Connecting and joining wires

This page covers how to safely and reliably connect, splice or join wires together.

Summary

Often during a repair, wires need to be connected or reconnected. Perhaps a worn out flex is being replaced or a failed thermal fuse. Simply twisting the wires together would hardly ever be a good idea, but there are several other ways of doing it.

Safety

Where the wires carry mains voltage it's essential that the join is properly insulated.

If the join may come under strain then the wires should be clamped in some way to prevent the join from pulling apart. This is essential in the case of mains voltages.

Screw and spring terminals

Probably the oldest method of connecting a wire is with a screw terminal. The screw head may hold the wire directly or preferably under a washer, or the screw may clamp the wire in a hole in a brass terminal.

In the case of stranded wire, always keep the individual strands together after stripping the insulation by firmly twisting them together, or better still, applying a little solder.

In the first case, make sure the bare end of the wire is at least long enough to make a half tun around the screw, and always wrap it round the screw in the same direction as you will be tightening it.

Where the screw clamps the wire in a hole n a brass terminal, it's often helpful to strip sufficient insulation so that you can fold the bare end double, so giving the screw plenty to grip on. Alternatively, apply solder to stranded wire.

Joining mains cables

The only way to safely join two flexible mains leads is with an in-line screw terminal connection box. This has a cable clamp at each end which must be used to clamp the outer insulation, not just the inner wires.

Electricians often use a circular junction box without cable clamps, but this is only acceptable where all the cables entering it are secured along their length with cable clips, often nailed to a joist.

Choc block connector

These come in strips which can be easily cut according to the number of wires you need to connect. They are useful for connecting low voltage wires but offer no form of cable clamp so you should ensure that the cables cannot be strained. They contain a hole between each pair of connectors, which you can use to screw them down to a firm base.

Spring terminal connectors

There are several types of these, and they can be used to make a quick and easy connection without any tools (except for stripping the insulation). They are often used for loudspeaker cables and in model train sets, providing a simple way for connections to be made or removed as often as needed. Applying solder to the bare end of stranded wire is helpful.

Soldering

Also heat shrink solder sleeves

Crimping

Also heat shrink crimp connectors

Insulation displacement connectors=

Telephone connectors

Insulating your connections

• PVC tape
• Heat shrink sleeving
• Earth wire sleeving

External links

• External links (if any) as bullet points.
• If none, delete this section.