Strange fault.

[securespark]

Went to a property with first floor lighting fault. Tripping mcb.

Lamps out, disconnected feed & meggered everything. Fine.

Reset breaker. Stays on for 20mins. Leaves.

Trips overnight...

Returns next day. Meggers everything. Finds possible cable down between L & E. Disconnects & resets breaker. Stays on for 35mins. Leaves, scratching head.

Trips again overnight.

Customer says it tripped when turning landing light off from the downstairs switch.

Can anyone complete the story?

 

[VanSolo]

Fault between one of the straps and cpc. Nail in switch drop?

 

[Spark123]

New switch and someone muddled up the wires?
Using the CPC from a 2+e for a live conductor?

 

[securespark]

Van wins it!

There were not one, but TWO piccy hooks in the strapper cable between the landing switches, shorting out L1 to earth but only intermittently...

I put my megger between L1 & one of the piccy hooks & got a 0.00 reading!!



According to customer the hooks've been in 12 years...

 

[VanSolo]

Got done with that one when I was starting out. Just couldn't work out how the fuse went when the light was switched off. took hours before the penny dropped. And about a foot and a half of 5amp fuse wire! Thank god for mcbs

 

[securespark]

Me too... although it took until the end of my time there on the last visit for the customer to tell me that the breaker only tripped when the light was switched off from the downstairs switch.

As for the yards of fusewire, whenever I nvestigate a fault on lighting, I swap it for a breaker temporarily.

 

[VanSolo]

Yep, got a 6amp one in my test kit. At the time I worked for the tightest man on the planet. Surprised he didn't take the price of the fuse wire out of my wages.