Getting three wires into one screw hole

ed110220

I've had to rewire my central heating and hot water timer in order to put the cables into a wall before I get it skimmed (they were surface mounted).

Now I came across a problem that seems common - it's almost impossible to get the three wires back into one hole and screw the little screw down on them. Is there any trick to it or is it just always a very fiddly job? I've had the same problem on lighting circuits etc.

Laz123

It is fiddly, but why not take the plastic coating back further on the three wires, use plyers to wrap two wires round the longest bare wire further back so the one wire protrudes and insert the one copper wire into the hole.

Phil_L_2

Because the wires will unwrap themselves and fall off. Never good if it is mains wiring.

Get some proper connectors, probably terminal strip with a maximum of two cables in each terminal. Do not twist the cables together.

muckybutt

Laz123 wrote: »

It is fiddly, but why not take the plastic coating back further on the three wires, use plyers to wrap two wires round the longest bare wire further back so the one wire protrudes and insert the one copper wire into the hole.

Pliers !

Twisting wires together is very bad practice, twisting together as you have described above is downright dangerous. Insulation should as far as reasonable practicable be only stripped back far enough so as to allow connection and should not go back past the point of connection, leaving bare wire exposed past the connection is as i'm sure you can appreciate dangerous.

If you are struggling to get the wires all in place, then either get a larger terminal block and join the wires there, then link it to the point where they should be connceted with a larger size cable. Alternatively use a proper crimp such as a pin crimp.

diable

Why is it bad practice to twist the wires together?

ed110220

diable wrote: »

Why is it bad practice to twist the wires together?

I'm no expert but I assume it's not so much the twisting as having only one wire screwed in and the others simply twisted round it, in which case the twisted wires could come loose. If you managed to screw down all three wires that had been twisted together I think it would be fine.

Correct me if I'm wrong.

Laz123

muckybutt wrote: »

Pliers !

Twisting wires together is very bad practice, twisting together as you have described above is downright dangerous. Insulation should as far as reasonable practicable be only stripped back far enough so as to allow connection and should not go back past the point of connection, leaving bare wire exposed past the connection is as i'm sure you can appreciate dangerous.

If you are struggling to get the wires all in place, then either get a larger terminal block and join the wires there, then link it to the point where they should be connceted with a larger size cable. Alternatively use a proper crimp such as a pin crimp.

I've done this many, many times over the years and there is nothing dangerous about it at all. The three in one wire is no where close to any other wires. Perhaps I should have put some caveats in place but I assumed common sense would prevail; like turn off the supply first, wrap insulating tape over any exposed copper, etc.

roddydogs

Laz123 wrote: »

It is fiddly, but why not take the plastic coating back further on the three wires, use plyers to wrap two wires round the longest bare wire further back so the one wire protrudes and insert the one copper wire into the hole.

Possibly the most dangerous advice ever posted?

DVardysShadow

Laz123 wrote: »

I've done this many, many times over the years and there is nothing dangerous about it at all. The three in one wire is no where close to any other wires. Perhaps I should have put some caveats in place but I assumed common sense would prevail; like turn off the supply first, wrap insulating tape over any exposed copper, etc.

The above advice is wrong and should not be followed

What is dangerous is that there is no assurance that the twisting won't come loose. And then you will have 2 risks

• High resistance connection which can overheat and potentially lead to a fire
• Connection which comes free with the potential to cause a short circuit

If the cable into the electrical fitting is disturbed, the potential for the connection to come loose is very real. As for 'insulating tape', it is correctly known as 'electrical tape' and is used for binding cables together, it is not designed or intended for use as an insulator.

muckybutt

diable wrote: »

Why is it bad practice to twist the wires together?

You can get arcing around the conductors for starters, often twisted wires snap when they are placed in the connection point, a big cause of faults etc etc

ed110220 wrote: »

I'm no expert but I assume it's not so much the twisting as having only one wire screwed in and the others simply twisted round it, in which case the twisted wires could come loose. If you managed to screw down all three wires that had been twisted together I think it would be fine.

Correct me if I'm wrong.

You have proved you are no expert by posting what you did ! twisting together is as I have explained above very bad practice, twisting as you mentioned before is dangerous. Twisting wires together will still be the same as putting them in singularly !

keystone

Laz123 wrote: »

I've done this many, many times over the years and there is nothing dangerous about it at all.

The fact that you have done this before and got away with it doesn't make it any less unsafe. Please understand that there is a very significant fire and shock hazard associated with your method and I wonder how you would feel if some one came on here saying that their brother/friend/neighbour had done it the way you say and burnt the house down last week as a result.

Perhaps I should have put some caveats in place but I assumed common sense would prevail; like turn off the supply first, wrap insulating tape over any exposed copper, etc.

Your method is anything but common sense. Sorry but its plain barmy.

Cheers