# Eaton Cooper Power VariSTAR Neutral Grounding Surge Arrester

> surge-arrester - UltraSIL polymer-housed intermediate-class metal-oxide surge arrester designed for power transformer neutral grounding, grounding resistor protection and substation insulation coordination.

**Voltformer canonical:** https://voltformer.com/product/eaton-cooper-power-varistar-neutral-grounding-surge-arrester - markdown version: https://voltformer.com/product/eaton-cooper-power-varistar-neutral-grounding-surge-arrester.md

## Overview

- **Brand:** Eaton Cooper Power
- **Product family:** VariSTAR intermediate surge arresters
- **Category:** Grid Equipment & Power Quality / surge-arresters-and-insulation-coordination

## Manufacturer-stated technical envelope

- **System voltage:** 3.6–72.5 kV
- **Rated voltage:** 3–60 kV
- **Nominal discharge current:** 10 kA peak
- **Line discharge class:** 1 / 2
- **Mechanical strength (SSL):** 400 / 800 Nm
- **Housing:** UltraSIL silicone polymer housing with high energy metal oxide varistor disks for neutral grounding and transient protection

## Standards

- IEEE C62.11
- IEC 60099-4

## Official sources

- https://www.eaton.com/us/en-us/catalog/surge-protection-devices/varistar-type-ui-normal-duty-intermediate-class-surge-arresters.html

- **Source scope:** manufacturer-family
- **Last reviewed:** 2026-09-16

Eaton Cooper Power VariSTAR UI polymer-housed surge arrester family data for transformer neutral grounding and insulation coordination. Verify nominal discharge current and MCOV for site conditions.

The stated values are family or catalogue-option limits. Select the exact order code and verify project-specific duties before procurement or release of an SLD design.