Service disconnects and large motor feeders with Class R clips need a 400 A fuse that rides through inrush but still limits fault current. The Littelfuse FLSR400 is a 400 A, 600 V AC Class RK5 dual-element time-delay fuse with a 200,000 A interrupting rating. It is a knife-blade fuse for fused switches, panelboards and switchboards, sold each.
Why electricians pick it
- Dual-element time delay handles motor and transformer inrush.
- Class RK5 fits Class R rejection clips.
- 200 kA AC interrupting rating (20 kA DC).
- Rated 600 V AC and 300 V DC.
- UL listed (E81895) and CSA certified (LR29862).
Specifications
| Spec |
Detail |
| Brand |
Littelfuse |
| Model |
FLSR400 (FLSR series) |
| Class |
UL Class RK5, dual element, time delay, current limiting |
| Amperage |
400 A |
| Voltage |
600 V AC / 300 V DC |
| Interrupting rating |
200 kA AC / 20 kA DC |
| Size |
2-19/32 in dia. x 11-5/8 in, knife blade |
| Certifications |
UL E81895, CSA LR29862 |
| Cross references |
Bussmann FRS-R-400, Mersen TRS400R |
| Sold as |
Each |
Pro tip from the counter
A 400 A knife-blade fuse weighs enough that a small midget-fuse puller will slip off it. Use an insulated puller sized for 61 to 600 A fuses, and only after the switch is open and verified dead; never lever the blade out with a screwdriver, which bends the clip and leaves a hot joint for the new fuse.
Best for: 400 A fused service and distribution switches, large motor feeders, switchboard and panelboard mains, plant maintenance spares
Ships across Canada from Vaughan, ON. Buying a set of three? Ask for a quote or call (905) 553-7171.