Before doing any electrical wiring it is important to know how to strip the cable effectively without damaging the insulation on the internal conductors. Here we are using standard domestic cable which comes in several different thickness, depending on what it it being used for. Obviously only cut cable or any wire that is not connected to anything at the other end or you could easily be electrocuted!



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Before working on any electrical circuit you must ensure that it is isolated correctly and cannot accidentally be switched back on. Please read the article on safe isolation procedures before doing any electrical work. If you are not 100% certain what you are doing call a qualified electrician. Building regulations are changing all the time and modifying your home electrics could be against new rules and could invalidate your home insurance, if in doubt check first!


The cable can easily be cut to the correct length with a pair of wire cutters or side cutters, simply open up the cutters, place the wire in the jaws and squeeze the handles and the wire will cut.

twin core and earth cable

Using a sharp knife cut a line about three inches long in the outer insulation, making sure that you do not press on too hard as you do not want to cut the insulation of the single cores inside. Cut in the dead centre as this is where the earth wire is situated. This is a essential part of wiring and should be practiced as much as possible until you can successfully cut the outer insulation, without damaging the cores inside. If the inner insulation is damaged you must cut the wire off and start again.

cut insulation

Now pull the three wires out from the outer insulation, the inner core is the earth wire and never has any insulation on it, this needs putting on before wiring it to any appliance. This picture is of a piece of cable, domestic flex wire has a green and yellow sheathed earth wire running through it but on cable there is never any earthing insulation.

earth sleeve

Green and yellow sleeving needs to be put on the earth.

cut off insulation

Cut the remainder of the outer insulation off with a sharp knife and discard this piece. Be sure not to damage the insulation on the individual wires.

expose wires

The outer insulation has now been successfully cut and the insulation on the individual conductors needs trimming.

cable strippers

This insulation is best cut with a pair of wire strippers like these, on the side of the strippers are the sizes of the holes, this corresponds to the thickness of the wire you are stripping, so if you were stripping 2.5mm wire you would use the 2.5 hole. Open the strippers up and place the wire in the correct hole, you need to remove about 7-8 mm of insulation. Squeeze the handles together whilst holding the wire with your other hand and then pull gently and the insulation will be removed.

stripped insulation

The cable is now ready for wiring into the appropriate switch or socket once the earth sleeving is in place of course!


An alternative way of stripping the cable is to grab hold of the earth wire with a pair of pliers and pull the earth wire through the insulation ( a bit like a cheese wire). This is a good method to use as there is less chance of damaging the insulation of the neutral and live conductors.