extending light circuit

[tonyboy]

Hello, I'd be grateful for any advise.

I want to add two or three wall lights and a shaver socket in a sort of dressing room area. There's a pre-existing unused 'spur' from the ceiling rose loop going to a 20amp JB. Can I use this to suppy ALL the extra fittings [via additional 20amp JB's].

I wondered if the same principle applies here as with the 13amp circuit - that the spur can only supply one additonal fitting and can not be extened on?

If the above is not acceptable - is it acceptable to extend the existing lighting circuit which currently serves six roses [small flat] to incorporate the new fittings?

I could just about access the circuit immediately above the ceiling rose. There's no access from above and I want to do minimal damage to the ceiling.
Would choc blocks be an acceptable means to connect to the existing cable?

Any comment gratefully received.

 

[Spark123]

I want to add two or three wall lights and a shaver socket in a sort of dressing room area. There's a pre-existing unused 'spur' from the ceiling rose loop going to a 20amp JB. Can I use this to suppy ALL the extra fittings [via additional 20amp JB's].

Providing the additional load does not exceed to rating of the circuit you can do it this way, how many watts of lighting is there on this circuit already?

I wondered if the same principle applies here as with the 13amp circuit - that the spur can only supply one additonal fitting and can not be extened on?

Nope, you'll be glad to know this rule only applies to "ring main" socket circuits.

 

[tonyboy]

Thanks Spark123 for speedy reply.

Sorry haven't worked out how to quote yet, but you ask about total wattage of light on existing. A quick count makes it 522watts.

The new lights would add 180 plus the shaver socket.

How is the rating of the whole circuit worked out? I'm afraid I don't know.

Thanks again

 

[Steve]

If you have a 6 amp MCB, the total load should not exceed 1380watts (6amps x 230volts). Anything over this and you risk tripping the MCB when all the lights are on. (Obviously you're unlikely to regularly have ALL the lights on, so a little leeway is allowed, but it is bad practise to grossly overload the circuit.)

 

[plugwash]

Obviously you're unlikely to regularly have ALL the lights on, so a little leeway is allowed

i think that has to be determined on a case by case basis, if each room has two or three seperate lighting systems for different moods or whatever then i'd probablly agree with you, if each room just has one group of lights then i most certainly wouldn't.

 

[Steve]

Well take an upstairs lighting circuit in a large house. 6 rooms. Each room has 200 watts of halogen lighting, and theres a couple of 150w security lights outside just below the fascia, on a PIR. IMO, this is not an unreasonable amount of lighting in a large house.

Thats 1500w in total. If you have all the lights on, it is overloaded. However, it is highly unlikely that mum, dad and the 2 kids will all be in their bedrooms, and someone in the 2 bathrooms, as well as someone in the home office!!! And someone outside waving at the PIR too!

However, if this were the case on the downstairs circuit, I would be concerned - it is more likely that all the lights will be on when entertaining etc.