Consumer Unit MCBs

[richy3333]

Do you have a building warrant or have BC confirmed you don’t need one For the size and usage of the building? I’d not sign your work off and no decent spark would either unless you had someone in from the beginning. If you have your 17th Ed then you’ll know it’s not a ring main ? Agree with all other comments.

 

[leebut]

Hi Everyone, I’m new to the forum and joined to gain more knowledge from you guys that are practicing electrical work. I studied 17th edition electrics at college a few years back and passed with great scores but never went on to use my electrical qualification in practice, I used my cabling skills and went into installing full office computer networks and config of the install bespoke to clients needs. My question is - I am currently building a summer house/office at home and have what you guys may think is a random question - I have a 4 bay consumer unit for the summer house 2x6a which will be 1 for internal and 1 for external lights, 1x 32a which will be for the ring main but there is a 16a MCB, having looked around on toolstation and Amazon most consumer units have a 16a MCB, I’m just wondering what I would use the 16a for? I am actually thinking of switching it out for another 32a MCB and creating a separate ring main circuit for a few outside double sockets to keep them on separate trips? Happy for any feedback that is constructive (I have seen plenty of forums where the response is - if you don’t know find an electrician) Thankyou in advance :c)

Hi

If it was me installing the summerhouse I’d be taking the 32amp breakers and swapping them for two 20amp and I’d be running two radial circuits instead one internal and one for the exterior socket if your only installing one external socket use the 16amp

I would throughly recommend you rethink what your putting into the consumer unit to comply with RCD protection I’d be installing individual RCBO’s in a board with a main switch and not an RCD incomer

Lastly you will be supplying the summer house with an 6mm armoured cable don’t take the earth from the house into the summerhouse terminate it outside the building or use a compression gland on the consumer unit end and install an earth rod connected to the consumer unit earth bar

 

[Electrics]

If you are modifying socket circuits, especially for outside you will have to change them for RCBOs.

Do you HAVE to or was that just the wording you used?

 

[GLENNSPARK]

Hi

If it was me installing the summerhouse I’d be taking the 32amp breakers and swapping them for two 20amp and I’d be running two radial circuits instead one internal and one for the exterior socket if your only installing one external socket use the 16amp

I would throughly recommend you rethink what your putting into the consumer unit to comply with RCD protection I’d be installing individual RCBO’s in a board with a main switch and not an RCD incomer

Lastly you will be supplying the summer house with an 6mm armoured cable don’t take the earth from the house into the summerhouse terminate it outside the building or use a compression gland on the consumer unit end and install an earth rod connected to the consumer unit earth bar

Oh dear.....here we go again...

"Extend"...? Or "Export"...? ?

 

[Vortigern]

Do you HAVE to

In that the modification would involve outside circuits, yes. And the fact a new circuit is being proposed by the op a new Ring Final Circuit.

 

[Electrics]

In that the modification would involve outside circuits, yes. And the fact a new circuit is being proposed by the op a new Ring Final Circuit.

Oh right i didn't know RCBO's were mandated. Good to know.

 

[loz2754]

Oh right i didn't know RCBO's were mandated. Good to know.

Only in the sense that any additional works must fully comply with BS7671 - so, new socket outlets must be RCD protected (either RCBO or RCCB).
Also any new wiring that is buried in a wall at a depth of less than 50mm added to an existing circuit must be RCD protected.
Any additions to a lighting circuit must be RCD protected. And so on....

 

[Electrics]

Only in the sense that any additional works must fully comply with BS7671 - so, new socket outlets must be RCD protected (either RCBO or RCCB).
Also any new wiring that is buried in a wall at a depth of less than 50mm added to an existing circuit must be RCD protected.
Any additions to a lighting circuit must be RCD protected. And so on....

Oh so RCBO's specifically AREN'T mandatory, but RCD protection is?

 

[DefyG]

Oh so RCBO's specifically AREN'T mandatory,

No

 

[Vortigern]

I think anyway, that new circuits/boards would automatically be RCBO for RCD protection as we have moved away from dual RCD boards in order to obviate the problem of everthing going off when one circuit is faulty.