Lighting Circuit failure

[PhilB]

My client has half his upstairs lights working and half not. They are all on the same 5A fuse. His loft is boarded and so it's not easy to see the cable runs. What is the most likely cause? Is it likely to be a disconnected live or disconnected neutral in one of the ceiling roses that disconnects all the light units beyond or perhaps a problem in a junction box (loft lights were a later addition) that is hidden from view. I am reluctant start taking the very neatly loft boards up unnecessarily. Or is is something else?
Your thoughts would be welcome..

 

[WarrenG]

My client has half his upstairs lights working and half not. They are all on the same 5A fuse. His loft is boarded and so it's not easy to see the cable runs. What is the most likely cause? Is it likely to be a disconnected live or disconnected neutral in one of the ceiling roses that disconnects all the light units beyond or perhaps a problem in a junction box (loft lights were a later addition) that is hidden from view. I am reluctant start taking the very neatly loft boards up unnecessarily. Or is is something else?
Your thoughts would be welcome..

Could be multiple reasons and you are going to have to start somewhere. Have you checked for continuity at the none working lighting points?

 

[PhilB]

All the non-working have continuity. In any case a break there would only take one room out. My thoughts were that the disconnect could be at a rose which is working for its room but that the line that should move onto the next series of rooms has disconnected...

 

[JulesHurley]

Phil,

My first point is how do YOU know they are all working from the same fuse? How well do you know the installation?

Suggest unscrew all the upstairs the rose covers, and test for voltage across terminals.
a) Live to neutral at all roses,
b) Live to CPC at all roses.
c) Check all connections are tight
d) Conductors havn't broken at the rose,

and hope you find something easy - but in this weather, rodents will be a problem !!

 

[mrloy99]

All the non-working have continuity. In any case a break there would only take one room out. My thoughts were that the disconnect could be at a rose which is working for its room but that the line that should move onto the next series of rooms has disconnected...

try asking client if he knows when exactly he discovered the problem.was other work getting done at the time?was he up in the loft getting his xmas decorations down?changing a lightbulb?plumber working in loft,anything to help you get pointed in the right direction,even if it seems irrelevant. But as other poster says you need to be doing your testing at the roses with some kind of voltage meter and not a phase tester screwdriver which wouldn't show up a loose or broken neutral.