RoSPA NI : Electricity and You
Flexes and Cables
Flexible Cords - Choosing the Flex
Flex or Cable?
There are two types of electric wiring: flexible cords (flexes) (1) connect electrical appliances to the mains via plugs; cables (2) are used for permanent wiring around the house.
There are many sizes and types of flexible cord. They are all made up of two or three separately insulated cores. In each of these cores the conductor is made up of many thin strands of copper which give the cord its flexibility. In three-core flex the cores are colour coded; brown for live, blue for neutral, green and yellow striped for earth (3). Two-core flex has only the live and neutral conductors, coloured brown and blue. The outer sheath of a flex can be PVC or rubber or rubber/textile braided. Two-core flex can have a round or flat sheath.
Note: If you are replacing a cord on an old appliance you may find that the colours are different from those now available in shops. The old green is now striped green and yellow to be connected to earth or E, the old red is now brown to be connected to live or L, and the old black is now blue to be connected to neutral or N.
Choosing the Flex
Size of conductor
To select the correct size of flex you must know the wattage of the appliance. This can be obtained from the rating plate on the appliance (4). Some appliances such as freezers, refrigerators and vacuum cleaners need a size larger than the wattage indicates. Select the size from Table 1 below.
Table 1
| Wattage up to | (Amps) | Conductor size | Typical appliances |
|---|---|---|---|
| 720 | (3A) | 0.5 mm2 | Table lamps, food mixers, certain hair dryers. Note, length must not exceed 2 m |
| 1440 | (6A) | 0.75 mm2 | Refrigerators, vacuum cleaners, electric drills, irons, high power hair dryers, televisions |
| 2400 | (10A) | 1.0 mm2 | New kettles, 2 kW fan heaters |
| 3240 | (13.5A) | 1.25 mm2 | 3 kW fires, older kettles |
| 3840 | (16A) | 1.5 mm2 | Storage heaters, immersion heaters |
Number of cores
Three-core flex is used on appliances needing an earth, (usually metal cased appliances). Two-core flex is used for double insulated appliances. Look for the double insulated symbol (5).
Type of insulation
There are several types of flexible cord. The more common ones are listed in Table 2.
Table 2
| Type of flex | Typical appliances |
|---|---|
| Parallel twin PVC | Clocks |
| Light duty PVC | Fridges, televisions, sewing machines, food mixers, domestic hair dryers, table lamps, plate warmers. All appliances not too hot to handle. |
| Ordinary PVC | Washing machines, tumble dryers, vacuum cleaners, lawnmowers, toasters. |
| Rubber with oil resistant sheath | Frypans – hot appliances |
| Rubber textile braid or ordinary duty PVC | Room heaters |
| Rubber/textile braided | Irons |
| 85°C rubber high temperature cords | Immersion heaters, storage heaters |
| Light duty 85°C PVC cords | Pendant light fittings |
When you have decided on size, number of cores and type, then you can select the correct flexible cord for your particular appliance.
Table 3 below is a ready reference guide showing which flexible cords can be used for certain typical appliances.
Table 3
| Appliance | Typical wattage | Flex size mm2 | Number of cores | Flex type |
|---|---|---|---|---|
| Iron | 1200 | 0.75 | 3 | Rubber/textile braided (unkinkable |
| Toaster | 1400 | 0.75 | 3 | Ordinary duty PVC |
| Room heater | 1400 2000 3000 |
0.75 1.0 1.25 |
3 3 3 |
Rubber insulated textile braided or ordinary duty PVC |
| Vacuum cleaner | 400 to 1000 | 0.75 | 2 or 3† | Ordinary duty PVC |
| Lawnmower | 700 to 1400 | 0.75 | 2 or 3† | Ordinary duty PVC |
| Kettle | 1200 1500 2400 3000 |
0.75 1.0 1.0 1.25 |
3 3 3 3 |
Ordinary duty PVC. Recommended buy complete with connector |
| Extension lead | 1000 3000* |
1.0 1.5 |
3 3 |
Ordinary duty PVC *when fully uncoiled |
| Immersion heater Storage heater |
3000 | 1.5 | 3 | 85°C rubber insulated high temperature cord |
| Clock | 1 | 0.5 | Usually 2 | Parallel twin PVC, length not to exceed 2 m |
| Slow cooker | 1500 | 1.0 | 2 or 3… | Ordinary duty PVC |
| Deep fryer | 1500 | 1.0 | 2 or 3… | Rubber with oil resistant sheath |
| Hair dryer Refrigerator Food mixer |
1400 | 0.75 | 2 or 3… | Light duty PVC |
| Table lamp | 40 to 100 | 0.5 | 2 or 3… | Light duty PVC. Length not to exceed 2 m, if it does exceed 2 m, use 0.75 mm2 flex |
† Where 2 or 3 cores are shown above replace as the maker intended.
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