Eaton FH55 Thermal Unit 30.90-33.30 Amps

Eaton FH55 Thermal Unit

The Eaton FH55 is a bimetallic thermal overload unit designed for NEMA Size 2 motor starters. It provides Trip Class 20 protection for full-load currents between 0.25 and 0.27 amps or 0.29 and 0.31 amps. The transparent housing allows visual inspection of the internal mechanism. It suits maintenance teams replacing worn units in compatible Series A200 or B100 starters.

Replaces original thermal units

This unit directly replaces the original thermal elements in Eaton Series A200 and B100 starters when the trip rating matches the motor full-load current. The jump is worth it when the existing element has tripped repeatedly, shows discoloration, or no longer holds the correct calibration. It restores the intended overload protection without changing the starter enclosure or wiring.

Check starter model and current rating

Verify the starter nameplate lists a compatible model such as B100J0B, B100M1C, or B100W0C before ordering. Confirm the motor full-load current falls within either the 0.25 to 0.27 A or 0.29 to 0.31 A range marked on the unit. Installing a unit with the wrong trip range will cause nuisance tripping or leave the motor unprotected.