Sprung wiring connectors on sockets

maintenance-free locations, and it got me wondering why the wire connection s on the backs of sockets etc aren't using this sort of technology? Screw t erminals seem rather poor in comparison with a number of issues that could be improved upon with spring connectors. What am I missing as to why this h asn't happened?

Probably because each terminal on a socket is designed to accept at least t hree 2.5mm2 wires whereas each terminal on a Wago accepts a single cable. I n view of this I think it is matter of space available to provide enough sp ring loaded terminals to achieve the same.

Richard

What makes you think a spring is going to provide a better connection than a screw? It would have to be a *very* powerful spring to get even near the same pressure.

or 2 x 4mm so the connectors would have to cope with a wide range of solid and stranded

Given you can use these spring type connectors in inaccessible places does suggest they are more reliable long term.

One thing about a spring is it can take up movement which will be caused by continual temperature cycling and consequential thermal expansion and contraction.

I have come across screws that need to be tightened on shower connections and their associated ceiling switches. In fact if you use aluminium cable the IET regs says you need to service the screw connections on a regular basis.

Otherwise, I agree it does feel counter-intuitive.

Have you looked inside a wago connector?

Inertia - i.e. its always been done that way, and perhaps cost.

(BS1363-2 does have quite extensive chapter and verse on use of screwless terminals - so the standards do support the use of them (at least of 2016 - II have not checked earlier versions)

On a practical level they would need to be the leaver type rather than just "push in" to allow for easy dismounting of wires when doing inspection and test.

I have and wondered about the limited contact area between the spring and cable.

It was the prevalence of such connectors being used in junction boxes, ligh t fittings etc and the fact that they can be used in maintenance-free situa tions unlike screw terminals that gave me the though and properties such as foolproof method of connection (no torque issues to consider) and low (zer o?) risk of the connection coming loose that appealed.

In case you are not familiar, this is the sort of thing I was thinking of:

Regarding pressure, either the spring does in fact apply the similar pressu re as a screw or (more likely) it provides sufficient pressure for electric al contact and relies on mechanical barbing to prevent pullout.

Whilst anecdotal and subject to sample size bias, but I often hear/read abo ut loose screw terminals but have never hear of Wago failures.

three 2.5mm2 wires whereas each terminal on a Wago accepts a single cable. In view of this I think it is matter of space available to provide enough spring loaded terminals to achieve the same.

Yes, that'd have to be a consideration but there is a lot of space within t he internals of a socket and looking at the size of a Wago 221 - particular ly the innards - they're not exactly bulky.

I see the need for one-cable-per-terminal to actually be an advantage as it 'd avoid the potential issue that arise from compressing multiple cables in a screw terminal e.g. variation of contact pressure if sitting side-by-sid e etc.

Yes, but I guess that's where the inherent properties of a spring loaded terminal makes it a non-issue as they usually do accept a wide range of cable types.

..and judging by the responses received not everyone (i.e. no one!) is convinced as I am. Maybe it's one for Dragon's Den... ;-)

Yes, and I must admit to preferring the lever type anyway - far easier to use even for a wire connector where twisting to remove isn't so much of an issue.

Have you ever encountered sprung connections on the back of speakers? Crap connections. Brian

different animals, I'd send you a picture, but ...

ght fittings etc and the fact that they can be used in maintenance-free sit uations unlike screw terminals that gave me the though and properties such as foolproof method of connection (no torque issues to consider) and low (z ero?) risk of the connection coming loose that appealed.

if only.

sure as a screw

no chance. none.

nd relies on mechanical barbing to prevent pullout.

connections also need to be gastight.

bout loose screw terminals but have never hear of Wago failures.

There are many million screw connectors in use, far fewer spring connectors . Springs are widely used in US sockets and are notorious for high resistan ce failures.

I don't know why no-one uses spot welding.

NT

you don't have a patent on them

easier if the wire's straight and clean. But reliable? not especially.

NT

f maintenance-free locations, and it got me wondering why the wire connecti ons on the backs of sockets etc aren't using this sort of technology? Screw terminals seem rather poor in comparison with a number of issues that coul d be improved upon with spring connectors. What am I missing as to why this hasn't happened?

three 2.5mm2 wires whereas each terminal on a Wago accepts a single cable. In view of this I think it is matter of space available to provide enough spring loaded terminals to achieve the same.

It has always seemed wrong to stuff multiple wires into one terminal.

I know there would be issues, but I have always wanted one terminal per wir e.

Never seen a Proteus MCB? ;-)

Owain

Somewhat off topic but.... They had them on some striplights battens I bought recently, pain in the arse when using flex.