Fuses IEC Cylindrical

Give the category, size, rated voltage and rated current, exactly as marked: for example gG 14 × 51 mm 690 V 16 A. The voltage is not fixed by the size. In maker tables it drops at the top ratings. In Eaton’s 14 × 51 gG range, 1 to 25 A is 690 V, 32 and 40 A are 500 V and 50 A is 400 V. In 10 × 38, 0.5 to 25 A is 500 V and 32 A is 400 V.^[3]

Do not swap categories. gG gives full-range protection for cables, motors and networks. aM interrupts currents from about 6.3 times its rating upwards. It gives short-circuit protection only and must be paired with other switchgear, such as an overload relay, for overload protection.^[4][5]

The "8 × 32" size is the 8.5 × 31.5 mm fuse that some makers list as 8 × 31. It is a 400 V size with a breaking capacity of 20 kA, against 80 to 120 kA for the larger sizes. Say whether a striker (for a micro-switch fuse indicator) is needed. Eaton offers strikers in 14 × 51 and 22 × 58 only.^[6][3]

IEC 60269-1 is the general standard for these fuses. It covers enclosed current-limiting fuse links with breaking capacities of at least 6 kA, for AC circuits up to 1,000 V. Fuses are made interchangeable by characteristics and dimensions, so a replacement must have the same characteristics and identical dimensions.^[7][8]

On ships, IEC 60092-202 requires short-circuit protection by circuit-breakers or fuses. It permits fuses for overload protection up to 320 A, recommends breakers above 200 A, and does not accept fuses for overload protection in high-voltage AC systems. Where fuses protect polyphase motors, protection against single-phasing has to be considered.^[9]

For US-flag ships, 46 CFR 111.53-1 requires each fuse to have an interrupting rating sufficient for the short-circuit current where it is fitted, and bans renewable-link cartridge fuses. COSWP says never exceed the rated capacity of wires and fuses and never use makeshift fuses. When a fuse is pulled to isolate equipment, the person working on it keeps the fuse until the job is finished.^[10][11]