Cutler Hammer 10316H621C Type L Overload Relay / Control Component

The Cutler Hammer 10316H621C is a component from the Type L series of industrial control devices, originally manufactured by Cutler-Hammer (now part of Eaton Corporation). Based on the part number pattern, this device is most likely a bimetallic overload relay designed for motor protection, or an auxiliary contact block for contactors. The "Type L" designation refers to a line of reliable electromagnetic and thermal devices used in motor control centers (MCCs) and across industrial machinery. This specific model is rated for 600V AC systems and provides adjustable trip characteristics.

Typical Specifications (Derived from Type L Series)

• Catalog Number: 10316H621C

• Series: Type L

• Function: Overload relay (thermal) or control relay

• Poles: 3 pole (for overload) or 2-4 pole (for auxiliary)

• Rated Operational Voltage: 600V AC max

• Trip Class: Class 10, 15, or 20 adjustable (depending on heater selection)

• Auxiliary Contact Configuration: Typically 1 NO + 1 NC (for overload relay version)

• Reset Method: Manual or automatic (selectable)

• Mounting: Direct to Cutler Hammer A200 or C300 contactors

Functional Description

If this component is an overload relay, it contains three bimetallic strips (one per phase) that heat up in response to motor current. Under sustained overcurrent, the bimetal bends and releases a trip mechanism, opening a normally closed control circuit contact that shuts down the contactor. The 10316H621C uses interchangeable heater elements to match different motor full-load amperes (FLA). The "621" in the part number may indicate a specific heater size or trip rating. The device includes a manual reset button with a "trip-free" mechanism that prevents holding the reset closed during a fault condition.

Alternative Identification as Control Relay

Some Type L devices are general-purpose control relays with 4-pole configurations (2 NO + 2 NC or 3 NO + 1 NC). The 10316H621C could be a relay with 600V AC coils (e.g., 120V, 240V, or 480V coil voltage). The coil voltage would be indicated by suffix letters not fully shown; further factory documentation is needed. In this role, it would be used for interposing, logic, or auxiliary functions in motor starters and control panels.

Applications

Typical applications include motor starter overload protection for pumps, fans, compressors, and conveyors. The Type L overload relay is commonly paired with Cutler Hammer A200 or C300 size contactors in NEMA motor starters. It can also be used as a standalone thermal protector in distribution panels.

Mechanical Data

Dimensions: approx. 90mm height x 45mm width x 80mm depth. Weight: 0.3 kg. Terminals accept wire up to 12 AWG. Operating temperature: -20°C to +60°C. The housing is thermoset plastic with V-0 flammability rating. The device has IP20 finger-safe terminals when installed in an enclosure.

Standards and Compliance

Meets NEMA ICS 2 (industrial control devices) and UL 60947-4-1. CE marked for European use. The device is RoHS compliant.

Replacement and Interchangeability

The 10316H621C is obsolete as original Cutler Hammer production; Eaton still produces Type L replacement parts under newer catalog numbers. For exact replacement, consult Eaton cross-reference documents. Heater packs are still available as Type L heater elements (e.g., H1018 series).

Installation Notes

When installing, ensure the correct heater element is installed for the motor FLA. For overload relay use, wire all three phase conductors through the current sensing holes (if integral) or connect external CTs. Do not use the relay to directly switch power; it must control the contactor coil circuit.

Conclusion

The Cutler Hammer 10316H621C Type L device, whether used as an overload relay or control relay, represents a rugged, industry-standard component for motor protection and control logic in legacy installations and panel retrofits.