Would 7 pin Din connectors suit? Cheap as chips on Ebay

Maybe in an emergency; I wouldn't. Quite apart from the 240VAC issue I hate the things. And they get worse as more pins are added. Not intended for repeat insertions either, yuk.

This aviation type might better, rated for 240Vac @ 5A.

7 pin plugs or 8 or 9? Don't forget neutral and earth.

Could the requirement be tweaked? I don't care much for multicore mains cabling with plugs and sockets if it can be avoided. Presumably a controller is operating remote equipment? If so, I'd prefer to send low voltage control signals to switch the mains remotely via relays. Isolating mains power from the control system could be safer.

Dave

The one you specify would suit. I would like to see sleeving on the soldered connections though.

It is amazing the things you do in your youth though. Three of us used to run Disco's as teenagers starting off in the local Scout hut. Early light show was driven by a motor driving a set of cams operating microswitches leading off to various 3 way spot banks etc. Well we wanted a 3 colour spot bank down the other end of the hut and had no multicore let alone connectors. Solution. Three lives sent down an ordinary mains extension cable one channel on each pin. Pick up the Neutral and Earth from a handy mains socket on the far end wall and Bobs yer uncle, Charlies yer aunt and Fanny's in the air force as they say.

Make you cringe now doesn't it.

regards Martin

I like the Bulgin 8 pin style for this sort of thing RS 487-378 and 487-384. Not uber cheap tho' at around £15 the pair from RS and quite large.

Clive

When Weller first introduced their temperature controlled soldering irons the lead from the base to the iron, which needed 3 wires carrying 24V AC and ground, were attached at the base to shrouded terminals with little strain relief. So they upgraded the design and used a miniature Bulgin type connector – this was about a half-scale version of the old 1" diameter bulgin connectors that were often used for the mains lead on various instruments, hifi etc before IEC connectors came along. However the small Bulgin was actually designed to carry mains and certain equipment actually used it for that so there were mains leads around with 13A plugs on one end and the miniature Bulgin plug on the other – and it was possible to plug this in to the 24V output on the soldering iron base!

Well one bright spark technician in the Post Office Research dept where I worked thought they would demonstrate to the safety people what could happen – it was most spectacular as the transformer tried to deliver 2400V to the mains plug! That design did not last very long! A good demonstration of why careful connector selection is very important.

At Uni in the seventies all of the halls of residence had hall parties and I was one of the student techs who provided lights, sound and sometimes projection.

None of the extension leads we used (all 13A plugs and sockets) had fuses fitted these were only in the adaptors from Wylix plugs which were the standard in the Halls. So if a fuse blew you traced the lead(s) back to the Wylix socket and you knew that was where the fuse had blown. Saved checking each lead in a line of several.

Technically this became possible after a previous student had discovered that one of the materials testing machines in the materials lab used samples 3/16" diameter and the right length to fit in a 13A plugtop!

Even us students were never able to blow 3/16" dia mild steel fuses. At least not in my time…………

Edited By Nick Clarke 3 on 26/03/2020 18:24:46

Another type I like is the ITT Canon Trident Ringlock and QM series connector pairs. A little smaller than the Bulgin ones with crimp type removable contacts so much easier to assemble.

But you need to buy contact sets separately, ideally should get the pukka crimp tool and contact extractor too. All gets very spendy for one plug and socket. I had a bunch of 12 and more way sets to assemble so I got the tools and still have a stash of contacts. If nothing else appeals I could make you up a lead set with, I think, size 16 contacts, its years since I looked at what I have.

Clive

The C091 series are NOT suitable for mains, certainly not UK 240V.
They do have voltage rating of 250V but this is not for direct connection to AC mains supply. Even in an low energy system, isolated from ground they would be marginal.
Assuming you are in the UK, amongst other requirements, any connector carrying mains (other than for double insulated equipment or inside equipment where a tool is required for access) must have an proctive earth contact that makes before the power contacts and breaks after.
Note that neither the 1" or minature Bulgin round connectors are approved for mains use when accesible.

Harting HAN series with earthing contact e.g. 6+E (assuming 1 of your 7 is earth) is about the best choice for multipole mains.

What exactly are you trying to do?

Robert G8RPI.

Have you told Boeing? This may assist their investigation!

Or any other specification, which is why I described them as 'aviation type'!

Mike Poole asked if they 'Are they a cheap copy of a quality connector or are they just a cheap and nastyish component?' I think they're just ordinary. The advantage is the plug can be screwed on to the socket which is handy when there's vibration to worry about.

Mil-spec connectors are usually well-made for a particular purpose, which makes them expensive. If your requirement isn't the same then expect to pay big money for qualities that may well be irrelevant. I remember being surprised that indicator bulbs for Navy helicopters were thirty times more expensive than the ordinary variety, which looked exactly the same. In fact the only difference was the Def-Spec demanding the bulbs to be soak tested for 30 hours and then specially packaged with a NATO stock number. Reason was, if someone was changing a difficult to get at console bulb on a jungle air-strip, they didn't want to find the package contained the wrong bulb, or that it would fail on first test. But for ordinary use, only a BF would pay for the extra reassurance. Other examples, connectors really are first class, strongly made of the best materials and heavily silver-plated. But again, rarely worth the extra money unless reliability really is mission critical.

I own a couple of transceivers, one commercial, the other military (a Clansman PRC230)

The Clansman is a truly solid bit of kit, almost bullet-proof inside a cast Aluminium case. It's simple to operate, water-proof (for minimum 2 hours at 1 metre deep), and can transmit USB/AM voice or morse code anywhere in the range 2-30Mhz, most of which is illegal. Plug in battery pack, came with a charger for use with 24V vehicles, a hand-generator, noise-cancelling headphones for use in a tank, and a device allowing the operator to work the radio from 1.5km away. (This is because people shoot at coordinates revealed by direction finding.) The frequency can be set by feel and the whole radio can be operated in pitch darkness. The morse key is near silent to prevent key clicks giving it's position away. Lastly the radio is neutral buoyancy so that it won't drown the operator if he falls into a river. (An earlier backpack radio drowned several chaps by forcing them face down into the water because it floated.) Naturally, the radio will work in the Arctic, Jungle or Sahara and on any mountain top, or in an unpressurised aircraft. It has wonderful water-proof connectors!

Although the PRC320 oozes quality and cost several thousand pounds new, it has multiple disadvantages for ordinary use. Weighing at 11kg plus it needs a fit young man to carry it any distance. The hand-generator demands plenty of stamina and upper arm strength. The noise-cancelling headphones and remote operating features are useless off the battlefield. Being able to operate the radio in the dark makes the controls slow to operate. And, because the radio is designed to work over fixed channels, it isn't frequency agile. The AM voice mode is mostly obsolete, and – for ham radio use – LSB is needed as well as USB.

In comparison, the commercial equivalent has the same receive performance, plus LSB and data modes. It's delicate and far from waterproof. But it's 3 times more powerful, frequency agile within legal limits, and physically much smaller and lighter – it weighs under 2kg.

Lesson learned, don't spend on 'quality' without confirming it's essential! It's too easy to waste good money on unnecessary features. Match the specification to a carefully considered requirement instead. Under and over-specifying are both egregious sins!

Dave