Socket failed, what caused it?

[m0t]

I've got a double socket under the kitchen sink, it's actually an external weatherproof socket (BG WP22-01). We put that in 3 years ago because the last one failed when a bottle of carpet cleaner leaked in to the old one.

Plugged in to this is a 4 socket extension that feeds out of the side of the cupboard and is hung on the wall. The dishwasher and washing machine are plugged in to this.

Earlier we lost power to the dishwasher and washing machine (both running). The neon on the left socket that the extension is plugged in to had gone out and the switch no longer has any resistance, it's just loose. The other socket works fine.

I'm going to replace the unit but wanted to understand what failed and whether I need to buy a different type of socket this time round.

 

[cwhaley]

Sounds to me like you overloaded the extension lead. Remember it's only a 13a fuse (at most) protecting the wire on that lead, and if both appliances were running at their highest demand for power at the same time, then the fuse would have blown.

The washer has a large motor powering a drum, and the dishwasher (unless yours' has a hot water feed) has hungry heating elements to heat the water.

 

[Taylortwocities]

I'm going to replace the unit but wanted to understand what failed and whether I need to buy a different type of socket this time round.

You need to reconfigure your wiring. You need two single 13A sockets and for those two current-hungry appliances to be plugged directly to the sockets.
Have your favourite electrician install them for you, sited next to the WM & DW.
Note: Many double 13A sockets will fail over time if you run both appliances at the same time.

Do not use extension leads in this environment either.