One of the real dangers involving electricity is the joining up of flex, which can be a fire hazard. If you really have to do this job, always use a proper connector and check you have wired it up in the correct way.
Whenever possible avoid joining flex. If you have to, always use a proper connector and never try to join two pieces of flex by twisting the bare wires together and covering them with insulating tape. No matter how careful you are there is always a danger the join may work loose or come apart because it is suddenly stretched. If a join does work loose it can create sparks that may in turn lead to a fire. Among the other hazards, the earth safety lead may become detached in a three core flex join or the essential separation between the live and neutral wires break down, causing a short circuit.
Flex connectors are useful for portable appliances like irons and hairdryers, if you want to use them some distance from a socket. But never use more than one connector on a length of flex and don’t trail it under carpets, up the stairs or across a passageway. Apart from the electrical dangers, there is always the risk someone might trip over it. When you require temporary lighting for a Christmas tree, for example, the flex and connector should be tucked against a skirting board and secured with adhesive tape, never by staples.
Before you decide you need to make a connection, consider whether it is easier, possibly cheaper, and certainly safer to buy a longer length of flex and fit it permanently to the lamp or appliance. Alternatively it could be preferable, though more expensive, to have a new power socket fitted, especially if it is for a semi-permanent appliance like a fridge, television or room heater.
Proper flex connectors do not only keep the cores separate but the screw terminals keep them securely fixed. Always use the same kind of flexes when making a join; although they need not be the same exterior colour, the amps and number of cores must match – three core must be matched with three core and two core with two core.
Only trim sufficient outer insulating sheath and inner insulation to leave the minimum bare wire to enter the connector terminals. Make sure there are no bare strands of wire exposed by twisting together the strands in each core before connecting. Always connect the brown core with brown, the blue with blue and the green/yellow earth with earth and check the plug at the end of the extension flex is correctly wired and fused.
Types of connectors
Three kinds of connectors are available for use in the home. But check which one is most suitable for the type of appliance involved and where it is to be used.
Connector strips Sometimes called block connectors, they are made of plastic and pairs of screws hold the flex ends. The plastic section can be cut to suit single, two or three core flex, but since the
screw heads are not insulated they are only suitable where they can be protected and insulated, such as inside a table lamp or appliance, or in a plastic box with a screw-down cover.
Insulated flex connectors These consist of a screw-down plastic cover with screw terminals inside. You buy them to suit the flex and the appliance: 5amp for small lamps and 1 3amp for most other uses. They are generally designed to accommodate the live, neutral and earth of three core flex but can be used with two core flex.
Insulated detachable flex connectors Made of rubber or a tough plastic, these are like a self-contained plug and socket and strong enough for outdoor use. They are available in 5 and I 3amp sizes. You must always fix the ‘male’ or plug part of the connector on the flex leading to the appliance and the ‘female’ or socket half should be connected with the flex end that will be joined to the plug connecting with the mains. If you join them the other way round and they become detached, the part with the pins would be live to the touch – and therefore very dangerous.