WHEN YOUR HEAVIER LOADS NEED PROTECTION A4BT FUSES WON'T LET YOU DOWN The high interrupting rating of A4BT current limiting fuses is ideally suited for protecting mains, feeders, and general circuits. The 10-second time delay at 500% of fuse rating is ideal for large motors and other loads with a high inrush. A4BT fuses are suitable for DC applications up to 500VDC. An A4BT fuse can be applied to normal loads up to its full ampere rating to allow 100% rating of equipment.