Fuse Ratings & Appliance Flexes

Your Safety, Our Concern

    Fuse Ratings.

      For the convenience of users, appliance manufacturers have standardised on two plug fuse ratings - 3 Amps & 13 Amps and appropriate flex sizes, fuses as follows:

      3 Amps     for appliances rated up to 700 Watts.

      13 Amps  for appliances rated over 700 Watts.

      A variety of fuse ratings (1 Amp, 2 Amps, 3 Amps, 5 Amps, 7 Amps, 10 Amps & 13 Amps common ratings in bold)are still available.

      The fuse in the plug is not fitted to protect the appliance although in practice it often does this. Appliances are generally designed to European Standards for use throughout Europe. In most countries the plug is un-fused.  If an appliance needs a fuse to comply with the standard it must be fitted within the appliance. The fuse in the plug protects against faults in the flex and can allow the use of a reduced Cross-sectional area flexible cable.  This is advantageous for such appliances as electric blankets, soldering irons and Christmas tree lights, where the flexibility of a small flexible cable is desirable.

      With some loads it is normal to use a slightly higher rated fuse than the normal operating current.  For example on 500 Watt haogen floodlights it is normal to use a 5 Amp fuse even though 3 Amps would carry the normal operating current. This is because halogen lights draw a significant surge of current at switch on as their cold resistance is far lower than their resitance at operating temperature.

    Replacement of Appliance Flexes.

      For flexes to be protected by the fuse in a BS 1363 plug there is no limit to their length, providing their cross-sectional area are below the following:

        • 3 Amps     0.5mm2
        • 13 Amps  1,25mm2

      Other considerations such as voltage drop may limit flex lengths.  Smaller cross-sectional areas than those given are acceptable if flex lengths are restricted.  However, for replacement purposes the above simplified guidance is appropriate.

      The maximum lengths recommended for extension leads are not applicable to appliance flexes or cord sets.

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