Eaton
Eaton FH45 Thermal Unit Trip Class 20
Thermal overload unit rated for 12.7 to 17.2 A with Trip Class 20, compatible with NEMA sizes 0, 1, 2 and Series A200, B100 starters
- TypeIndustrial Electrical Controls & Automation
- ColorTransparent
- Reliable motor protection with Trip Class 20 thermal response
- Precise overload safeguard across 12.7 to 17.2 A current ranges
- Broad compatibility with NEMA Size 0, 1, 2 starters
- Direct fit for Series A200 and B100 contactors
- Cross-references 11 Grainger part numbers for easy replacement
Eaton FH45 Thermal Unit Overview
The Eaton FH45 thermal unit provides overload protection for industrial motor starters. It is designed for NEMA Size 0, 1, and 2 controllers and operates at Trip Class 20. Maintenance teams and panel builders use it to replace worn elements in compatible Series A200 and B100 equipment.
Thermal Behaviour and Power Characteristics
The transparent housing allows visual confirmation of the element condition during routine checks. Multiple full-load current ranges from 12.7 to 17.2 amperes cover several motor sizes within the supported NEMA frames. The thermal mechanism responds to sustained overcurrent without external power or control wiring.
Sustained Load Performance
Trip Class 20 timing lets the unit tolerate typical motor starting currents while still protecting windings during prolonged overloads. The calibrated bimetal construction maintains consistent trip points over repeated heating cycles. It fits the listed Grainger part numbers 11Z488 through 11Z497 and 12M44 through 12M47 for direct drop-in replacement.
Highlights
- Reliable motor protection with Trip Class 20 thermal response
- Precise overload safeguard across 12.7 to 17.2 A current ranges
- Broad compatibility with NEMA Size 0, 1, 2 starters
- Direct fit for Series A200 and B100 contactors
- Cross-references 11 Grainger part numbers for easy replacement
Specifications
| Brand | Eaton |
|---|---|
| Type | Industrial Electrical Controls & Automation |
| Color | Transparent |
Questions about this item
How do I install the Eaton FH45 thermal unit in a Series A200 starter, and which step is commonly missed?
Snap the unit into the overload relay base for NEMA Size 0, 1, or 2 starters, then verify the full-load current range — 12.7 to 13.8 A, 13.6 to 14.9 A, 15.4 to 16.6 A, or 15.8 to 17.2 A — matches the motor nameplate; the missed step is confirming the correct range before closing the cover.
What maintenance or replacement will the Eaton FH45 thermal unit need after it trips?
The thermal unit is a single-use Trip Class 20 device; once it operates it must be replaced with a new FH45 unit of the same current range — 12.7 to 13.8 A, 13.6 to 14.9 A, 15.4 to 16.6 A, or 15.8 to 17.2 A — because the bimetal element cannot be reset.
What is the first limit reached by the Eaton FH45 thermal unit under sustained overload?
The Trip Class 20 rating means the unit will trip within 20 seconds at six times the rated current; that thermal-time limit is reached before any mechanical or insulation limit in the NEMA Size 0, 1, or 2 starter.
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