Loft conversion help?

[Electrician1972]

Looking at wiring a loft conversion , it’s a large loft and there will be a bathroom a bedroom and a walk in wardrobe , The sockets are wired from the loft but are in conduit to a junction box (have only located one junction box just now) I plan on taking my cables for sockets and lights to the main DB to be on there own circuits instead of tapping into any new ones , there will be 8 sockets and a some downlights , there are no spare circuit breakers in the main DB I am wondering can I use an existing mcb for say the upstairs sockets for my socket circit and make mine a radial circuit to have more space in the MCB and the Lights into the upstairs lights MCB as there will only be two switches to go to in the loft doing loop in at switches method . Any other ideas would be helpful but if I need to will just have to change Main DB to gain space for new circuits

 

[buzzlightyear]

Separate circuits for the loft from the CU.

 

[pc1966]

Extending the light circuit up a floor is not such a big deal as low load, etc.

Doubling up the sockets MCB is a bit nasty and not any of the recognised ways of doing it. If a CU change really is out of the question then I would say least-worst is to make the new sockets part of the existing upper floor ring final so it all measures end-end correctly, etc.

How old is the existing CU? Is it all OK for satisfactory EICR, etc, as it stands?

 

[telectrix]

can you not freeupawayor 2. e.g. by taking smokes off their own circuit and dabbing in with lights?

 

[pc1966]

What is the current CU size & layout? As @telectrix says it might be that some rearrangement of what else is in there would be far more satisfactory than doubling up on an existing sockets MCB.

 

[buzzlightyear]

there will be 8 sockets and a some downlights , there are no spare circuit breakers in the main DB I am wondering can I use an existing mcb for say the upstairs sockets for my socket

Not enough space new CU needed.

 

[telectrix]

buzz'ss ££££ eyeballs lit uplike Roger Rabbit.

 

[buzzlightyear]

It makes me laugh when can I do or not do, has Haugh green youresd to say make you mind up time. Me best not to get the agro new circuits or face a firing squad.

 

[telectrix]

It makes me laugh when can I do or not do, has Haugh green youresd to say make you mind up time. Me best not to get the agro new circuits or face a firing squad.

see youse back on form then. ?

 

[Electrician1972]

Extending the light circuit up a floor is not such a big deal as low load, etc.

Doubling up the sockets MCB is a bit nasty and not any of the recognised ways of doing it. If a CU change really is out of the question then I would say least-worst is to make the new sockets part of the existing upper floor ring final so it all measures end-end correctly, etc.

How old is the existing CU? Is it all OK for satisfactory EICR, etc, as it stands?

Yes all satisfactory as is just now , would running a cable from one of the socket MCBs to a fused spur say fit that beside CU then wire my sockets on a radial from the fused spur ?

 

[Mike Johnson]

My suggestion would be to run a 10/6mm into the loft and put in its own CU for the circuits off a decent size RCB/RCBO in the original CU.

 

[Vortigern]

you say bathroom are they having an electric shower in it?
If so split tails and extra box on the side from henleys.

 

[westward10]

Sounds like you are spending a few £s on this so a new consumer unit isn't surely going to tip the scales.

 

[telectrix]

Sounds like you are spending a few £s on this so a new consumer unit isn't surely going to tip the scales.

but not an easy one to show off to the neighbours, like look at this new bathroom,all these scintillating tiles , chrome shower head, and an auto flush bog. btw, here's my new CU stuck on the wall above the bog.

 

[Electrician1972]

My suggestion would be to run a 10/6mm into the loft and put in its own CU for the circuits off a decent size RCB/RCBO in the original CU.

Could I take a 10mm twin and earth from a 32A mcb to a new Sub CU with RCB protection at the Sub CU

 

[DPG]

Could I take a 10mm twin and earth from a 32A mcb to a new Sub CU with RCB protection at the Sub CU

But the twin and would need RCD protection?

 

[telectrix]

But the twin and would need RCD protection?

not if it's surface, e.g. inside airing cupboard, or trtunking upin a corner. ???

 

[DPG]

not if it's surface, e.g. inside airing cupboard, or trtunking upin a corner. ???

Well true. But I imagine at some point it will be buried. I wouldn't be happy with a loft conversion if the submain ran up the corner of the bedroom on trunking.

 

[telectrix]

Well true. But I imagine at some point it will be buried. I wouldn't be happy with a loft conversion if the submain ran up the corner of the bedroom on trunking.

why not? i frequently excercise by running up the bedroom wall. usually after 'er indoors has had new ideas.

 

[pc1966]

I guess the point is you can have T&E without RCD protection so long as it is not hidden < 50mm from a surface.

Feeding a CU off a 32A MCB works, but is not terribly good either as any big fault is likely to trip both the CU and the feed MCB, but again depending on what is needed that may or may not be a concern. Certainly I would be looking at a couple of RCBO in such a 2nd CU to reduce the chance of something on the sockets also taking out the lights.

But what is lacking here is the design aspect - what sort of load(s) are expected, etc. If it is just lights & sockets then a 32A feed is plenty, but if there is going to be an electric showed that suddenly looks small.

 

[Electrician1972]

I guess the point is you can have T&E without RCD protection so long as it is not hidden < 50mm from a surface.

Feeding a CU off a 32A MCB works, but is not terribly good either as any big fault is likely to trip both the CU and the feed MCB, but again depending on what is needed that may or may not be a concern. Certainly I would be looking at a couple of RCBO in such a 2nd CU to reduce the chance of something on the sockets also taking out the lights.

But what is lacking here is the design aspect - what sort of load(s) are expected, etc. If it is just lights & sockets then a 32A feed is plenty, but if there is going to be an electric showed that suddenly looks small.

No shower the shower will be thermostatic just 8 sockets , the only thing I can think is they have a walk in wardrobe where could possible be a hair dryer and other things like tht on at the same time , but I’m thinking taking a 10mm t+e to a sub consumer unit which will be fitted close by to the existing CU and won’t be buried fit an RCD protected 2way CU one sockets for sockets one for lights ?

 

[Mike Johnson]

Why not fit the sub CU in the loft, then if it trips the recommended RCBO's in the sub board its not a trip all the way downstairs to re-set.

 

[Electrician1972]

Why not fit the sub CU in the loft, then if it trips the recommended RCBO's in the sub board its not a trip all the way downstairs to re-set.

Why not fit the sub CU in the loft, then if it trips the recommended RCBO's in the sub board its not a trip all the way downstairs to re-set.

It’s a weird one mate would be ideal to do that but the existing CU sits on the ceiling in the hall which above that will be the middle of the bedroom upstairs so planning to fit the Sub Cu beside the existing one basically and run the circuits through the ceiling and under the new floor to where they need to go

 

[Electrician1972]

Why not fit the sub CU in the loft, then if it trips the recommended RCBO's in the sub board its not a trip all the way downstairs to re-set.

It’s a weird one mate would be ideal to do that but the existing CU sits on the ceiling in the hall which above that will be the middle of the bedroom upstairs so planning to fit the Sub Cu beside the existing one basically and run the circuits through the ceiling and under the new floor to where they need to go

 

[Mike Johnson]

Don't see the problem, its running one cable into the loft for the sub-board or running a few cables from the sub-board to the loft.

 

[DPG]

If it's only a few sockets and lights can't you just extend from upstairs RFC and lighting circuit? Does it need a submain and extra board?

 

[Mike Johnson]

If it's only a few sockets and lights can't you just extend from upstairs RFC and lighting circuit? Does it need a submain and extra board?

Don't be daft, thats far too sensible. ?

 

[Electrician1972]

Don't be daft, thats far too sensible. ?

The existing RFC and lighting circuit are run in conduit , let’s say it’s really really old and rusty so would rather just run some new circuits in

 

[Electrician1972]

Don't see the problem, its running one cable into the loft for the sub-board or running a few cables from the sub-board to the loft.

Take a 10mm to a sub board in the loft and just have my two circuits from an RCD board there

 

[buzzlightyear]

Take a 10mm to a sub board in the loft and just have my two circuits from an RCD board there

Yes take a 10mm to a sub board to the loft and just have the two circuits from the rcd board there. Echo, Echo.

 

[Mike Johnson]

My suggestion would be to run a 10/6mm into the loft and put in its own CU for the circuits off a decent size RCB/RCBO in the original CU.

Post 11 page 1. Echo, Echo, Echo, Echo, Echo

 

[DPG]

Post 11 page 1. Echo, Echo, Echo, Echo, Echo

No need for a submain and new dist board just for a couple of lights and a few sockets. Just extend upstairs lighting circuit and upstairs RFC. Why over complicate things?

 

[Electrician1972]

No need for a submain and new dist board just for a couple of lights and a few sockets. Just extend upstairs lighting circuit and upstairs RFC. Why over complicate things?

Like I stated existing circuuts are all in conduit and instead of tapping in to them I wish to run new socket and lighting circuits

 

[123]

Like I stated existing circuuts are all in conduit and instead of tapping in to them I wish to run new socket and lighting circuits

I'd sooner tap into them than bodge "new circuits" into a full consumer unit. If you want new circuits change consumer or add a new one. If not, tap into the existing lighting circuit and ring. If exisiting consumer unit doesn't have RCD protection, that's something else to deal with for the additions.