[FunkyMonkey]

Please can someone help. I want to replace an existing single 100W light point with a 4 x 50W spotlights. This is upstairs so I can easily get into the loft to get to the wiring.

I am handy at DIY, so I need to know what I need to do, regards the wiring, please, i.e.
Do I just instlal the new spotlights in series?
Are there any special precuations?
Any general advice.

Many thanks.

[Sonic67]

A bit involved this and there’s a few different ways of doing this.

I’ll ignore the Earth which is a bare wire that needs sleeving but that runs everywhere too.

On the lighting circuit you have a Live and Neutral coming in to the light and a live and neutral going off to the next light unless the light is the last one in the line.

You also have a two core (+ earth of course) cable that goes down to the switch. One of these cables is connected to the lives going in and out the other goes to the live of the light. When the switch is switched on the power goes from the lives through the switch and into the live of the bulb. The neutral of the bulb is connected to all the neutrals.

Note the cables used may be red and black cable. Red is live and black is neutral.

It may be that the cable going to the switch may be red and black also. Note that the black here is not neutral!!! It is a live cable.

Given that then you can fit a junction box in the loft with a live and neutral coming in. A live and neutral going out and a cable for the switch (Live Permanent and Live When Switched).

From the Live when switched and the neutral run a cable to the first spotlight. From that a cable to the next and so on.

This will mean you have a cable coming in and out to each spotlight which is a switched live and a neutral except your last light which will have just one cable coming in.

At your original junction box you have these connections: 1 Live Permanent, 2 Neutral, 3 Earth 4 Live when switched. You will have four cables coming from this junction box. One coming in (Live and Neutral) One going out unless the light is the last one (Live and Neutral) One going to the switch (Live and Live when switched) One going to your first spotlight (Live when switched and neutral).

At each spotlight is a cable coming in switched live and neutral (and earth) and one going out. Switched live and neutral (and earth) except the last one just has a cable coming in.

Remember at all points to connect all the earths together and sleeve them.

I hope all of this makes some sense. Read it through a few times till you are happy with it.

[smjxm09]

Remove any insulation around the light and don’t just separate it in case it creeps back.

[FunkyMonkey]

Is this in case I get wiring wrong, or is there an intrinsic reason for removing insulation?! Serious question. What with wiring being insulated itself, I'd have though it was safe for loft lagging to be against the wire.

(I picked up the spotlights today. They are spotlights as opposed to halogens. And 6 rated at 40W. Should be okay I guess).

Again, thanks for advice.

[owain_thomas]

Originally Posted by FunkyMonkey

Is this in case I get wiring wrong, or is there an intrinsic reason for removing insulation?! Serious question. What with wiring being insulated itself, I'd have though it was safe for loft lagging to be against the wire.

The reason is so that your loft insulation doesn't catch fire! halogens get pretty hot and need a decent amount of air around them to make sure they don't overheat and set things alight.

HTH

[davee]

Originally Posted by owain_thomas

The reason is so that your loft insulation doesn't catch fire! halogens get pretty hot and need a decent amount of air around them to make sure they don't overheat and set things alight.

HTH

Whoa, loft insulation should only be mineral wool or glass fibre which is totally non flammable. You shouldnt be using anything which may be combustible. The reason for removing the insulation from around the fitting is to ensure an airflow around the fitting so it nor the transformer if there is one doesnt overheat.

If in any doubt get a qualified electrician to do it for you.
You should be aware that Part P of the building regulations now requires anything apart from the simplest electrical works is notifiable to the LA or must be done by a qualified electrician.