Lighting circuit fault

[davemc]

Had a call from my sister in law earlier, saying all of the lights in her house went out last night so she checked to see if they'd tripped but the breaker was still at 'on'. All of the lights in the house are on one circuit, which isn't ideal but it's a small house and they generally use table lamps on an evening.
Her fella had a look in the ceiling rose and tested between live(constant) and earth and was getting 240v. Then tested between the switched live(off) and earth and was getting around 140v. She said there hasn't been any work done in the house lately so it wouldn't be a physical change in the wiring. I didn't have time to investigate myself but will nip round tomorrow.

Any ideas in the mean time?

 

[pushrod]

Mice chewing neutral? Sounds like continuity and insulation resistance tests are needed.

 

[nickblake]

140 volts between live and earth ,thats a neutral fault check all neutrals on the circuit till you find the fault ,get him to check between neutral and live