Light Install in NR15

Replacing a light fitting sounds like a ten-minute job. Three things decide whether it is.

• Earth at the fitting. Lighting circuits wired before the mid-1960s often have no circuit protective conductor, and most metal fittings are Class I and need one. The options are a Class II double-insulated fitting, running a cpc to that point, or rewiring the lighting circuit.
• Fixing. A heavy pendant or chandelier goes into a joist or a purpose-made support. Plasterboard on its own will not hold it.
• Switching. One-way, two-way and intermediate arrangements look alike at the ceiling and wire up differently, and modern loop-at-switch wiring behaves nothing like the old three-plate ceiling rose.

Regulation 411.3.4 requires 30mA RCD protection for luminaires in domestic premises. In a bathroom the fitting also has to suit its zone, IPX4 as a minimum in zone 2 and higher close to the shower.

Adding a light point to an existing circuit outside a bathroom is not notifiable and gets a Minor Electrical Installation Works Certificate. A new lighting circuit is notifiable.

Buzz and flicker from LED lamps are almost always a dimmer mismatch. LEDs want a trailing-edge dimmer, and compatibility is lamp by lamp.