I want to replace an existing 3 spot track in my kitchen with mains voltage halogen spotlights. When i have removed the existing light fitting there are 3 cable from the ceiling, 2 connect to the Neutral and the other is a twin core cable that one of the wires has a red insulation and is connected to the live on the light fitting but the other wire has no insulation and is terminated in to the electical connector but as the existing fitting does not require an earth it is a dead connection. As the new halogen light fitting requires to be earthed will a new earth cable have to run?

Phil, November 2006

you should earth! if a fault were to develop, ie,-insulation damaged on live and in contact with the metal of your mains halogen lights. this would make the metal casing live!! thus creating a potential for electrocution upon simply attempting to change a bulb. quiet simply you would act as the earth in this type of fault condition!!

sparky, January 2010

I wouldn't worry too much about earthing the halogen light. Your light will still work. Some lights and light switches don't have earthing facility. The earthing circuit is there to pick up any malfunction in the circuit, like a short-circuit and all the new BS electrical equipment should be earthed. It basically trips the MCB(mini circuit breaker) or RCD(residual current device), so that the current flow is stopped, in order to protect any persons from being electrocuted or property from taking fire. It is there for safety. You could look at it as a sentry that helps cut the energy supply in case of trouble. The lights will still work, even though the earth wires are not connected to the earth terminals. Lights without the earth path in place are not as dangerous as ring main circuits, where I would not advise you to leave the earth wire out. I hope this helps.

Michael, August 2008

Nope. Chances are that your existing bare cable is earth. If you're using grey twin cable the convention is you get red positive, black neg and bare = earth.

Rob, November 2006