Electrical Question

4 core connection-not so simple


Before I start, I am now getting an electrician in to fix my lights...

A couple of days ago I moved into a new build house. I wish to fit some outside security lights (4 in total). The wiring is already in place to the outside of property and then finished in a plastic cap type box to protect from weather.

The wire is 4 core, brown, black, grey and then a single in covers copper cable. I thought I could connect this, but obviously not as I cannot get light on.

I am now going to get electrician in to fit for me, but I am a curious person and wondered what each colour was and how it should have been fitted to a light with live, neutral and earth

2 Answers

Best Answer

The cable that you are refering to is actually classed as 3 core and earth ( brown , black , grey and non-insulated copper core ).
This is generally used as it allows for pir lighting to incorporate a permanent override which enables the light to remain on and by-passing the pir function.
This gives the light fitting the option of being used as a motion detecting security light or a standard switch operated light .
Colour coding of the cable should be as follows , but i have seen the colours reversed .
brown - live
black ( blue sleeving ) - neutral
grey ( brown sleeving ) - live / switchlive
If the cable cores are correctly identified at each end with the relevant colour sleeving to indicate the core function then technically any core can be used for any function, as long as its identified as doing so.
generally speaking if the cable core has the relevant colour sleeving at both ends

Answered 24th Jan 2014


Member since 28 Feb 2011

This type of scenario seems to be pre wired for a PIR light (Passive Infra Red sensor). Basically most PIR's involve a permanent live but its totally up to the person wiring it what colors they choose but they must clearly mark the cable to identify what cable does what with the use of sleeving or colored tape. Some electricians use black as the permanent live others use the brown. It doesn't really matter as long as its clearly identified with the use of brown sleeving. The only way to find out what does what is to go back to where the supply is coming from to identify what colours are doing what. In your case you only need 3 wires and are quite right all you require is a Live, Neutral and earth (copper single cable with no insulation but this must be covered when wired into the light with yellow and green sleeving). But this light requires a switch so you could go back to the switch and look there. If your not electrically minded i would definitely call upon an electrician as you might not understand how the switches are operating and can some times be a mind field. Hope this helps!

Answered 21st Sep 2013

Ecolek Wales Ltd

Member since 19 Sep 2013

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