# Double spark gap

Canonical URL: https://eloragrid.ai/symbols/iec-double-spark-gap
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: F
Drawing use: Schematic
Reference families: IEC, Manufacturer

## Symbol convention

Convention: IEC
Form: Spark Gap, Double
Autodesk IEC-60617 Symbol Preview: Miscellaneous; vendor family reference, not certified IEC geometry.
Related representation: [Spark-gap protective element](https://eloragrid.ai/symbols/spark-gap-protective-element)

A spark gap form with two gaps sharing a common electrode, used to protect two conductors against a common earth.

## In plain English

### What does Double spark gap mean?

The double spark gap places two gaps in one element, typically from each of two line conductors to a common centre electrode that is earthed. It protects a pair of conductors, such as a telecom pair, with a single component so that both lines are diverted together.

### A simple example

The symbol does not state breakdown voltages or whether both gaps are matched. If one gap breaks down before the other, a transverse voltage can appear across the protected pair. Check the product data where balanced breakdown matters.

### What the drawings help you do

Identify the common electrode connection to earth. Check breakdown matching between the two gaps. A double spark gap protects two conductors to a common electrode; a single spark gap protects one path.

### This particular reference

A spark gap form with two gaps sharing a common electrode, used to protect two conductors against a common earth. A double spark gap protects two conductors to a common electrode; a single spark gap protects one path.

### Terms

- 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)
- [IEC-60617 symbol preview directory](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-7871E6EF-24D5-467E-9B74-321FEDC9DFDA.htm)


## What it represents

The double spark gap places two gaps in one element, typically from each of two line conductors to a common centre electrode that is earthed. It protects a pair of conductors, such as a telecom pair, with a single component so that both lines are diverted together.
The symbol does not state breakdown voltages or whether both gaps are matched. If one gap breaks down before the other, a transverse voltage can appear across the protected pair. Check the product data where balanced breakdown matters.

## How to read it

- Identify the common electrode connection to earth.
- Check breakdown matching between the two gaps.

## Information to show or reference

- Show both line connections and the common earth.
- State breakdown voltage.
- Keep the earth lead short.

## Important distinction

A double spark gap protects two conductors to a common electrode; a single spark gap protects one path.

## Facts

- Graphic cue: Two facing gaps sharing a centre electrode
- Publisher form: Spark Gap, Double (HFU1_S00372 Autodesk identifier)
- Preview: Original educational illustration; consult the publisher and applicable standard for the exact 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 IEC-oriented preview listing the double spark gap form.
- [IEC-60617 symbol preview directory](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-7871E6EF-24D5-467E-9B74-321FEDC9DFDA.htm) — Autodesk. Public directory of IEC-oriented symbol families.

## 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.