Grid switch fusing

[ASB1960]

I removed the grid switch 4 way with individual fuses below for drywalling and kitchen installation.

It was replaced yesterday. On turning on the dishwasher switch (nothing connected at the socket) the fuse blew with a bang and flash and tripped the mcb. (Twice).

I removed the faceplate and the 2 switch units. Nothing appeared untoward.

I was looking for a dead short. I checked continuity etc and couldn't find anything amiss.

I replaced the fuse and everything was then ok. Which seems odd.

It seemed as though there was somehow something very odd going on when I originally replaced the 2 x 4 gang panels in the back box.

Any suggestion as to what I should be looking for. The quartz splashbacks are due to be fitted soon and I don't want to be ripping them out!

 

[securespark]

A shorting issue at the socket controlled by the grid switch, or between the switch box and the socket controlled by it. Or maybe a short in the switch box itself.

 

[ASB1960]

I was trying to figure what on earth it might have been. Seemed odd that sumply screwing the switch panels into the back box could have caused some sort of short. Perhaps they were overtightened and this was the cause.

 

[pcaouolte]

I was trying to figure what on earth it might have been. Seemed odd that sumply screwing the switch panels into the back box could have caused some sort of short. Perhaps they were overtightened and this was the cause.

Did you catch the insulation of a conductor when you put the screw into the back box? Remove the faceplate again and check for damaged insulation.

 

[ASB1960]

I don't believe so. That would be very difficult with the location of the conductor, especially for the second switch. But it is certainly a bit cramped in the back box.

The power is all off anyway so will have a very close look when I take the plate off for the splashback fitting.

 

[AndyPRK]

plug something into the dishwasher socket and unsure it works

 

[ASB1960]

It does yes (when the power is on of course).