Doubling over copper conductors
- Thread starter Jupiter01
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My opinion is that doubling the end of a single conductor can reduce the risk of the conductor moving into an area where the screw is not able to exert adequate pressure onto the conductor
Is this the case when you are squeezing two cables into the same terminal too?
Best practise is to aim to fill a terminal with the copper, to maximise contact area between wire and terminal.
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On a ring circuit, where you have two 2.5mm cables, do you double over the cables into each terminal? Whilst I understand the principle, I wanted to understand its application in this situation please.
Im sure I bend over a single wire, but dont if there are 2
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I would say it depends on the terminal as to if appropriate. With the spring type/maintenance free I would say no, @Harry Bloomfield has made a good comment, so has @bernardgreen but often there are metal parts within the terminal which means the screw is not in direct contact with the wire, we normally limit it to three cables per terminal so all three are reasonably likely to have even pressure, where cables are not all same size, for example a radial with 2 x 4 mm² plus a spur with 2.5 mm² it may be a good idea to just fold the 2.5 mm² but one needs to use ones own judgement as to what is best with that terminal, ideal is one terminal for one wire, but rare with domestic to be able to do this.
I spend time to carefully bend wires in a double socket around in a loop, and then cropped and bent so they are in line with the terminal when the socket is being pushed back into its backbox.
The loop creates a bit of a soft spring making relocation quite easy
bunging it in randomly can mean a lot of pressure and risk of trapping when screwing socket back
The loop creates a bit of a soft spring making relocation quite easy
bunging it in randomly can mean a lot of pressure and risk of trapping when screwing socket back
Depends on the type of terminal and how well it is designed and manufactured
A cage clamp terminal where the screw presses onto a plate which then presses onto the conductor(s) will in most cases exert pressure on all the conductor(s) in the cage. All the conductors or just a single conductor are trapped in the cage and cannot escape the pressure as the screw squeezes the cage,
A screw down terminal where the screw presses directly onto the conductor may allow conductors to "escape" the pressure from the screw.
If the conductors are the same diameter then in a cage clamp terminal doubling over is not essential
If the conductors are not the same diameter then I would double both to keep the pressure plate level and therefore exerting equal pressure on all the conductors
No need, two not doubled 2.5mm would normally be adequate to fill the terminal.
maybe because the designers have never installed any electrical wiring in the real world.
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