Mains connectors. Plugs v sockets, gender etc.

[frankmcvey]

Split from this thread:-

https://www.vintage-radio.net/forum/...d.php?t=139887

As regards the plug/socket bit, the Tornado ejection seat had a similar arrangement for connecting to the aircraft. They got round the terminology by calling it a "plocket"; I never did find out if the mating half was called a "slug"!

Cheers,

Frank

[Herald1360]

ISTR calling them sugs and plockets. The terms male and female plug and male and female receptacle cover the four basic options for connectors. Add in cable or panel mounting and it gets even more messy!

[ColinTheAmpMan1]

Whatever you call these mains connectors, the concept (I think) is fairly obvious. If there is a metal part that can be touched, then it mustn't be connected to the mains supply when the connectors are separated - otherwise someone could get hurt.
Colin.

[Nuvistor]

The concept is obvious but didn’t stop some wiring up extension leads with a plug at both ends and the socket on the device.

[julie_m]

The in-line flex connectors that you can still buy are clearly labelled "CONNECT TO MAINS" on the socket half and "CONNECT TO APPLIANCE" on the plug half, presumably as an anti-numpty measure.

Plug-to-plug leads are sometimes used with generators, despite recommendations against the practice.

[dave walsh]

I'm sure you are right Frank-you can't legislate for "daftness" though.
All the various Bulgin types and inversions must have seemed like a good idea at the time but they can be bit counter-intuitive with regard to the general presumption that a plug usually goes into a socket [and not the other way round].

I can't see a safety problem with this kit as the live "socket" mains feed will shroud the "plug" pins when inserted and the pins won't be live otherwise-was that the thinking?
The main difficulty might be in finding the right plug [that is really a socket] at the right price-Bulgin bits seem very expensive these days. Unless absolute authenticity was required I'd be inclined to to just hard wire a mains lead in place, leaving the original socket/plug entirely disconnected and safe of course.

Dave W

[Herald1360]

Originally Posted by julie_m

Plug-to-plug leads are sometimes used with generators, despite recommendations against the practice.

Is there any source of mains connectors rated at 16A or so with shrouded pins like "safety" type 4mm banana plugs that could be used for this? It's such a convenient way to connect a domestic backup generator AFTER you turn off the incoming supply switch........

[julie_m]

I don't think so; and even if there was, it probably would only get misused, because you touching the pins is not the only or even the worst hazard, even although it be the most obvious. Besides shorting two phases or a phase and neutral (been there, done that, got the scars from the flying molten metal), there's also a risk of backfeeding into the grid -- or any poor unfortunate s*d working on it.

The "proper" way to do it is to have a suitably-rated changeover switch (or two contactors, both electrically and mechanically interlocked to prevent both closing at once) allowing the consumer unit to be supplied from either the meter or a BS4343 plug (which then need only be rated for as much current as the generator can supply, not necessarily a full load).

By the way, if powering a gas appliance with electronic ignition (such as a boiler, or a fully-automatic oven) from a generator or inverter, there needs to be a DC leakage path from Neutral to Earth for the flame sense, or else it will just go into "ignition fail" lockout.

[dglcomp]

the only connector I can think of that would that is protected both sides (both AC outlet and AC inlet) would be the powercon connector as whilst you can still stick something in a powercon connector and get a shock touching it won't.
there are 3 types, 16A, 20A, 32A the 16A being the only one with breaking capacity with the 16/32A only to be disconnected with the supply off/removed.

But as has been said doing it properly with a changeover switch is the only properly safe way of doing it.

[Craig Sawyers]

I'd agree with the Neutrik Powercon series. They are locking, and only make contact when you rotate them to engage the lock.

The powerCON TRUE1 are the 16A ones that have breaking capacity. The chassis connectors are available in a single unit with both inlet and outlet http://www.neutrik.co.uk/en-uk/power...nectors/nac3px

[Refugee]

There have been a number of attempts at making plugs and sockets with pins that are sleeved both ways over the years.
I have only got a 2 amp plug for this one to boot.

[kalee20]

And of course there are types which are hermaphrodite, such as Anderson connectors.

[Herald1360]

But you can still touch live bits in Andersons- at any rate the bigger ones like the 350A jobbies.

[julie_m]

Even if a plug-to-plug lead were fitted with shrouded pins so that it is impossible for the person holding the connector to touch a live part, this would not prevent backfeeding -- which is arguably a worse situation, since it might expose persons unknown to a highly counter-intuitive shock hazard.

[G6Tanuki]

Originally Posted by julie_m

Even if a plug-to-plug lead were fitted with shrouded pins so that it is impossible for the person holding the connector to touch a live part, this would not prevent backfeeding -- which is arguably a worse situation, since it might expose persons unknown to a highly counter-intuitive shock hazard.

That is indeed the big problem with generator setups: you may kludge together a "2 plugs on a piece of wire" way to connect your generator to your house-wiring when the power's out but if it happens to provide a backfeed to the distribution network, and some unfortunate powerline technician happens to be up the pole trying to reconnect you.... well, I'd not want to be the one filling in the paperwork.

Even if you get away with it and don't kill a line technician, 'backfeed' to the grid could get interesting for your little generator when utility-power's restored and it suddenly finds itself out-of-phase and fighting the grid! I know which one's going to lose.

Proper generator-switching systems employ positive interlocks to prevent this sort of nastiness.

[G6Tanuki]

Originally Posted by Craig Sawyers

I'd agree with the Neutrik Powercon series. They are locking, and only make contact when you rotate them to engage the lock.

The powerCON TRUE1 are the 16A ones that have breaking capacity. The chassis connectors are available in a single unit with both inlet and outlet http://www.neutrik.co.uk/en-uk/power...nectors/nac3px

I rather like the VEAM/ITT_Cannon "Powerlock" connectors for serious stuff: we used these as the standard way to couple-up trailer mounted generators at some of the data-centres I used to be associated with.

There's something rather fun about seeing an entire aisle of 42U racks dedicated *solely* to AC power distribution! Specially when each rack has its own /24 IP-range and lets you monitor the current-draw and switch each of the 64A 3-phase outlets from your laptop.