using 4 core NYMJ to wire Fluorescent lights

eiei0

Hi All

I was talking to an electrican and he was saying to use 4 core 1.5mm NYMJ to wire the lights in my shed,

can some one explain what the 4th core is needed for, he said something about using it as a switch wire, But I didn't like to ask too many questions.

plan is to have 3 light circuits one each side and then a few on the walls.

Thanks

DublinDilbert

I would imagine he wants to do the following:

Earth
Neutral
Perminant live (to switch)
Switched live (from switch)

m.j.w

You can do it using a 4 core or a 3 core nymj. If its easier to get from supply to the switch it can be done in a 3 core and if its easier to get from the supply to the lights first it can be done in 4 core.

The 4 core method would be

Brown from supply brought through each light to the common on the switch (In a connector, not connected into light). Blue looped to neutral in each light and earth looped to earth in each light. The black would be the switch wire coming from l1 on the switch and looped to live terminals in each light.

meercat

he possibly thought you would prefer 2 separate switches
1 for ceiling lights and 1 for wall lights

loop through all the cables to each fitting and then decide which connection to use for each fitting

blue neutral
green/yellow earth
brown live(ceiling lights)
black live(wall lights)

m.j.w

meercat wrote: »

he possibly thought you would prefer 2 separate switches
1 for ceiling lights and 1 for wall lights

loop through all the cables to each fitting and then decide which connection to use for each fitting

blue neutral
green/yellow earth
brown live(ceiling lights)
black live(wall lights)

Would ya not need a fifth core for a permanent supply to the switches to do that?

meercat

m.j.w wrote: »

meercat wrote: »

he possibly thought you would prefer 2 separate switches
1 for ceiling lights and 1 for wall lights

loop through all the cables to each fitting and then decide which connection to use for each fitting

blue neutral
green/yellow earth
brown live(ceiling lights)
black live(wall lights)

Would ya not need a fifth core for a permanent supply to the switches to do that?

Not really
Feed the switch first
Then take the nymj to the light points

Bruthal

m.j.w wrote: »

You can do it using a 4 core or a 3 core nymj. If its easier to get from supply to the switch it can be done in a 3 core and if its easier to get from the supply to the lights first it can be done in 4 core.

The 4 core method would be

Brown from supply brought through each light to the common on the switch (In a connector, not connected into light). Blue looped to neutral in each light and earth looped to earth in each light. The black would be the switch wire coming from l1 on the switch and looped to live terminals in each light.

This is one possible reason alright, where the cable goes though the lights before getting to the switch.

I did similar in a shed a a while back for someone. It had 2 x 2 way switches, one each end of shed, and a few flourescents so i used 5 core nymj from one switch, through the lights, and down to the other switch. Neutral and earth, 2 strappers connected straight through each light to second switch, and the last core was the switch wire back from second switch back to all the lights.

The extra cores mean only one cable is needed through all the lights. And a 3 core cable supplied the first switch.

Another reason would be as a second switch wire if you are going to have 2 seperate groups of lights to switch on and off with a 2 gang switch, so again, only 1 cable is needed.

eiei0

Thanks for all the replys,

I'd have to see it done to get a true idea but It sounds clear enough.

whats the going price for a roll of 3 and 4 core NYMJ.


Thanks