Lighting circuit still live after breaker turned off

[Luke105]

Lighting circuit. 3 rooms. I turned the breaker off and in the last room of the circuit I checked the light switch to make sure lights didn’t come on. They didn’t.

Anyway….the circuit still live at the fitting. The wire from the previous room loop.

I then turned the rcb off on the side of the board which that circuit is on and was then all dead.

What’s the probable cause here?

 

[James]

What were you using to test for voltage?
did it show 230v?

 

[Luke105]

What were you using to test for voltage?
did it show 230v?

Hi.

It’s reading 4 volts.

 

[James]

Hi.

It’s reading 4 volts.

4v between what and what? using what type of meter?

 

[Aaron b]

If your using a proper meter It's most likely that two circuits are linked but it could be incorrect polarity, the mcb only breaks the line conductor. rccbs are double pole so disconnects neutral too hence why James' questions are important.

 

[Luke105]

All sorted now. Thanks for responses

 

[James]

All sorted now. Thanks for responses

That is great news, what was the issue in the end?

 

[davesparks]

Hi.

It’s reading 4 volts.

Is that with a multimeter by any chance?

 

[Luke105]

That is great news, what was the issue in the end?

a case of reverse polarity