Extension lights supplied from spur off ring main?

[24sevenv24]

Hi All

My single story extension is ready for first fix wiring. I am extending the ground floor ring main into the new room to supply the sockets however its going to be difficult to access the lighting circuit of the original house in order to extend it without ripping flooring up in various places.

Is it acceptable to spur of a ring main (via a 13a FCU) creating a radial circuit supplying lights? Total lighting load will be well under 1amp. I know its far from ideal as someone could shut off the lighting circuit expecting all lights to be shut off however the extension lights remain live, but if the circuit board and FCU was adequality labelled?

Cheers

 

[EFLImpudence]

Is it acceptable to spur of a ring main (via a 13a FCU) creating a radial circuit supplying lights?

Yes, perfectly acceptable. A 3A fuse would be more than adequate.

Total lighting load will be well under 1amp. I know its far from ideal as someone could shut off the lighting circuit expecting all lights to be shut off however the extension lights remain live, but if the circuit board and FCU was adequality labelled?

Yes, fine.

 

[ericmark]

The only problem would be if some one gets a shock from socket device tripping the RCD they would also be plunged into darkness.

However no one seems to worry about this, seen loads where sockets and lights on same RCD.

 

[JohnW2]

The only problem would be if some one gets a shock from socket device tripping the RCD they would also be plunged into darkness. .... However no one seems to worry about this,

They probably don't worry about it because it is a very improbable (hence very rare) event. I'm far from convinced that a significant number of people ever suffer electric shocks which cause an RCD to operate.

As I often report, over the past several years I've asked many groups, often large ones, and so far have only had a couple of reports (and even they are not necessarily convincing) - so,if there have been an appreciable number of such events, either the victims are nearly all dead (so much for RCDs ) or else they are, for some reason, not prepared to admit that it has happened to them.!

I would have absolutely no problem with what the OP proposes

 

[ebee]

In the days before RCDs were as prolific as nowadays it was not uncommon to find the odd light or two spurred from a ring in a limited area as a "cheap fix" and the chances of no sockets equals no lights either, was not ideal but not overly worried about either. It was seen as an acceptable solution in many cases. You could argue that for a circuit with RCDs involved then it might cause an additional issue due to increased likelihood of loss of lighting. Inside a medium to large room/area that might be a problem but inside say a large cupboard or a room described as say a larder then probably not much in practice.
Just ask yerself a few "What ifs?"

 

[flameport]

Is it acceptable to spur of a ring main (via a 13a FCU) creating a radial circuit supplying lights?

Electrically yes, but does seem rather rubbish for a new installation.

its going to be difficult to access the lighting circuit of the original house in order to extend it without ripping flooring up in various places.

Open up the ceiling instead. Much easier.

 

[EFLImpudence]

I somehow doubt an acceptable alternative for "without ripping floorboards up in various places" is "open up the ceiling".

It can always be altered should the floor/ceiling space be accessible in the future.

 

[ebee]

Well if you can get a floor up on the existing to run back to the mains that would be ideal.

I would say that wouldn`t I ? Where I live and was brung up (houses built around 1900s , cotton was King etc for the majority of housing stock, Tongue and grooved boards aplently). Cover them with tiles or laminate or replace with chipboards does bring about problems (chipboards often nailed not screws too).
Anyway, as said, you might consider opening up the ceiling below.
Or, as said, do your spur for now then convert it later when you might get easier access.
All good suggestions.
You got to factor in all the pros and cons.

 

[JohnW2]

.... , Tongue and grooved boards aplently). Cover them with tiles or laminate or replace with chipboards does bring about problems (chipboards often nailed not screws too).

... or, as I recently encountered to my considerable frustration, nailed and glued

Tongued and grooved flooring (even floorboards) is, in my opinion, the work of the devil in relation to any maintenance (in the widest senses)!

Kind Regards, John

 

[ebee]

NO - Tongue and grooved floorboarding is brill to get up and can often but not always be sawn to length half resting on a decent joist so creating an easy way to lay back down firmly without extra noggins etc and you almost back to what it originally was in terms of strength and appearance. Easy Peasy most of the time, especially seasoned timber. Proper flooring IMHO . Screw them back down for easy future access.

Must admit I will try every possible way to avoid needing a cut right on joist edge then have to put a noggin underneath, they have to be very firm to avoid dropping for years to come, I sometimes put an extra support under the next one or two boards each side of the one removed just to give more strength once down. I`ve cut millions, hundreds, thousands of floorboards to come up and fit back down. A proper floor is big old joists and T & G boarding, I hate it when the last person has taken some up (often, but not always, plumbers) then not fixed them down again, squeak/rattle/rock horribly.
PS if nailing, then 2.5 inch (65mm) ovals or lost heads not those weak 1.5 inch jobs but screws are better.

Chipboard is easy to lay, easier to get flat but can be a beggar to get up neatly and then you really do need battens underneath to prevent it bowing, crumbling at the edges over the years, and if it gets wet in a leak then often needs replacing, bad news.

Big hardware (ironmongers) to trades around here, the boss once told me as I asked for 4lbs of 2.5 inch ovals "You can`t ask for 2.5 inch you must ask for 65mm". I replied "Oh yes I can, I just did! and I may do, I can ask for whatever I want, I have no legal compulsion to ask for things in whatever units I want to or not, you must sell in SI units but nothing prevents you pricing in both so long as the imperial units are no larger and prominent than the SI units." I think I lost him on that one . An antithesis of those so called "Metric Martyrs ". Two extremes in ideology yet both quite wrong.

 

[JohnW2]

NO - Tongue and grooved floorboarding is brill to get up and can often but not always be sawn to length half resting on a decent joist so creating an easy way to lay back down firmly without extra noggins etc and you almost back to what it originally was in terms of strength and appearance. Easy Peasy most of the time, especially seasoned timber. Proper flooring IMHO . Screw them back down for easy future access.

T&G floorboards are certainly infinitely better than chipboard, but one still has to get pretty destructive to lift any of them after they have been fitted. From that point of view, traditional non-T&G boards are by far the best!

Chipboard is easy to lay, easier to get flat but can be a beggar to get up neatly and then you really do need battens underneath to prevent it bowing, crumbling at the edges over the years, and if it gets wet in a leak then often needs replacing, bad news.

Yes, much easier/quicker to lay than floorboards, but definitely "the work of the devil" if one ever needs to get under it. I have occasionally used it (including recently), not the least because of the price of floorboards these days, but I'm really only really happy doing it if any subsequent need to get under it is likely to be "someone else's problem"

Kind Regards, John