Lighting & Fan Spur

[Gary67]

Hi there,

Currently installing a wetroom upstairs, and want to install,

(i) Halogen lights,
(ii) Exctraction fan with timer/humidistat
(iii) Supply power to the mixer unit on an Aqualisa Thermostatic shower. The processor power lead needs to be connected to a double
pole 3 amp fuse switched spur incorporated in the fixed wiring circuit.

As a plumber, I passed my 'Part P' at Gaswise in York, but have managed to forget most of it thru lack of use! So a little help would be appreciated.

I have good access in the loft, but don't seem to see any permanent live in the lighting roses.

Any help would be appreciated.

Many thanks
Gary

 

[Paul Barker]

If it's old property likely the lighting is fed from a large squarish JB in the loft. You should hopefully get a feed from there. Must be earthed lighting of course or you have to run a new feed.

Some chasing will be required to put a switched fuse spur on usually the outside wall of wetroom outside the room for the extractor and another for the shower electroncis.

In future both are liekly to require rcd protection so a small sub unit with a breaker for each and rcd fro all would be adviseable.

But first you have to work out the diversity before adding to the load on the existing lighting circuit to ensure it can be used, and then you have to work out maximum R1 + R2 for your new items and make sure volt drop is within spec. Likely your new items don't use much power and you will be fine but you must check. If you then discover a problem you either have to spur off the ring instead or run a new feed. Whichever I advise using an 30ma rcd protected circuit or make one. This is for ring main or new circuit options. Don't rcd protect the household lighting circuit.

Don't forget to bond to the cpc's

 

[Gary67]

Thanks for your reply Paul. There's no substitute for experience! Have done a diversity calculation, and there's plenty spare. As it's al oft conversion I have plenty of room for all the gubbins at a small loft access door on the same level as the wetroom. I'll be sure to let you know how I get on.

Gary