This standard specifies requirements for 13 A fused fixed connection units for household, commercial and light industrial purposes, with particular reference to safety in normal use. The connection units are suitable for the connection of appliances, in a.c. circuits only, operating at voltages not exceeding 250 V r.m.s. at 50 Hz.\nRequirements are specified for connection units incorporating a fuse-link complying with SS 167.\nRequirements are specified for 13 A connection units, with or without associated controlling switches, for flush mounting in suitable enclosures, e.g. boxes complying with BS 4662, or for surface or panel mounting. Connection units are intended for use with cables complying with BS 6004 having copper conductors. Connection units with cord outlets are additionally intended for use with flexible cords, complying with SS 358-5 or IEC 60227-5 on the load (output) side. Connection units containing devices other than fuse-links, switches and indicator lamps are outside the scope of this standard.\nA connection unit does not emit intolerable electromagnetic interference since significant electromagnetic disturbances are only generated during insertion and withdrawal which are not continuous.\nA connection unit is mechanical by nature of construction. The product is therefore immune from electromagnetic interference.\nFused connection units shall be suitable for use under the following conditions:\nAn ambient temperature having a peak value not exceeding + 40℃, the average value over 24 h not exceeding + 35℃;\nA situation not subject to exposure to direct radiation from the sun or other source of heat likely to raise temperatures above the limits specified in (a);\nAn altitude not exceeding 1000 m above sea level;\nAn atmosphere not subject to abnormal pollution by smoke, chemical fumes, rain, spray, prolonged periods of high humidity or other abnormal conditions. This is equivalent to pollution degree 2, see Annex E, and overvoltage category III, see Annex D.