Bought some sockets today, put the 2.5mm in, tightened the screw, the cable promptly fell back out as the screw left too much room at either side.
What would a proper electrician do in this circumstance? I folded the cable double but not really happy. Is this a common 'problem'?
Wouldn't mind if i'd got them at the pound shop but they came from an electrical wholesaler.
I thought that was how you should do it. The space is to allow ring main in and ring main out, plus possibly a cable to a single socket spur. I'd be more annoyed if there wasn't anough space to allow this.
Care to name the brand and model number of the sockets?
The regs allow for 3 cables without modification. ie no bending double
ISTR BS1363 pt 2
Selectric Square IIRC.
Plenty of space, my bother is that the terminal screw is too narrow allowing the cable to slip to either side rather than clamping it.
I know them.
Square wire holder with a round screw.
Put the cables in diagonally into the screw holder and the screw might grab them.
Can't see anything wrong with folding double if only putting a single wire in.
There is probably a crimp terminal you can put on if needed.
Maybe
Or could you file the bottom of the screw flat.
Poor design. Better quality ones have a screw which can almost fill the terminal hole if screwed all the way in, no space for a cable to escape.
Agreed.
I used loads yesterday. But that was on flex to relays and PSUs - probably the most unpleasant job I have ever done. Some dick wants mag locks on some small roller shutter doors to secure them in the open and closed positions.
No specs, no design just get on with it and it seems no one has tried it before. The working hours are 10am to 11am and 12.15 pm to 3pm but you can only work on the outside of the shutters between 12.30pm and 2pm. All shutters must be left in a working state when you are not working on them. I also need to mention that it takes 5 minutes to get from the inside to the outside of the shutters and even when open there is only a small access panel to pass tools through (you can just get an impact driver through it). The walls are steel lined ply with insulation in the cavity.
No access to the internet to learn how to set the limit switches on the roller shutters (worked that one out on site by trial and error) and no manual for the shutter door controls (had to "read" the PCB to see how that worked).
Need an extra tool or part? A trip to the van is a 20 minute round trip.
And it works flawlessly. Only another 7 to do.
Has to be a prison - cell doors perhaps - or maybe food serving slots?
Charles F
Medical servery in a prison.
Everyone should visit one.
I've seen this as well, but always I find that several months after installation you need to retighten the screws due to it all relaxing. If you strip enough and fold it nicely it then grips quite well. I'm surprised technology has not improved on a screw by now, maybe to a screw pushing a spring plate system as you can find in some terminal blocks. Those seem firm as there is no real space for the wire to slip round the side, but then holes are often not round but rectangular. Brian
There seem to me to be very few well designed screw down terminals in most 'standard' electrical items.
Many in Consumer Units are far too easy to get the wire/bus the wrong side of the clamping plate. The ones in plugs and sockets often suffer from the problem the OP describes. Many in junction boxes have silly round ended grub screws that seem to be the most un-useful shape they could possibly be.
Brian Gaff brought next idea :
It has, some accessory manufacturers use exactly what you describe. A square socket/hole for the cable, with a metal plate tightened down by a screw. Whether they are better or not, is debatable - they make it more complex/ more points of potential failure.
What I particularly hate, is the type which uses a soft metal plate, which deforms. Undoing the screw and pulling the wire out, leaves the plate still deformed - so it is difficult to reinsert the wire.
And you cannot get the bus bar the wrong side of MK and Hager MCBs.
13 amp sockets are designed for up to three 2.5mm cables. Having just one, pretty well the rarest siituation. Doubling the cable is the normal way.
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