Faulty main isolator advice

[Simon_]

Visited a customer today saying that when he used the cooker the lights were flickering. Fault has only just developed and CU is approx 5 years old. Got there and CU is crackling and feels hot on the CU front. Isolated whole board and removed front. Tightened all connections powered up board and it's still crackling. Seemed to be quite a bit of plaster dust inside CU from work on the house a while ago that was also cleared. I'm thinking maybe its a faulty main isolator or tails are damaged? Tails are red and black and appear to be ok. Also checked tails to meter and all seems fine. Got to go back tomorrow. Advised to not power up CU at all.

 

[Guest123]

Are you sure the tails & busbars etc, are inside the switch terminals and not behind the actual terminals therby not clamped on at all???

 

[telectrix]

dust in either main switch or MCBs. try each MCB, one at a time. if you get the crackling on just 1 MCB, it's probably that one. if it's on several, then it could be dust in all of them, or in the main switch.

 

[Simon_]

I switched a few of them on and it did the same thing whether they were turned on or not. I will also check the busbars and switch terminals when I go back but it seems strange that if they were incorrectly terminated that it would take this long to cause problems.

 

[telectrix]

for what it costs, change the main switch, easiest option, after, as lenny suggests, checking all terminals, esp busbar.

 

[Simon_]

Ok thanks.

 

[topquark]

It's times like this a thermal camera (or a laser guided thermometer) comes in useful!

 

[Goody]

Take one of these with you when you next visit that place -> 400ML COMPRESSED AIR DUSTER IN A CAN PC SPRAY CLEANER | eBay

Cheers!

 

[Simon_]

Yeah I was just thinking about that actually.