Fitting a mains plug.

[Herald1360]

Originally Posted by Kentode

I've used this for years and it works really well, although I'm going to include a loop in the earth wire from now on as it makes sense.

On a side note, buying good quality wire strippers which don't break or score the conductor strands are worthwhile, l know some on here use their teeth!

Hopefully 7mm is enough for the stripped portions to reach right through the connection blocks. The illustration is somewhat misleading on that account!

[G6Tanuki]

For thin conductors I usually stripped rather more and folded it back so there was a bit more 'meat' for the clamp-screw to bite into.

I've come across some plugs wired where the core wires have been folded-back over the insulation before the screw has been tightened; PVC is much-more-amenable to 'cold flow' issues and so this is much worse than tinning the flex-ends before fitting them to a plug.

Thought-for-the-day: why hasn't someone produced a 13A plug with springy-wiring-connectors - WAGO-connector-style ?? It would make fitting a legacy wired-on plug so much faster and secure.

[Electronpusher0]

Originally Posted by Kentode

On a side note, buying good quality wire strippers which don't break or score the conductor strands are worthwhile, l know some on here use their teeth!

I have a small chip out of one of my front teeth from doing that years ago.

Peter

[Glowing Bits!]

I couldn't help noticing how 10A and 7A fuses have started making a comeback, I purchased a percolator machine recently and it says '7 A fuse fitted' on the plug, masterplug are starting to fit 10A fuses in their extension leads nowadays.
One thing worth mentioning is earth wires on extension sockets, I recently acquired 5 used extensions, one socket had a defective earth, found while using a socket tester, there is no slack whatsoever and the damn thing pulled out!

[ms660]

Older style 13A plug break down plus video:

https://www.flameport.com/electric_m...ss_UK_plug.cs4

Lawrence.

[Lucien Nunes]

I couldn't help noticing how modern fan heaters are rated at 2kW but have a 0.75mm cable fitted, the fuse should be either 5A or 10A but is usually 13A, this is a fire waiting to happen!

Unlikely to make a great difference. The fuse protects against overload and short circuit - two very different scenarios. In reality it is most unusual for a 'fixed load' such as a heater to draw excessive current without self-destructing very quickly, and a 10A fuse wouldn't really stop it overheating if it is faulty. In the obscure scenario that the element got tangled up and partially shorted, it could dissipate 3kW for quite a long time before a 10A fuse operated. The protection against fire in this case is the internal thermal cutout and the backup thermal fuse, which respond to the actual hazard (temperature) rather than the current.

However, in the event of a short-circuit, a 13A fuse will quite adequately protect a 0.75mm² flex, as will a 16A. It's an adiabatic race - the heat dumped instantaneously into the flex is governed by the I²t of the fuse and for all reasonable levels of loop impedance 13A is fine on 0.75.

There is, as mentioned above, a genuine advantage where possible in using the most highly rated plug fuse that is safe, since it results in the lowest heat dissipation in the plug. Many fuse clips and contacts are not up to the standards one would really like to see, and thermal runaway is very common where the fuse heats the clips, which oxidise, increase in resistance, heat the pins, tarnish the socket contacts, which heat up...

Having done literally hundreds of post-mortems on plug and socket burnouts with my electrical safety consultant's hat on, I would earnestly suggest that if the appliance has its own adequate safety measures intact, fusing a heating load down to the lowest rating possible is not always the best policy, expecially if the plug is likely to be left permanently in the socket-outlet as this is a common factor in thermal runaway as the oxidation is never wiped off.

Returning to the original comment, I fully agree that 0.75mm² on a 2kW 230V appliance is cheeky and penny-pinching. Kettles with short duty-cycles, just maybe. Heaters, not clever.

[Richard_FM]

I remember shops like Comet used to have a display bin of plugs for new purchases.

My Dad used to recycle plugs, keeping a few around from disposed of appliances. Some cheap ones which didn't last well even on their first device convinced him to buy a box of Micromark plugs which probably lasted until fitted ones became standard.

[Skywave]

I know the sub-topic of lead length inside the plug has been mentioned above, but I just thought I'd add this . . .

In past employment as a repair technician for PC equipment in a firm that catered for government security organisations and such like (you know those places - but no names, no pack drill!), it was a specific requirement that the wiring had to be of such lengths that if the wiring became pulled out of the plug, it had to be cut so that the L wire came out first, E wire last.
Occasionally, my handiwork would be inspected by the supervisor - just to make sure - because it was known that the customers would always check it anyway.

Al.

[Tim]

Thought-for-the-day: why hasn't someone produced a 13A plug with springy-wiring-connectors - WAGO-connector-style ?? It would make fitting a legacy wired-on plug so much faster and secure.

I think they did, some years ago. As I remember it was marketed as "The electrician free plug", and was supposed to enable the user(fitee?) to fit the plug onto a cable without the use of a screwdriver. I cant remember who made it though, and it seems a bit of a gimmick, as in many cases the wires would be the wrong length on the particular flex you had, or of course may need the outer sheath stripping off.


Those "Legrand" slimline plugs are my favourite too(SAD ALARM!!!!) and I still have a number of them, sheathed and un sheathed, fitted on various things around here. They seemed to be the perfect plug, nice and small, resilient, good quality and aesthetically pleasing(at least to me anyway). .ISTR they were also available in different colours, but you don't see those very often
I have a "BBC" one, a "BRITISH AEROSPACE" one and a "SWEB" one I think. I remember getting a "plain" one and doing a naughty swap for the BBC one( just like a previous poster). I think the British Aerospace one came from my time there on work experience from school.

[Tim]

Ah-ha!

the TL handyplug..

https://worldradiohistory.com/UK/Hob...3-10-S-OCR.pdf

page 6

[Graham G3ZVT]

I am glad I'm in good company with my small collection of BICC/Legrand plugs.

Does any of yours have the extra "feature" of two pimples on the back cover where the slightly longer cord-grip screws were accidently used to screw the back to the body?

[Tim]

Not that I am aware Graham

[Lancs Lad]

No, none of mine have those either!

[Lucien Nunes]

I have at least one with pimples! My dad used to stock these in his appliance shop in the 1970s. He considered the MK plug the best but liked the slimline unbreakable construction of the BICC. His were branded 'Aristocrat' but I don't recall the connection. There must still be a dozen in use around the house. Here's one on my Grundig TK18, likely wired by him before I got it 40 years ago.

[Sparks]

I remember one of our Legrands had the Aristocrat brand.

[Stuart R]

I'm sure I've seen 'Aristocrat' branded fridges.

I've resisted jumping in with this one - it's come from an on-line instructional video on making DIY lighting for the home. Or 'Hack" as they like to say these days.....

We're shown how to mount a G9 bulbholder in a lantern designed for a tea-light candle and told to buy some flex, an in-line switch and 13A Plug. We're told to follow the supplied cardboard instructions carefully and somehow end up with this. In their defence, the plug-top card supplied says nothing about stripping back only the first 6mm of each core, although does show the bare copper section marked as 6mm long in a narrower width than the insulated section.

Maybe a colour photo needs to be printed on the card these days?

SR

[Electronpusher0]

Many years ago I got talking to someone who worked at LEC refrigeration in Bognor (now long gone, the site is a Sainsbury's although there is a pub alongside named after the owner, Charlie Purley).
He told me his job was fitting plugs to cables on the fridges, all hand wired, no moulded plugs then.

Peter

[Radio Wrangler]

At least whoever wound up with that plug in the photo was protected from nasty lead.

David

[Tim]

Here’s the British Aerospace one. Got this in the mid 80’s so none of that sleeved pins nonsense!

[hamid_1]

In a way I'm glad that pre-fitted plugs have now become standard in the UK, having seen quite a few badly-wired ones. I'm surprised it took so long for the UK to introduce them. In some countries like the USA and Canada, moulded plugs have been standard since the 1970s or even earlier, and hand-wired plugs are virtually unknown and very hard to find. I appreciate the UK had two different mains plug standards after the war, the old round-pin ones and the new BS1363 flat-pin type. But it wasn't until 1994 that consumer electrical appliances had to be supplied with a 13A plug. By that time, the old BS546 plugs had been practically obsolete for decades. Legislation could have been introduced earlier, or the manufacturers could have been more proactive in supplying appliances with plugs.

Back in the day, you bought the appliance and the plug separately. The appliance cord had bare wires. A couple of things puzzled me. It's agreed that tinning wires in mains plugs is bad practice - the solder 'creeps' eventually causing a loose connection. So why did manufacturers supply their appliances with bare tinned wires? Also, 13A plugs almost always came supplied with 13A fuses. It was only around the late 1980s that you could buy a new plug with a 3A fuse instead. Both of these points led to consumers fitting the tinned wires straight into a new plug with a 13A fuse, even if the fuse value was inappropriate, creating a potential safety hazard.