High voltage symbol

A black lightning arrow in a yellow triangle, warning of electrical danger.

Also known as: Electric shock symbol, Lightning bolt warning, Electrical hazard symbol, ISO 7010 W012

Everyday & digitalSafety & hazardStandard profile

Meanings

A jagged arrow in a yellow triangle warns of dangerous voltage. The arrowhead matters: it distinguishes the hazard warning from the plain zigzag used decoratively to mean electricity in general.

Common modern usageVerified fact
Warns of dangerous electrical voltage behind a panel, inside an enclosure, or in an area.
Contexts: Public information
Common modern usageVerified fact
Is drawn as an arrow rather than a plain zigzag — the arrowhead marks it as the hazard symbol, distinguishing it from decorative or generic uses of a lightning shape to mean electricity.
Contexts: Public information
Common modern usageCommon usage
Appears in some jurisdictions with wording such as 'Danger of Death', which is a local addition to the pictogram rather than part of it.
Contexts: Public information
Common modern usageVerified fact
Belongs to the warning class of safety signs, drawn as a black pictogram in a yellow triangle with a black border. The triangle means a hazard is present and care is needed, not that anything is prohibited.
Contexts: Public information
Officially standardisedVerified fact
Is registered in ISO 7010 as W012, warning: electricity, and follows the warning convention — a black pictogram on a yellow triangle with a black border. The arrow-headed flash points down and to the right.
Contexts: Public information, Electrical equipment
Common modern usageVerified fact
Is seen on substation fencing, distribution cabinets, transformer housings, equipment covers and the inside of appliance casings. On consumer equipment it usually marks a part that stays live after the power is switched off, which is why it appears next to capacitors and inside power supplies rather than on the outside of the case.
Contexts: Public information, Electrical equipment

Visual description

A jagged black arrow shaped like a lightning stroke, angled downward with a clear arrowhead, inside a black-bordered yellow triangle.

Symmetry: none
Orientation: upright
Colours: yellow, black

Part of the same system as: General warning symbol
Both are yellow-triangle warning signs; this one names the hazard the general sign leaves unstated.

Confidence

IdentityHigh confidence: High confidence because the identity is defined by a current official standard, but multiple independent sources agree.
Historical originLow confidence: Low confidence because the historical origin is documented in encyclopedic references, but only a single source has been found so far, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is documented in encyclopedic references.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references.

Sources

Safety sign
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for what the symbol depicts, its shape-and-colour category, and any ISO reference number it reports. The standards themselves are paywalled and were not consulted, so nothing here is treated as an official definition.
ISO 3864, Graphical symbols — Safety colours and safety signs
International Organization for Standardization · retrieved 2026-08-22
Paywalled and NOT READ in full. Registered so records can state that the safety-sign colour and shape conventions — green for safe condition, red for prohibition and fire equipment, yellow for warning, blue for mandatory action — are set by a standard rather than by convention. See docs/paywalled-standards.md.
High voltage
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for what the symbol depicts, its shape-and-colour category, and any ISO reference number it reports. The standards themselves are paywalled and were not consulted, so nothing here is treated as an official definition.
ISO 7010, Graphical symbols — Safety colours and safety signs
International Organization for Standardization · retrieved 2026-08-02
Paywalled and NOT READ in full. Registered so records can state that a sign has a standard reference and a defined shape and colour — E003 for first aid, E010 for a defibrillator. The catalogue of registered signs and their reference numbers is public even where the standard text is not. See docs/paywalled-standards.md.

Last reviewed 2026-08-22

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Safety signs and their shape-and-colour grammar

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Meanings

A jagged arrow in a yellow triangle warns of dangerous voltage. The arrowhead matters: it distinguishes the hazard warning from the plain zigzag used decoratively to mean electricity in general.

Common modern usageVerified fact

Warns of dangerous electrical voltage behind a panel, inside an enclosure, or in an area.

Contexts: Public information

Common modern usageVerified fact

Is drawn as an arrow rather than a plain zigzag — the arrowhead marks it as the hazard symbol, distinguishing it from decorative or generic uses of a lightning shape to mean electricity.

Contexts: Public information

Common modern usageCommon usage

Appears in some jurisdictions with wording such as 'Danger of Death', which is a local addition to the pictogram rather than part of it.

Contexts: Public information

Common modern usageVerified fact

Belongs to the warning class of safety signs, drawn as a black pictogram in a yellow triangle with a black border. The triangle means a hazard is present and care is needed, not that anything is prohibited.

Contexts: Public information

Officially standardisedVerified fact

Is registered in ISO 7010 as W012, warning: electricity, and follows the warning convention — a black pictogram on a yellow triangle with a black border. The arrow-headed flash points down and to the right.

Contexts: Public information, Electrical equipment

Common modern usageVerified fact

Is seen on substation fencing, distribution cabinets, transformer housings, equipment covers and the inside of appliance casings. On consumer equipment it usually marks a part that stays live after the power is switched off, which is why it appears next to capacitors and inside power supplies rather than on the outside of the case.

Contexts: Public information, Electrical equipment

Confidence

IdentityHigh confidence: High confidence because the identity is defined by a current official standard, but multiple independent sources agree.
Historical originLow confidence: Low confidence because the historical origin is documented in encyclopedic references, but only a single source has been found so far, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is documented in encyclopedic references.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references.

Sources

Safety sign
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for what the symbol depicts, its shape-and-colour category, and any ISO reference number it reports. The standards themselves are paywalled and were not consulted, so nothing here is treated as an official definition.
ISO 3864, Graphical symbols — Safety colours and safety signs
International Organization for Standardization · retrieved 2026-08-22
Paywalled and NOT READ in full. Registered so records can state that the safety-sign colour and shape conventions — green for safe condition, red for prohibition and fire equipment, yellow for warning, blue for mandatory action — are set by a standard rather than by convention. See docs/paywalled-standards.md.
High voltage
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for what the symbol depicts, its shape-and-colour category, and any ISO reference number it reports. The standards themselves are paywalled and were not consulted, so nothing here is treated as an official definition.
ISO 7010, Graphical symbols — Safety colours and safety signs
International Organization for Standardization · retrieved 2026-08-02
Paywalled and NOT READ in full. Registered so records can state that a sign has a standard reference and a defined shape and colour — E003 for first aid, E010 for a defibrillator. The catalogue of registered signs and their reference numbers is public even where the standard text is not. See docs/paywalled-standards.md.

Last reviewed 2026-08-22

Meanings

Visual description

Related & commonly confused symbols

Meanings

Visual description

Related & commonly confused symbols