Single Phase Surge Arrester for Transformer Low-Voltage Side Protection

Single Phase Surge Arrester by Prosurge: Transformer Low-Voltage Side Protection

Electrical distribution transformers face constant risks from lightning strikes and switching transients. 

A single phase surge arrester from Prosurge provides the necessary protection for the low-voltage 

secondary side of pole-mounted and pad-mounted transformers. 

The Prosurge PSM40 series single phase surge arrester is designed specifically for this application, 

delivering 40kA max discharge current (8/20µs) and compliance with UL1449 5th Edition and

IEEE Std C62.11.

The Prosurge single phase surge arrester uses UL-certified high-performance MOVs as core components.

This Prosurge single phase surge arrester achieves low voltage protection levels and 

fast ≤25ns response time. Each Prosurge single phase surge arrester in the series maintains 

leakage current below 0.1mA and requires no follow current.

Three Voltage Configurations from Prosurge

A single phase surge arrester must match the operating voltage of the protected transformer.

 Prosurge offers three distinct single phase surge arrester models in the PSM40 series.

The Prosurge PSM40-240/2P single phase surge arrester is designed for 120/240Vac split phase

 power systems, with a max continuous operating voltage (Uc) of 275Vac. 

This Prosurge single phase surge arrester achieves a voltage protection level below 1.8kV 

at 20kA and withstands temporary overvoltage (TOV) of 335Vac for 5 seconds.

The Prosurge PSM40-480/2P single phase surge arrester is designed for 240/480Vac split phase 

power systems, with a max continuous operating voltage (Uc) of 480Vac. 

This Prosurge single phase surge arrester delivers voltage protection below 2.0kV at 20kA and 

handles TOV of 504Vac for 5 seconds.

The Prosurge PSM40-277/S single phase surge arrester is designed for 277Vac single phase power systems, 

with a max continuous operating voltage (Uc) of 650Vac. This Prosurge single phase surge arrester 

achieves voltage protection levels of <2.4kV at 5kA, <2.6kV at 10kA, and <3.2kV at 20kA.

Rugged Construction for Outdoor Transformer Installation

A single phase surge arrester installed on a pole or pad transformer must survive harsh environmental 

exposure. Prosurge builds the PSM40 series single phase surge arrester using high-grade 304 stainless 

steel housing with IP68 (NEMA6P) rating. This Prosurge single phase surge arrester enclosure is both 

waterproof and flame-resistant, ensuring long-term reliability from –40°C to +85°C.

The Prosurge single phase surge arrester arrives pre-wired with 30cm UL1015 10AWG leads. Each Prosurge 

single phase surge arrester includes lug terminals (5.5-12) for direct connection to the transformer 

low-voltage side phase and neutral (or ground). Installation requires only basic tools and screws for 

mounting.

Why Choose Prosurge Single Phase Surge Arrester

Selecting a single phase surge arrester with UL1449 5th Edition certification guarantees compliance with

 the latest safety standards. Each Prosurge single phase surge arrester undergoes rigorous testing to verify 

40kA Imax, 5kA In, and 10kV Uoc ratings. The epoxy resin encapsulation of each Prosurge single phase surge

 arrester provides excellent insulation and mechanical strength.

The Prosurge single phase surge arrester family is task-rated as Light Duty per UL1449, making this 

Prosurge single phase surge arrester ideal for transformer low-voltage side protection. Contact Prosurge 

technical team to select the correct single phase surge arrester for your specific transformer application.