Hammond PFK5 Primary Fuse Kit

Product Description

The HAMMOND PFK5 is a primary fuse kit designed to provide overcurrent protection on the primary side of low-voltage transformers commonly found in HVAC control circuits. Fuse kits of this type limit fault current before it can damage the transformer winding or downstream control components. The PFK5 is installed by licensed HVAC technicians and electricians during new installations or as a retrofit on existing transformer setups that lack primary-side fuse protection. It is a compact, field-installed accessory that adds a critical layer of protection to 24-volt control systems.

This fuse kit is suited for residential and light commercial HVAC applications where a step-down transformer supplies 24-volt control voltage to thermostats, contactors, and control boards. It is typically installed inline on the primary winding leads of the transformer inside an air handler, furnace, or packaged unit control panel. Technicians add this kit when upgrading aging equipment or when a system has experienced repeated transformer failures due to secondary-side shorts.

Key Features

• Provides primary-side overcurrent protection for low-voltage HVAC transformers
• Helps prevent transformer burnout caused by secondary circuit faults
• Designed for field installation on existing or new transformer setups
• Compact form factor fits inside standard HVAC control compartments

Compatibility

Designed as an OEM-style primary fuse kit for use with low-voltage control transformers in residential and light commercial HVAC systems.

Installation Notes

Installation should be performed by a licensed HVAC technician or electrician. Disconnect and lock out all power to the unit before servicing the control panel or handling transformer wiring. Follow applicable NEC requirements for overcurrent protection and conductor sizing. Do not bypass or replace the fuse with a higher-rated substitute.

Technical Specifications

• UPC: 80342307777

Standard Information

• Brand: HAMMOND
• Manufacturer Part Number: PFK5