Puzzling tripping problem.

[spagettilegs]

My garden lighting was tripping my MCB so I checked all the junction boxes outside.

I disconnected the live, neutral and earth connections in each junction box one by working away from the house and resetting the MCB until it tripped again.

So, I’ve found it’s tripping when one box is re-connected and not tripping on the one before. Ive concluded their must be an issue with the cable which is 5 core armoured between the two boxes and is buried underground in places.

I’ve done a continuity test on each of the cables and getting a continuous beep with a reading of 0.04 or thereabouts on each cable.

I’m at a bit perplexed as to what the problem is? If the integrity of each cable appears to be good, what might be causing the cable to trip?

Is there another test on the cables I should do? Is a positive continuity test a red herring?

Any pointers would be helpful.

Thanks

 

[James]

The fault could be in the box you are reconnecting or anything connected to it.
an insulation test will normally point you in the right direction.

 

[Intoelectrics]

As James said you need to do an insulation resistance test.