Fixing a dishwasher all wrong

Presumably then the faulty socket had hardly ever had its switch operated ?

I had the same thing with a built in oven that failed due to a faulty socket switch. Which was *never* used as it is behind the oven.

Yup, it has probably been left switched on since 2017 since it was installed. No signed of heat damage or discolouring on the plug itself - so it was just a poor contact in the switch rather than the socket contacts. Probably been like that since new.

It does advocate for the use of unswitched sockets in places where they will never be used. My default has always been that a switch is a good idea, but I can see a good argument in this case.

Was there a switch elsewhere to isolate the dishwasher?

Theo

I've had (a couple of times in the last 40 years) situations where the switches on 13A sockets that feed high load appliances, have 'fused' into the on position. These have been where the switch has been in the on position for years and years and years !

Never had a problem expose what had happened though. I'd have had the dishwasher in bits too !

Yup, had I installed it from scratch I would have been an unswitched socket fed from a plate switch above the counter.

However this was installed when I found the Kitchin ring had been broken (probably kitchen fitters used by previous owners!), and it was a handy place to put the two halves back together again.

Retrofitting a separate switch in a tiled wall was going to be a pain.

Having said that, you still have a switch even then, and the same problem could occur. (chances are a above counter switch would never have been switched off either)

Nope...

At some point in the nearish future I will probably redo the kitchen and utility room - so that will be a chance to do it better.

I have one of those - it's probably where some previous owner plugged in the kettle. The other possibility is they were in the habit of switching it off under load, and the contacts have welded.

Of course some muppet decided to grout in all the electrical fittings, so it's impossible to remove without half the tiling :-(

Theo

Grout will normally dissolve under application of brick acid or any angle grinder/dremelly sort of tool

Carbide or diamond grit edge saw in a multimaster is the cleanest and least destructive way of cutting out grout lines and tiles I have found.

I don't see why an unused switch would be especially liable to failure.

I have the following arrangement for all my undercounter kitchen appliances.

A switched neon FCU above the worktop and then a drop cable from the switched neon FCU down to a unswithced single 13A socket under the counter.

So I have 4 switched neon FCUs in the kitchen for a freezer, a fridge, a dishwasher and a washing machine.

So the switrch above the counter gets excercised (for defrosting freezer and cleaning fridge) and there is no hidden switches under the worktops to become an issue.

We've got a Samsung American style fridge/freezer, that sits inside an alcove.  I didn't want any faffing about regarding being able to kill the power to it, or for any failure (such as the fuse in the plug blowing) that would require dragging it out of that gap. The other side of the rear alcove wall is the Utility Room counter-top, so there's a simple outlet plate terminal block that the fridge's flex is connected to, which is fed through the wall from an FCU on the Utility Room wall.

Mrs C raised concern that 'someone' might accidentality switch it off while grappling about in the dark in there !  Well, it's 'her' room, I'm only really allowed entry when there's some sort of appliance failure etc, so go figure !  It's suitably Dymo Labelled of course.

Possibly because the wiping action is not constantly cleaning the contacts. Oxidation of switch contacts coupled with expansion/contraction as the contacts heat/cool with changing loads may cause some arcing.

In a kitchen over a period of many years the fine mist of oil/fat from cooking gets into every crevice including the gaps between a socket faceplate and the wall. I recently took off a (unswitched) socket that a fridge has been plugged into for the past 20 years. Not only was there a ring of gunge inside where the faceplate was in contact with the wall but the back of the socket was covered in in a very fine layer of sticky to the touch mix of fatty/oily dust. I elected to replace the socket. Maybe this kind of contamination is a source of fuel for burning between two switch contacts.

There ARE no hidden switches....

Could be... in my case it was in a utility room - so less atmospheric contamination (although there is no door between that and the kitchen). Also the socket was only six or seven years old, so I would guess it was probably a slightly less than perfect socket from new.

Back in them old days of bakelite switches, Many tended to fail due to contacts heating and kind of warping internal bits making things even worse. In those days a cheap budget socket from Woolworths lasted a very long time compared to the dark brown first generation of 13a sockets. Their other failure mode was the hot contact simply melting the plastic making the contact spring onto the pin. Brian

But Bakelite is thermosetting. Perhaps some thermoplastic that looked like Bakelite?

It's funny how zero can be a plural! Bill

You haven't come across IEEE 754 that has has two zeros, −0 (negative zero) and +0 (positive zero).