By looping them through from the outlet in the ceiling: every spot gets its own live and neutral, carried on to the next. Not one after another in a chain, but side by side in parallel. GU10 spots run straight on 230 volts; a spot with a fixed built-in LED needs a driver in front of it.
Where you start: the outlet
Almost every ceiling already has an outlet: the spot where the previous light hung, with a junction box or a terminal block where the cable from the wall comes out. Two or three wires come out of it.
- Brown is the live, the switched wire coming from the switch.
- Blue is the neutral.
- Green and yellow is the earth, if it is there. In older homes it is regularly missing at a lighting outlet.
From that point you run a cable to the first spot, from the first to the second, and so on. One outlet feeds a whole row that way.
Looping through, not in series
Spots go in parallel: every spot gets the full 230 volts, and at each point you join live to live and neutral to neutral, carrying on to the next. That is called looping through.
Put them in series and the voltage divides across the spots, and nothing burns properly any more. With LED you then see spots glowing weakly or doing nothing at all.
So at each point you join three wires together: the incoming one, the outgoing one and the one from the spot itself. That is what a 3-way lever connector is for: wire in, lever down. Count on one connector per wire type per spot, so two per spot without earth and three with.
230 volts or a driver
Which spot you have decides whether anything has to go in between.
GU10 spots run on mains voltage. The GU10 socket connects straight to live and neutral, and the lamp screws in separately. No driver or transformer is involved. That is the practical advantage: if the lamp fails, you screw in a new one without touching the wiring. The difference between the two designs is in GU10 or integrated LED: what should you choose?
Spots with a fixed built-in LED need a driver to convert the mains voltage. That usually feeds several spots at once, and there is a limit: add up the wattages and stay under what the driver can handle. How many that is, is in How many LED spotlights can you put on one driver?, and which driver to choose in Which LED driver do you need?
What to do about earth
A fixture in a double insulated design, marked with the symbol of two squares inside each other, needs no earth. The double insulated GU10 socket falls under that.
If the spot does have an earth terminal, connect it. If there is no earth at the outlet, choose a spot that can do without. Leaving out an earth wire on a fixture that asks for one is not an option.
The switch and the dimmer
The switch sits before the outlet and breaks the live. Looping through changes nothing about that: it operates the whole row at once.
If you want to dim, a dimmer takes its place. A dimmer made for incandescent bulbs often has a minimum load that a few LED spots do not reach, and then you get flicker. Which one you need is in Which LED dimmer do you need for your spotlights?
Our spots are Triac dimmable, so leading edge phase control. That is the most common technique, but not the only one, and a dimmer using the wrong one will not work properly.
Before you go into the ceiling
Three things worth sorting out beforehand rather than halfway:
How many spots on one circuit. Mains voltage sets a limit on what may go on one circuit. With LED that limit is so high you rarely hit it at home, but with a long row it is worth checking: How many LED spotlights can go on one circuit?
The cut-out size. The hole you cut has to suit the spot, and that size differs per model. See What cut-out size do you need for recessed spotlights?
The spacing. Working it out before you cut saves holes that cannot be undone: How far apart should ceiling spotlights be?
When not to do it yourself
You may work on the installation in your own home, but it is still mains voltage and it has to meet the wiring regulations. Switch the circuit off at the consumer unit, not just the light switch, and check with a voltage tester that the wires are dead before you touch them.
Have an electrician do it if there is no outlet where you want the spots, if you cannot work out which wire is the live, or if there is no earth while your fixture asks for one. In a communal space it is not a job for a resident at all.
The range is at recessed spotlights, and the separate sockets and connectors at accessories.
Are recessed spotlights wired in series or in parallel?
In parallel. You loop them through from the outlet so every spot gets the full 230 volts. In series the voltage divides across the spots and nothing burns properly.
Do you need a driver for recessed spotlights?
Only for spots with a fixed built-in LED. GU10 spots run directly on mains voltage and need no driver or transformer.
Can you connect recessed spotlights to an existing outlet?
Yes, that is the normal way. From the junction box where the old light hung you run a cable to the first spot and on to the next from there.