# Surge arrester counter

Canonical URL: https://eloragrid.ai/symbols/surge-arrester-counter
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: SC
Drawing use: SLD, Schematic
Reference families: Manufacturer

Counter in a surge arrester's earth lead that registers discharges and often shows leakage current.

## In plain English

### What does Surge arrester counter mean?

A surge counter is installed in the earth connection of a surge arrester, which must therefore be mounted on an insulating base. It increments each time the arrester discharges a significant surge, and many models include a milliammeter for leakage current, which helps assess arrester condition.

### A simple example

On single-line diagrams the counter is drawn between the arrester and earth. The symbol does not tell you the counting threshold or whether leakage reading is total or resistive, and the insulating base must be shown so the counter is not bypassed.

### What the drawings help you do

Check the arrester is on an insulating base. Note whether leakage current is shown. A surge counter records arrester operations; the surge arrester itself diverts the surge.

### This particular reference

Counter in a surge arrester's earth lead that registers discharges and often shows leakage current. A surge counter records arrester operations; the surge arrester itself diverts the surge.

### Terms

- Terminal: An identified point where a conductor connects.
- Rating: A value stating the conditions for which equipment is specified.
- Schematic: A drawing showing function and connections rather than physical appearance.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [AutoCAD Electrical: Earthing, sources and surge protection](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-1E3FDEAE-B4B2-417C-8075-108AA2C6E509.htm)


## What it represents

A surge counter is installed in the earth connection of a surge arrester, which must therefore be mounted on an insulating base. It increments each time the arrester discharges a significant surge, and many models include a milliammeter for leakage current, which helps assess arrester condition.
On single-line diagrams the counter is drawn between the arrester and earth. The symbol does not tell you the counting threshold or whether leakage reading is total or resistive, and the insulating base must be shown so the counter is not bypassed.

## How to read it

- Check the arrester is on an insulating base.
- Note whether leakage current is shown.

## Information to show or reference

- Show counter in earth lead
- Show insulating base
- State counting threshold

## Important distinction

A surge counter records arrester operations; the surge arrester itself diverts the surge.

## Facts

- Location: Arrester earth lead
- Readings: Discharge count and often leakage current
- Preview: Functional illustration of the device role; not a product footprint or certified standard graphic

## Public references

- [AutoCAD Electrical: Earthing, sources and surge protection](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-1E3FDEAE-B4B2-417C-8075-108AA2C6E509.htm) — Autodesk. Public AutoCAD Electrical earthing and surge protection symbol family.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.