How to Connect a Mains Plug

by Frank Weithöner

Estimate the cable length inside the plug. Take your side cutter and cut carefully a groove around the cable sheath.

Grip the cable sheath... ...and pull it off.

Cut the single cables to length. Cut carefully a groove around the single cables.

This step is not needed when your cutter has a dismantling function. Grip the cable insulation and pull it off.

Twist the core wire... ...and tin it. Therefore heat up the cable and add the solder to the cable.

Hint: Tinning of cable ends should only be done if no cable end ferrules and a crimping tool are available.

Screw the cables to the terminals. Make sure that the cables do not get squeezed when the cover is fitted. Mount the strain relief. The strain relief should firmly enclose the cable sheath.

Note: At a perfect installation the green/yellow PE cable is longer than line and neutral. This is because if someone pulls the cable and the strain relief fails the PE cable will disconnect at last.


When the core wire is very thin, fold the end over and double the wire diameter before tinning. With thin two-core cables the strain relief might not work. Turn around the cable clamp then.

Hint: In principle the cable colours of a mains supply cable can be ignored (from the wall socket to the unit - NOT within the building installation). No equipment will function differently when the cables are interchanged. In fact many plug systems in the world are not reverse polarity protected and the plug can be inserted into the wall socket in either way.

Links and sources
     Wikipedia: AC power plugs and sockets