New consumer unit perhaps

[foxeye1]

Please accept my apologies if this topic has already been discussed.

I have a 'modern' consumer unit with micro circuit breakers, not fuse wire. All circuits have been used for lighting, cooker, ring mains etc., and I now want to fit a new electric shower which I know needs a seperate circuit. Question is, do I need a complete new consumer unit, or can I somehow 'extend' the existing one?

I shall NOT be doing this task myself as it is way beyond my capabilities, but I would be grateful for simple advice, the emphasis being on simple as you have a complete moron at this end! Thank you all for your efforts. I and no doubt many others really do appreciate your advice. Thank you.

Steve Harrison

 

[andy]

if there is a spare space in CU then it can be added. if not, might be easier splitting the tails and adding a mini CU. altho, is it RCD protected?

 

[Damocles]

As andrew pointed out, are there spaces on the front fitted with blank plates instead of breakers? If so, then you put in extra breakers in these spaces.

Assuming there are not, then you have two choices. Replace the whole CU with a longer one with room for more breakers, or add a second one.

In general people tend to prefer keeping everything in one box, but there are some advantages to having two. You do not have to switch off everything when you are working on the electrics!

Also as mentioned, you could add a second incorporating RCD. An rcd or the equivalent individual RCBO replacement breakers gives a very sensitive reaction to cut off the power if there is a short from live to earth. It is now recomended for sockets and especially anything outside or where it might get wet.

Modern CU are frequently 'split load'. Half is protected by a RCD, the othe just by a main switch. It is not helpful to have your lighting circuits on the same RCD as the sockets, since a fault in the sockets would also switch off the lights.

Or you can get a small CU with just an RCD switch and mcb, intended for adding something like a shower. But only go this way if you are quite sure you will never want to add anything else

 

[plugwash]

another possibility is to remove the two lighting cuircuits from the CU and run them from a pair of 5A fuse connection units connected to say a 20A breaker.

 

[ban-all-sheds]

Which would have the added benefit of stopping the blown-bulb-tripped-MCB problem...

 

[securespark]

Uh?

 

[ban-all-sheds]

The fuses won't blow on the surge when a lamp fails as they are too slow, and the 20A breaker won't trip as it isn't sensitive enough.

 

[foxeye1]

Dear All,

Thank you all very much for taking the time and trouble to answer my question. Your assistance is very much appreciated. As there are no spare slots on my CU, I think a whole new unit will be the most sensible answer, so I shall be contacting an electrician to do the work for me.

Your advice however has allowed me to make an informed decision prior to being subjected to a 'sales pitch'. Thank you once again,

Best wishes,

Steve Harrison