changing an outdoor floodlight

[johnny37]

I took my floodlight off the wall to check if there was a circuit problem and found that the wiring has burnt out. I am not very familiar with lighting circuits and I promise to get in an electrician if I cant do it! No jokes please.

The problem is:

The new floodlight has a live, neutral and earth terminal. I am fine with that, but there are two cables coming out of the wall. Do I simply connect both of them to the same terminals?

[tezestwing]

the old one probably had a override for the PIR circuit from a switch in doors and the new one only relies on the PIR you have to find the wires from the switch and only use the other 3 red black and earth, if you are not conversant with switching then you ought to get a sparky hth TEZ

[buildersmate]

No, Tez, the man says the new one has an earth terminal and yet the existing wiring is merely two wire. That means, whoever wired it, did not fit an earth wire. You simply can't fit the new one like this - if an earth connection is fitted to the unit, you must connect it. Either the existing burnt out unit was double insulated (shown by a square symbol inside a second square) and hence didn't need an earth or (more likely) it was incorrectly wired without an earth. Double-insulated appliances invariably have plastic cases - I have rarely seen one that wasn't. Because these devices get hot, the lighting chamber is always made of metal - which needs an earth connection.
You really need an electrician to advise you how to do this safely.

[johnny37]

Thanks guys. Sorry, I did not make myself clear. The two cables coming out of the wall are three core, earth, black and red. My limited knowledge of electrics tells me that one cable is for the light and the other is for the circuit. but I am not sure how to connect them.

I think I will get a man in. Its probably worth 50 quid!

[tezestwing]

now that you have given us a bit more info save your £50 and have a go DIY the red is positive and the black is negative the bare copper wire is the earth do not put any of these wires into a single connector together ( also sleeve the earth wire with yellow/green sleeve) bare the ends then put them into the apropriate connections as instructed on the new unit then mount it on the wall ,as instructed the PIR will do the rest hth Tez

[johnny37]

Thanks. The new floodilight only has one connector each for earth, negative and positive. There is no information about how to connect it back to the lighting circuit. Do I connect both cables to to the same connectors in the light? Will the circuit continue to work with the light off? BTW what is a PIR?

[tezestwing]

PIR is for passive infra red basically it picks up human heat movement in the dark, through opaque type lenses on the unit to work the security light, Johnny the new unit should explain this because it may need adjusting to the different on off times and light intensity,if on the other hand, if it doesn't have one and is as you say is a flood light then it will only work through a switch and only you know where that is maybe in the house or garage somewhere as for the connection you put the red cable into the positive connector and the black cable into the negative connector the earth goes into the remaining one hth Tez