Strange house wiring fault

[Murphyv310]

Hi.
Chocolate block is rarely a good idea on mains especially if the load is high.
The continual heating and cooling can lead to the screws loosening off for no apparent reason. Then the connection begins to go high resistance and could of course start a fire.
I've seen crimps in the past that have been also soldered and heat shrink insulation fitted, they have been OK on dismantling TBH.

[Mark Hennessy]

Any experience of Ideal's version?

https://www.screwfix.com/c/electrical-li...industries

The in-line connectors look handy. Not sure if Wago have one like this (apart from the squeezy-block lighting ones)

https://www.screwfix.com/p/ideal-splicel...f-10/42201

Wago do a range with increased touch protection. Haven't seen these in the flesh yet, but could be useful occasionally:

https://www.wago.com/gb/electrical-inter...insta_ip40

[Mark Hennessy]

I've never liked choc-blocs, especially not the most common type made from extremely soft plastic. Really don't like junction boxes either - glad to see the back of those. Copper creeps under pressure, so you need a spring connection. Crimp can be good if done properly with the right tool, but we've all seen badly done joints. But it's good enough for tens and hundreds of amps in cars, which is a pretty harsh environment for a connector.

I've seen spring connectors replacing choc-blocs in lighting fittings. Wonder when that'll happen to accessories like sockets and light switches, if it hasn't already?

I did work experience with a local firm of electrical contractors when I was 14, and it was a week of hammering out recesses for back boxes on one site, and doing second-fix on another. Hard work for a kid, even a moderately strong and fit one (those were the days!). I really struggled with how tight you had to get the screws done up on sockets, and didn't manage it most of the time (they were double-checked, of course). I still struggle - not with strength, but confidence because the whole process is so medieval. I'll usually go back a few days later to see if there's another quarter-turn to be had.

[ppppenguin]

The traditional round junction boxes are horrible things and always were. Good riddance.

Tightening up screw connections is easy. Do it up until it starts to shear or strip the thread, then back off slightly I always go round again and retighten. If you remember the old fashioned Wylex fuse boxes they had twin screws for each L and N conductor. All modern CUs just have a single screw. I reckon this was the cause of many fires and the reason for the amendment to the wiring regs to enforce metalclad CUs.

I mostly use decent quality chocbloc made from medium hard plastic. I can't see it will be any worse than the screw terminals in sockets, light switches etc.

[Kalee20]

Hi.
Chocolate block is rarely a good idea on mains especially if the load is high.
The continual heating and cooling can lead to the screws  loosening off for no apparent reason. Then the connection begins to go high resistance and could of course start a fire.

Though that would apply to connection between cabling and the outlet socket too, of which millions are in use and have been for decades?

(I don't like choc block connectors, however. Temporary, and accessible, I tolerate them. As part of fixed wiring, never).

[Nick]

Any experience of Ideal's version?

'frayed knot! All the sparks I know, including the SE region senior regs examiner, say use Wago and Wiska...

They're really reasonably priced, especially in bulk, and very nice to use.

Btw, I believe that the requirement for metalclad CUs only applies to habitable spaces, so sheds and so on can use plastic IP rated ones.

However, I used IP rated steel cabinets in the greenhouses as there is a bunch of DIN rail mounted control gear in there as well... (Sprinkler controls, timers, contactors, power meters, Raspberry Pis doing stuff, PoE supply, environmental monitoring etc.)

[ppppenguin]

Btw, I believe that the requirement for metalclad CUs only applies to habitable spaces, so sheds and so on can use plastic IP rated ones.

I'm pretty sure that's correct. I suspect you'd have to search fairly hard for a plastic CU these days.

[boater sam]

I have lost count of the number of 13A fuses that have just died, not destructively blown, on dishwashers and other highly loaded appliances. 
There was or is ( I'm out of touch these days )  one make of dishwasher that was rated at 12.6A but at 220V being continental. These used to rot fuses out regularly.

Some washing machines overload the fuse slightly when the motor starts with the heater on.


I hope you can find the reason, its intriguing, would love to know.

[Nick]

Btw, I believe that the requirement for metalclad CUs only applies to habitable spaces, so sheds and so on can use plastic IP rated ones.

I'm pretty sure that's correct. I suspect you'd have to search fairly hard for a plastic CU these days.

Caravan and garage complete units (CU, RCD plus fully populated MCBs) are normally plastic...

[ppppenguin]

Agreed about garage CUs, but I think you'd struggle to find a larger one. ISTR a few years ago, when the amendment*, came in that suppliers like Screfix were knocking out their residue of plastic CUs at bargain price.

*17th edition, amendment 3, effective 1/1/2016