Which Types of Fire Extinguisher to Use on Live Electrical Equipment? – UK Guide

Which Fire Extinguisher to Use on Live Electrical Equipment? (UK Guide 2025)

A fire involving live electrical equipment calls for calm, accurate action. The wrong extinguisher can lead to electrocution, equipment damage, or both. This guide explains which extinguisher types are safe, which are not, and why the choice matters in UK workplaces and homes.

UK guidance from the British Approvals for Fire Equipment (BAFE) states clearly: only electrically non-conductive extinguishing media such as carbon dioxide (CO2), dry powder, or clean agents should be used on live electrical equipment. Water and foam, because they conduct electricity, are dangerous and must never be used while equipment remains energised.

The Regulatory Reform (Fire Safety) Order 2005 places a duty on the responsible person to provide and maintain appropriate firefighting equipment. British Standard BS 5306-8:2023 governs the selection, siting, and maintenance of portable extinguishers and is the key reference for choosing the right unit.

Which types of fire extinguisher should you use on live electrical equipment?

Three extinguisher types are considered safe for use on live electrical equipment in the UK: CO2, dry powder, and clean agent extinguishers. Each has advantages and limitations, depending on the environment and the value of the equipment involved.

Extinguisher Type	Colour Code	Suitable for Live Electrical?	Risk of Damage to Equipment	Typical Use Case
CO2 (Carbon Dioxide)	Black	Yes	Low	Server rooms, sensitive electronics
Dry Powder	Blue	Yes	High (residue may corrode)	Industrial, outdoor, no sensitive gear
Clean Agent (e.g., FM-200, Novec 1230)	Varies (often green/special)	Yes	Very low	Data centres, archives
Water / Foam	Red / Cream	No – conductor	Extreme (shock risk)	Never on electrical

Key insights

CO2 extinguishers are the gold standard for live electrical equipment due to non-conductivity and zero residue.
Dry powder extinguishers are safe electrically but can permanently damage sensitive electronics due to corrosive residue.
Clean agent extinguishers (e.g., Novec 1230) are increasingly common in high-value electrical environments.
Never use water, foam, or wet chemical extinguishers on live electrical equipment – risk of electrocution.
The colour code for CO2 extinguishers is black; for dry powder it is blue – this helps quick identification.
BS 5306-8:2023 recommends non-conductive media; always check equipment voltage before acting.

Quick Facts: Fire Extinguishers and Live Electrical Equipment

Fact	Detail
Safe extinguisher types	CO2 (black), Dry powder (blue), Clean agents (special)
Unsafe extinguisher types	Water (red), Foam (cream), Wet chemical (yellow)
Primary risk	Electric shock from conductive extinguishing media
Secondary risk	Equipment damage from powder residue
UK standard	BS 5306-8:2023 governs extinguisher selection
Recommended action	Isolate power if safe, then use CO2

What type of fire extinguisher is used for electrical fire colour?

UK fire extinguishers follow a standardised colour-coding system to aid rapid identification. The colour corresponds to the extinguishing agent inside.

Colour codes for extinguishers suitable for live electrical equipment

CO2 extinguishers are identified by a black label or body. Dry powder extinguishers carry a blue label. Clean agent extinguishers may vary, but often have a green or special marking. The Safelincs blog (2025) notes that CO2 has traditionally been the first choice for electrical fires, partly because its black colour is easy to spot.

Which extinguisher colour for which risk?

Red (water) and cream (foam) extinguishers must never be used on live electrical equipment. Yellow (wet chemical) is designed for cooking oils and fats, not electrical. Blue (dry powder) can be used but with caution indoors due to visibility and residue issues.

Practical identification tip

If you see a black extinguisher in an office or server room, it is likely a CO2 unit – the safest choice for equipment. A blue unit may be dry powder; check the label before use in confined spaces.

Which fire fighting media should you use on liquid fires?

Class B fires involve flammable liquids such as petrol, solvents, and alcohol. The extinguishing media suitable for these fires also overlap with electrical fire protection in some cases.

Foam, CO2, and dry powder for liquid fires

Foam extinguishers are effective on Class B fires but are not suitable for live electrical equipment because foam conducts electricity. CO2 and dry powder are acceptable for both liquid fires and electrical fires, but CO2 is preferred where electronics are present. The IFSEC Global guide (2023) explains that CO2 works by displacing oxygen and leaves no residue, making it ideal for both flammable liquids and energised circuits.

Gaseous fires and the role of clean agents

Fires involving gases (Class C) are typically tackled by dry powder or clean agents. Clean agents such as FM-200 and Novec 1230 are non-conductive and leave minimal residue, making them suitable for both gas fires and sensitive electrical equipment. Their use in portable extinguishers is less common but growing in data centres.

Never use water or foam on live electrical equipment

Water and foam are conductive. Using them on energised equipment creates a direct path for electric current to the user, with potentially fatal consequences. Always isolate power first if safe to do so; then a wider range of extinguishers becomes usable.

Evolution of Electrical Fire Extinguishing Standards

Guidance on which extinguisher to use for electrical fires has changed over time as technology and understanding have advanced. The timeline below shows key milestones.

Pre-2000 – Dry powder was the default recommendation for electrical fires.
2000 – CO2 extinguishers become standard for server rooms and offices.
2010 – Clean agents (FM-200, Novec) gain traction in data centres.
2020 – BS 5306-8 update emphasises non-conductive media for live equipment.
2023 – BS 5306-8:2023 reaffirms CO2, powder, and clean agents; discourages foam on any electrical.
2025 – Latest guidance (Safelincs, BAFE) confirms CO2 as best first-choice for live electrical.

What is certain and what remains unclear about extinguisher use on live electrical equipment?

Some facts are well established, while other areas continue to be debated among fire safety professionals.

Established information	Information that remains unclear
CO2 extinguishers are safe for live electrical equipment (non-conductive).	Whether dry powder is advisable in sensitive environments remains debated – residue can cause long-term corrosion.
Dry powder extinguishers are safe for live electrical equipment but may damage sensitive electronics.	Clean agents are not universally available in portable extinguishers; regulation varies by country.
Water and foam extinguishers must never be used on live electrical equipment.	No single ‘best’ type exists for all situations – depends on equipment value and environment.
The colour code for CO2 is black; for powder it is blue.	Voltage levels (e.g., >1kV) may require different extinguishing media – not all sources agree on threshold.

What does ‘live electrical equipment’ mean in practice?

The phrase ‘live electrical equipment’ implies that the power cannot be isolated. If the equipment is energised, the extinguishing media must not conduct electricity. This is the core principle behind the guidance. If the power can be safely turned off, the fire no longer counts as a live-electrical fire and a wider range of extinguishers, including water or foam, may become appropriate. However, the standard question assumes the equipment remains live, which is the more dangerous scenario.

In the UK, electrical fires are often treated as a separate practical category even though they are not always listed as a formal fire class in every classification system. Some sources still refer to Class E for electrical fires, but workplace guidance focuses on the type of risk rather than a universal class.

What do official sources say about fire extinguishers for live electrical equipment?

Several authoritative bodies provide clear statements on this topic.

“Only electrically non-conductive extinguishing media, such as non-conductive powder, carbon dioxide or clean agent, should be used on live electrical equipment.”

BAFE (British Approvals for Fire Equipment) official FAQ

“CO2 fire extinguishers have traditionally been the first choice for electrical fires.”

Safelincs Blog (2025)

“For electrical fires, CO2 fire extinguishers should be used. By displacing the oxygen in the air, they help to suffocate the fire.”

IFSEC Global Guide (2023)

“Foam extinguishers aren’t normally suitable for putting out electrical fires.”

Red Box Fire Blog (2023)

Which fire extinguisher should you keep for electrical fires?

For most UK settings, a CO2 extinguisher (black label) is the best first-line defence against fires involving live electrical equipment. It is non-conductive, leaves no residue, and is suitable for both electrical fires and Class B flammable liquids. In environments with sensitive electronics, such as server rooms or offices, CO2 is the recommended choice. Dry powder (blue label) can be used but is less preferred indoors. Clean agent extinguishers offer an alternative for high-value equipment. For official compliance, always follow UK Government fire safety guidance and the relevant British Standards.

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Frequently asked questions about fire extinguishers and electrical fires

Which fire class involves flammable liquids like petrol solvents and alcohol?

Class B fires involve flammable liquids such as petrol, solvents, and alcohol. These require foam, dry powder, or CO2 extinguishers, but never water.

Should you test fire extinguisher before use?

Only if you are trained and it is safe to do so. Generally, you should not test a fire extinguisher before use in an emergency – use it directly on the fire. Routine testing should be done during scheduled maintenance.

Can a fire extinguisher blind you?

Yes, direct discharge of dry powder or CO2 into eyes can cause irritation or temporary blindness. Always aim at the base of the fire and maintain distance. Wear protective gear if possible.

Can electrical tape catch fire?

Yes, if it is not rated for the voltage or temperature, or if it degrades over time. Properly rated electrical tape is flame-retardant but can still catch fire under extreme heat or arcing.

Does new equipment need PAT testing?

In the UK, new equipment does not legally require PAT testing before first use if it is purchased from a reputable source and carries CE/UKCA marking. However, a visual inspection is recommended. PAT testing is required after the first use and periodically thereafter.

Is it safe to live near an electrical substation?

Yes, generally. Modern substations are designed with safety in mind and emit low-frequency electromagnetic fields (EMFs) well within international guidelines. However, some people report sensitivity issues, though scientific evidence is inconclusive.

What does the colour code for a CO2 extinguisher look like?

A CO2 extinguisher in the UK has a black label or body. This distinguishes it from water (red), foam (cream), dry powder (blue), and wet chemical (yellow).

Can you use a foam extinguisher on a small electrical fire if the power is off?

If the equipment is isolated and no longer live, foam may be used. But the question assumes the equipment is live; foam is conductive and must never be used on energised circuits.

How often should fire extinguishers be serviced for electrical safety?

BS 5306 recommends a basic inspection monthly and a full service annually by a competent person. CO2 extinguishers require a pressure check every 10 years (hydrostatic test).

Are clean agent extinguishers expensive compared to CO2?

Clean agent extinguishers are generally more expensive than CO2 units. Their use is typically justified in high-value environments such as data centres, where equipment damage from residue must be avoided.