Changing old Outside Light to Motion Sensor 400W Spot Ask questions and find answers to many subjects relating to electrics and electrical work

[Jonniehack]

Hi all. Question about outside lights.

I have an old fashioned bulb light god awful thing just outside my back door which generates about as much light as a candle. I want to change this for a motion sensor 400w spot light.

I will need to mount the spotlight higher than where the light is now as it’s about level with the top of the back door.

The cable will not be long enough so, can I mount a IP65 junction box on the wall and feed the short cable into it, then run another length of cable up to the spot light and connect together?

Also will I need to encase the cable in something to protect from element or just tack to the wall of the house.

Thanks
Jonathan.

[Mr White]

So long as the junction box is suitable then yes you can.

I would suggest you use a box that comes with suitable cable glands, as making a hole / using just a knockout will let rain in. (Unless you "cheat" and use the knock outs at the bottom of the box and make a drip loop on the cable.)

As for the cable, plastic trunking is not meant for external use, PVC conduit IS meant for external use, but its primary reason is to give mechanical protection, so unless you plan on hitting the cable, I would suggest so long as the new cable is suitable for external use then mechanical protection need only be an option.

[ericmark]

There is a limit of 150W without planning permission, so personally I would use a smaller lamp. Think I have 8W LED in one house and 15W in other both ample for what I want. I have a 70 watt metal halide and never fitted it as too bright, would need sun glasses.

400W is rather OTT.

[Jonniehack]

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F390347462558

This is the item I’ve bought.
Never heard of the planning permission thing but will investigate.

Thank you for the advice, it does have to illuminate a large garden too, owing to changes we’ve made to the property.

[Mr White]

I personally do not recommend one floodlight to illuminate an area, I find two or more (lower wattage) is often better. A more even spread of light, and lower consumption.

[Jonniehack]

I personally do not recommend one floodlight to illuminate an area, I find two or more (lower wattage) is often better. A more even spread of light, and lower consumption.

Is it ok to “daisy chain” spot lights so if I have two lower wattage ones, daisychain them so they run off the same switch but there’s two with two separate motion sensors for two areas of the land?

[Mr White]

I have read what you have typed, but I do not understand the question.

You can "daisy chain" lights that are controlled by a switch.

Perhaps a drawing would help what you mean (You are there, I am not)

[ericmark]

Daisy chain in normally considered as a series connection as with Christmas tree lights and aircraft down lights, this is not really an option in your case, however in parallel yes you can have many lights from the same switch, we are limited by regulations to 16A for lighting, most switches rated either 5 or 20 amp and most lighting circuits protected with a 6A MCB or fuse, so total over 1000W so with 150W limit that is a fair few lamps, since on switch on lights use more power I would say 500W is a realistic limit for a 6A switch to be trouble free.

[Mr White]

What you say is "technically" true and correct, but do bear in mind Jonniehack is not an electrician, so his terminology will not be correct.