Extending current Lighting in Loft

[VeeFourTee]

I currently have a spur from my upstairs Lighting circuit (via junction Box) for a Switch and Light in loft. It's T&E into Switch (Live to Com / Earth to Earth / Neutral to Choc Bloc) and then Switch to one Lamp Holder (Live L1 to Live / Neutral Choc Block to Neutral / Earth to Earth).

I would like to add two further lamp holders. Am I correct in assuming that I can just add another couple of Lamp Holders on to the existing Lamp Holder (in series) by connecting (via 1.0mm T&E) Live to Live, Neutral to Neutral & Earth to Earth each time?

Many thanks.

Richard

 

[electronicsuk]

I would like to add two further lamp holders. Am I correct in assuming that I can just add another couple of Lamp Holders on to the existing Lamp Holder (in series) by connecting (via 1.0mm T&E) Live to Live, Neutral to Neutral & Earth to Earth each time?

Yes, but this is not a series connection. Although 'daisy-chaining' one fitting to another may seem similar to a series circuit arrangement, the lamps will actually be in parallel.

 

[rebuke]

Which to clarify (as it may not be clear from electronicsuk's post), is exactly what you want - you want the light fittings to be in parallel, as otherwise they will not all be at full brightness, and if one blows, all of them will go out etc etc...

 

[VeeFourTee]

Thanks both. Think I understand. In other words, a Junction Box after the switch and then L, N & E to each Lamp Holder, so that one failed lamp won't affect the others?

Cheers.

Richard

 

[rebuke]

That would work, but you could just take a cable straight off the existing fitting, wiring L to L, N to N, and earth to earth. Either method would be wiring them in electrical parallel (if one bulb fails, the other will remain lit).

They'd only be wired in series if you did something such as live from the switch to L of first light fitting. N of first light fitting to L of second light fitting, N of second light fitting to N of supply (obviously, don't do this!).

 

[electronicsuk]

Thanks both. Think I understand. In other words, a Junction Box after the switch and then L, N & E to each Lamp Holder, so that one failed lamp won't affect t

You can do it that way, but it will look messy. The way you planned on wiring up the lights as per your original post was fine, you just need to make the distinction between series and parallel.

Using a junction box or linking L-L, N-N, E-E inside the fittings on the incoming/outgoing cables is a parallel circuit. The removal of one lamp will not cause the other lights on the circuit to go out.

On the other hand, if you were to use a single core cable and go from live supply to L on the first lampholder, then N on the first lampholder to L on the second, and then N on the second holder back to neutral supply, this would be a series circuit. Removal of one lamp would break the circuit, which is not what you want. Also (with two identical lamps) each one would only receive half of the supply voltage, so they would be dim.

 

[VeeFourTee]

Thanks both once again, for clarification and very clear explanations.

Regards.

Richard