Golborne Vintage Radio

A friend phoned me the other day saying their dishwasher was dead and could I help. I was a bit reluctant but asked the relevant questions and got them to take a shot of the connections when it was pulled out. The flex went via a "tape bomb" to a flex outlet plate. it had its own MCB in the consumer unit. I got them to check that all was secure inside the tape bomb.

While it's not a true domestic emergency I decided on balance that I could go and have a look. Especially as the presence of a tape bomb sugegsted there might be a genuine hazard. I had to repeat measurements several times to convince myself about what I'd found. Both live and neutral were open circuit between the CU and the outlet. Earth was OK but that could have been a fortuitous path. The presumed cable route was over the ceiling and down so my though was that the upstairs neighbour had done something silly unde their floorboards. This was denied. If it had been just one core then I might have believed mice though 2.5mm T+E would be pretty tough for them. Neither the RCD nor MCB (16A) had tripped.

I am truly puzzled byt this one. I wonder if I will ever find the true cause of the fault.

I did resolve the tape bomb. They'd had a new (to them) dishwasher installed. The installer should have fitted a socket instead of the flex outlet plate but wired the new machine into the flex outlet. Subsequently the machine had been taken away for repair. The repairer had obviously just cut the flex and used a tape bomb to rejoin it.

The immediate fix was putting a plug on the flex and using an extension to connect it to another socket. I also disconencted the circuit at the CU. The long term fix will be a new socket on the kitchen ring whose cables pass close by and are readily accessible. The kitchen ring doesn't have any other heavy loads so it will be fine.

That's worrying as to where and how the cable is open circuit.
The tape bomb is very bad practice and whoever did it needs some training.

This is a circuit that's been working for decades but failed suddenly. I've looked at other bits of electrics at their maisonette before and the general installation standard isn't great. Work has been done by the economical types who keep the wires in a back box as short as possible. The ones for the flex outlet plate I removed were in that class. Fitting a socket would probably have meant extending them with choc bloc. I don't like it but it's OK if it's inside the back box. The kitchen ring wiring behind the dishwasher is nicely draped over central heating pipes. The CH boiler is plugged into a socket outlet via another tape bomb. If and when I do a permanent fix for the dishwasher I'll put in a proper connection for the boiler as it's nearby and I'll be working on the kitchen ring anyway.

The plumbers weren't much better. The boiler has plastic pipework brough right up to it which contradicts manufacturer's instructions. The pipework in the corner under the boiler (all visible when the dishwasher was out) could have been done by a spider. Some years ago the CH system wouldn't hold pressure. One of the rads had a tiny pinhole leak at the back near the top. Not a place you'd expect to leak. For once a fault that couldn't readily be blamed on the installer.

What does "tape bomb" mean? Twisted together then wrapped in insulating tape, perhaps? Google didn't help, unless you're talking about incendiary devices, which you're clearly not (but I learnt something new today - just hope I don't get a knock on the door!). Obviously Trevor is familiar with the term, but if I'm not, I'm sure I won't be the only one

These days I'd use Wagos or equivalent to extend the wiring in the back box. I bought a cheap selection box years ago so I could figure out which ones I liked best before buying in larger packs.

We have a similar scenario here with our cooker outlet. Luckily it's not needed as our cooker is gas, but I'm presuming the back-box for the absent cooker control unit is behind the plasterboard. Eventually we'll gut the kitchen - including the badly done dry-lining - and I'm sure it'll all become clear at that point.

+1 for Wago connectors. I use the 221 series, mainly the 2-, 3- and 5-way blocks.

Really easy to use, reliable and very quick.

One tiny point: under the current regs, they don't count as a protected connector as it's theoretically possible to touch something live if someone gets their hand near one.

I therefore use Wago Gelboxes in those cases where IP-rated protection is required, and standard Wago boxes in normal domestic environments.

Tape bombs come in 2 flavours. Regular, with twisted wires, and chocolate, with choc block. The ones at my friend's place were the deluxe chocolate variety.

I've used quite a few Wago connectors and boxes. Excellent kit. Didn't know there were IP rated ones. Inside a metal back box obviously Wagos are fine. But so is choc block. Wagos are quicker and easier.

I've used Wagoboxes, but hadn't come across the Gelboxes before. From what I can see, they appear to be a new product - perhaps less than a year old? I can certainly think of plenty of applications for them.

Putting a fused 13A plug and socket in an in accessible place behind a dishwasher is bad practice as if the fuse fails it is not accessible.

The correct way is an outlet plate with a fused switched spur in an accessible place labelled "Dishwasher"

Your fail could be a very tight bend in the PVC cable causing the wire to migrate with time until it shorts, odd though that the earth conductor may be still continuous.

Further to all the Wago stuff, Wiska do a great range of IP-rated boxes and connectors...

I've recently done a load of outdoor work with SWA (building a sauna in the garden, plus new power to the greenhouses). I used the Wiska range... these for general damp area like cellars and external floodlights: https://www.tlc-direct.co.uk/Products/WK116B.html

...and these for splicing SWA: https://www.tlc-direct.co.uk/Manufacture...index.html

Like Wago, WIska are a company with a great range - the two work very well together. The two companies recognised that professional electricians were pairing the two up regularly, so they even do promotions together: https://www.wiska.com/downloads/WISKA-WA...Series.pdf

TLC have a good selection of both companies' products.

I'm aware that it's not good practice to put a fuse in an inaccessible position. In an existing kitchen compromise may be needed. The chances of a 13A fuse blowing in the absence of a fault is very small. Can't remember the last time it happened to me. In fact it's relatively accessible as the DW slides out easily.

There was never a short in the cable. Neither RCD nor MCB tripped before or after the DW stopped working.