Light has no power from junction box

[ADringer]

Hi,

I recently put in a new light into an existing lighting circuit but am having an issue.

I cut into the circuit and put in a junction box. With this the current circuit still works and and all other lights work. However if I add a light to the new junction box it doesn't seem to work. I've tried three lights off the junction box incase it was the light but none have worked. I've also removed the switch incase that was the issue and wired that light directly to the circuit but still no luck.

Any ideas what the issue could be/what I could try?

Thanks

 

[PrenticeBoyofDerry]

Have you tested for voltage at the junction terminals, is the part of the circuit you have intersected, a supply feed, with neutral, live and earth, not a switch line that will contain permanent live, switch live and earth?
Don't be fooled by cable colours, how did you identify this circuit?
You are aware that any junction made must be left accessible for maintenance, inspection and repair. Unless the joint is made by maintenance free methods.

 

[ADringer]

It is a supply feed, I asked an electrician to have a look while he was here for something else.

These are downlights and the junction box can be pulled through so is accessible.

I've got a multimeter, what should I be looking for exactly?

Thanks.

 

[PrenticeBoyofDerry]

You need to be testing for AC voltage across live-earth, live-neutral and neutral-earth.
You would expect on an energised circuit around 240V on first two test and 0V on the third, but this is a live test so be careful.
If you have intersected on feed cable, you will need a switching arrangement.
if all this has been correctly done, you will be looking for loose connection or trapped insulation of the cores within terminals, providing you have voltage at the intersection.
Are the downlight lamps 240V or 12V?

 

[Taylortwocities]

I'll bet its a switch wire, and not what he thought at all.

Have a look at the lighting wiring diagrams in the WIKI and you'll understand whats going on.

 

[PrenticeBoyofDerry]

I'll bet its a switch wire, and not what he thought at all.

I have asked that question and it's a fair punt, I wonder what odds Ray Winston is offering?

 

[ADringer]

The downlights are 240v.

I was pretty confident that I got the feed wire but am pretty sure I am wrong now!
What's made it difficult is that I don't have access to the floorboards because of carpet/tiles and the ceiling has been plastered so can't go from that way.

If I can't find the feed easily I'll extend from the end of the radial.

 

[PrenticeBoyofDerry]

So you nor your alleged electrician have managed to identify the circuit correctly, but you cut in to the cable regardless, how did you manage to do any safe isolation without know what you were doing?