TT system tripping

[mannex]

I am working on a TT system and the electrics are tripping all the time, I have narrowed it down to the downstairs light circuit. Everytime when this light circuit is connected at the board and if I try to turn the oven (on the cooker circuit) or boil a kettle. ( ring main) it trips the electrics, but when the lightning circuit is disconnected everything works fine. I have done the insulation. Test and its ok am now running out of idea. Because it seems the lighting circuit is interfering with the cooker circuit and ring downstairs main. But how its happening........... I am hitting a brick wall.

Help please

I had to reposition a light switch on this light circuit and I have since double checked my wiring. The rcd is tripping not the mcb

 

[123]

In this case a water logged external light is unlikely as that would normally be present on all conductors wheras this has the classic symptoms of a N-E fault.

Not if its switched off (as is most likely)

 

[trev]

Not if its switched off (as is most likely)

In which conductor do we usually put switches and which ones still have a path back to the CU?

 

[mannex]

The readings were quite low around 264.... And the rcd 100ma is also the main switc on the consumer unit

 

[trev]

264 what mate?
264 ohms is bad, 264 Megohms is good. You need to be more specific, around x isn't really good enough for us to help you properly.
What's the back story to all this? You've been asked a couple of times.

 

[davesparks]

The readings were quite low around 264.... And the rcd 100ma is also the main switc on the consumer unit

What readings were they and what units?

Is that 264megohms insulation resistance?

 

[Octopus]

What does your boss suggest?

 

[Sintra]

The readings were quite low around 264.... And the rcd 100ma is also the main switc on the consumer unit

Have you checked for any erroneous connections between the lighting circuit and other circuits.

 

[mannex]

Its Omegaohms....... mybe there is a bad or cross connection am missing somewhere

 

[mannex]

Trev.. The stroy is I only repositioned the light switch but there is also a carpenter building a study wall so mybe there is a nail somewhere

 

[trev]

Let's go back to absolute first basics.
How long has this fault been showing itself? If everything has been working normally as it should then something has happened to make this fault appear, you need to find out if the customer has had any recent work done.
Were you testing the circuit properly? IE all conductors disconnected, lamps out, dimmers removed, switches in the on position, 2 ways operated etc.
Have you tested between circuits to eliminate cross connections?
What were the IR results L-N, L-E, N-E.
You've been asked a lot of questions on here that you haven't answered mate

 

[Octopus]

Trev.. The stroy is I only repositioned the light switch but there is also a carpenter building a study wall so mybe there is a nail somewhere

Which should show up when ir testing properly

 

[frontier219]

Its Omegaohms....... mybe there is a bad or cross connection am missing somewhere

Right. Omega is the symbol for Ohms, so that may have been a typo or you may be getting seriously confused with your terminology. Do you mean Ω or MΩ?

 

[trev]

Trev.. The stroy is I only repositioned the light switch but there is also a carpenter building a study wall so mybe there is a nail somewhere

Now we're starting to get somewhere. The back story I was on about was your role in all this mate, are you working under supervision as somewhere or other it says you're a trainee. Is this a job on the side?

 

[mannex]

The readings were quite low around 264.... And the rcd 100ma is also the main switc on the consumer unit

 

[telectrix]

264 what? cornflakes?