?

The way see it is better to diversify the additional load to an additional CU, and I would be protecting the long(ish) tails via 60A fuse.

 

[Spark123]

its just that the T&E would be more "manageable" inside, in that it can be buried behind standard dot and dab dry wall and can be concealed up to and including CU (inside utility room)

How deep is it to be burried? If less than 50mm then it will need 30mA RCD protection. SWA doesn't

 

[dunny123]

its just that the T&E would be more "manageable" inside, in that it can be buried behind standard dot and dab dry wall and can be concealed up to and including CU (inside utility room)

How deep is it to be burried? If less than 50mm then it will need 30mA RCD protection. SWA doesn't

Hmmmm, thats an interesting and valid point...does that mean all installations have an RCD between concealed meter tails < 50mm deep and the CU ?

 

[RF Lighting]

How many installations have concealed meter tails?

 

[Spark123]

If they are being done to the 17th edition - unprotected meter tails concealled in a wall or partition less than 50mm from any surface will need to be 30mA protected which immediately raises issues with section 314. Choosing another method of protection i.e. installed in an earthed metalic conduit, sufficient shielding to stop penetration from a screw/nail or selecting another cable type (SWA being one of these) means it won't need to be RCD protected.