junction box light question

[robbie77]

Hi,

I know this is a simple question and I have done searches and looked at daigrams, probably too much so I am getting confused.

I have a very simple loft light to install. I was going to break the circuit between one light and the next, use a 4way junction box, two ports will be the entry and exit to the next light and the other two will supply the power to the switch and the light itself. Does this sound OK.

Reading an article it had a three way junction box that split the light circuit through 2 ports and the extra connected to another 4 way junction box that supplied a switch and lights? Would I only need to do this if I had more than one light?

Hope someone can clear this up for me!

Thanks

 

[1john]

you can use a 4 terminal 20Amp junction box as you described, if you want additional lights then just loop them from the 1st light if you want them to come on together.

 

[ban-all-sheds]

I think you might be confused between "ports" and "ways"?

You need a 4 terminal JB - L/N/E + switched live from the switch.

You need to be able to get 4 cables into it - the circuit in & out, the switch cable and the light cable.

Alternatively use a 3-terminal JB, take L&N to the switch and join the N for the light in a piece of choc-block inside the switch box.

 

[robbie77]

Thanks Guys.

I may aswel just get the 4 way 20 AMP junction boxes to keep it simpler but useful to know I can use a 3 way.

What is the best way to check which is the correct wire to break out of the three from the ceiling rose? Just try and trace the wire from light to light?

I think you might be confused between "ports" and "ways"?

Noted. As a profession I work with computers and networks will get my terms correct in the future!

 

[ban-all-sheds]

What is the best way to check which is the correct wire to break out of the three from the ceiling rose? Just try and trace the wire from light to light?

Just look at which terminals the cables are connected to - see the diagram(s) of rose wiring in the Wiki and For Reference topics. One will be obviously the switch cable, so you'd use either of the other two.

Or if there's a rose in a sensible place, and the terminals have room, you could dispense with the JB altogether - just take twin & earth from the rose to your switch. You can either join the neutral to the light in there, or with care open up the cable and not cut the neutral.