Lawson TBC63M100 63 Amp BS88 100 amp Motor Rated HRC Fuse

The first rating is the continuous Current and the second is the Motor Starting Current

See motor rating chart below on product files

To avoid nuisance fuse-link operation due to overcurrent starting surges, fuse-links used in motor circuits often require higher ratings than the full load current of the motor. Motor circuit protection fuse-links have a dual current rating, consisting of a continuous current rating and a rating relating to the operational characteristics. The letter ‘M’ separates these two ratings, for example, 63M100. This represents a fuse-link with a maximum continuous current rating of 63Amps, and an operational characteristic of 100 Amps rating to meet the motor starting current.