B&W Fire Blog

Fire extinguishers are categorized into five basic classes: A, B, C, D, and K. Each class is designed to tackle specific types of fires.

Class C fires, for instance, involve energized electrical equipment and demand specialized tools, namely Class C fire extinguishers. This article will guide you through everything you need to know about Class C fire extinguishers, what makes Class C fires unique, and how to ensure you’re prepared.

What is a Class C Fire?

A Class C fire is a fire that involves energized electrical equipment. Think of common items like wiring, circuit breakers, appliances, or even large machinery. If the equipment is plugged in or connected to a power source when it catches fire, it’s considered a Class C fire.

These fires often start due to issues like:

• Faulty wiring
• Short circuits
• Overloaded outlets or extension cords
• Overheated electrical equipment

The key characteristic of a Class C fire is the presence of electricity. This presents a significant hazard because using the wrong type of extinguisher, especially one containing water, could lead to electrical shock for the person trying to put out the fire. That’s why specialized Class C fire extinguishers are necessary.

They use non-conductive extinguishing agents specifically designed to prevent electrical shock. Due to the dual threat of fire and electricity, Class C fires are particularly hazardous and require immediate and careful attention to prevent property damage and serious injury.

Which Extinguishers Work on Electrical Fires?

When dealing with fires involving energized electrical equipment, only Class C rated fire extinguishers should be used. These extinguishers are specifically designed and rated to safely combat electrical fires. There are a few common types of extinguishers suitable for Class C fires:

• Dry Chemical Extinguishers: These are often multi-purpose (e.g., ABC rated) and use fine powders to smother the flames. The dry chemical agent interrupts the chemical reaction of the fire and creates a barrier between the fuel and oxygen.
• Clean Agent Extinguishers: These extinguishers use agents that are electrically non-conductive and do not leave behind a messy residue, making them ideal for protecting sensitive electronic equipment like computers or servers.
• Carbon Dioxide (CO2) Extinguishers: These extinguishers release carbon dioxide gas, which displaces the oxygen around the fire, effectively suffocating it. CO2 is also very cold, which helps to cool the burning material. Like clean agents, CO2 does not leave a residue.

It’s crucial to remember that water-based extinguishing agents cannot be used on Class C fires because they conduct electrical current, posing a severe risk of electrocution.

What Are Class C Fire Extinguishers Used For?

Class C fire extinguishers are specifically designed for fighting fires that involve energized electrical equipment. Their non-conductive agents make them safe to use without the risk of electrical shock.

You’ll typically find Class C extinguishers in locations where electrical hazards are present, such as:

• Offices with computers, servers, and other electronics
• Commercial kitchens with numerous electrical appliances
• Data centers and server rooms
• Industrial settings with electrical machinery
• Residential areas with televisions, computers, and various appliances

These extinguishers are used to put out fires that involve energized electrical equipment. This means things that are plugged in or connected to a power source. Examples include common items like computers, TVs, and appliances, but also wiring, circuit breakers, power tools, and electric motors. It also covers important parts of electrical systems like transformers, switchgear, and control panels.

Having a Class C fire extinguisher readily accessible is an essential component of any comprehensive fire safety plan, especially in areas with a high concentration of electrical devices.

Other Fire Types You Should Know About

Understanding the differences between fire classes is vital for choosing the correct extinguisher and ensuring safety. Here’s how Class C fires compare to other common types:

• Class A Fires: These involve ordinary combustible materials such as wood, paper, cloth, rubber, and many plastics. Water or foam extinguishers are often used for Class A fires.
• Class B Fires: These fires involve flammable liquids like gasoline, petroleum greases, oil-based paints, solvents, and flammable gases. Smothering agents like dry chemical, CO2, or foam are effective.
• Class D Fires: These are less common and involve combustible metals such as magnesium, titanium, sodium, or potassium. They require special dry powder extinguishing agents specifically designed for the type of metal involved.
• Class K Fires: These fires involve vegetable oils, animal oils, or fats in commercial cooking appliances found in restaurant kitchens. Wet chemical extinguishers are typically used for Class K fires.

Using the wrong type of fire extinguisher can have devastating consequences, potentially making the fire worse or creating new hazards. For example, using a water extinguisher on a Class B flammable liquid fire could spread the fire, and using it on a Class C electrical fire could cause electrocution.

How to Safely Deal With a Class C Fire

When faced with a Class C fire, safety is paramount. Here are crucial precautions to take:

1. De-energize the Equipment: If it’s safe to do so, the first and most important step is to turn off or disconnect the power source to the burning electrical equipment. This removes the “C” classification, and the fire might then be treated as a Class A or B fire, depending on what is burning. However, always assume it’s energized if you are unsure.
2. Evacuate the Area: Ensure everyone is safely out of the immediate vicinity of the fire.
3. Call the Fire Department: Alert emergency services immediately, even if you think you can handle the fire. Fires can escalate quickly.
4. Use the Correct Extinguisher: Only use a fire extinguisher rated for Class C fires on energized electrical equipment.
5. Follow the P.A.S.S. Method: If you are trained and it’s safe to use an extinguisher:
   • Pull the pin.
   • Aim the nozzle at the base of the fire.
   • Squeeze the lever slowly and evenly.
   • Sweep the nozzle from side to side.
6. Maintain a Safe Distance: Stand back from the fire as recommended by the extinguisher’s instructions.
7. Ensure an Escape Route: Always keep an escape route behind you when attempting to extinguish a fire.

Do You Need a Class C Fire Extinguisher?

Deciding if you need a Class C fire extinguisher depends on the types of fire hazards present in your environment. Extinguishers should be selected based on the specific risks. Here are some scenarios where a Class C fire extinguisher is essential:

• You operate an office: If your workspace has computers, printers, servers, and other electronic devices, a Class C rated extinguisher is necessary.
• Your facility includes a server room or data center: These areas, packed with sensitive and energized electrical equipment, absolutely require Class C protection, often with clean agents to prevent damage to electronics.
• You have workshops with electrically powered tools and machinery: Power tools, welding equipment (if electric), and other machinery pose a Class C fire risk when energized.
• Your commercial kitchen uses various electrical appliances: While Class K extinguishers are vital for cooking oil fires, many electrical appliances in a commercial kitchen also necessitate Class C coverage.
• You manage a building with significant electrical infrastructure: Areas with electrical panels, circuit breakers, transformers, and control rooms need Class C extinguishers.
• Your home contains typical household electronics: Televisions, computers, entertainment systems, and kitchen appliances all represent potential Class C fire sources. A multi-purpose ABC 

Choosing the right fire extinguisher for your specific needs is crucial. Using the wrong type can be ineffective and even dangerous. If you’re unsure, consulting with a fire safety professional is always a good idea.

Your Next Steps for Enhanced Fire Safety

Class C fire extinguishers are specifically designed to combat fires involving energized electrical equipment, making them a vital part of any fire safety plan where such hazards exist. By recognizing the unique dangers of electrical fires and preparing accordingly, you can better protect lives and property.

If you have questions about Class C fire extinguishers or need assistance with your fire safety plan, including sales, inspection, or maintenance services, we’re here to help.

Contact us today at B & W Fire Security Systems to ensure your facility is equipped and prepared.

Frequently Asked Questions

What is a Class C fire?

A Class C fire involves energized electrical equipment such as wiring, circuit breakers, appliances, or machinery that is plugged in or connected to a power source when it ignites. The presence of electricity is the key characteristic, posing a shock hazard if handled incorrectly.

What is a Class C fire extinguisher used for?

Class C fire extinguishers are used to fight fires involving energized electrical equipment. They use non-conductive extinguishing agents, which prevent electrical shock to the operator during use.

What types of extinguishers are safe for electrical fires?

Only fire extinguishers rated as Class C are safe for electrical fires. Common types suitable for Class C fires include dry chemical extinguishers (often ABC rated), clean agent extinguishers, and carbon dioxide (CO2) extinguishers.

Can I use a water extinguisher on an electrical fire?

No, you must never use a water-based extinguisher on a Class C fire. Water conducts electricity and using it on an energized electrical fire can lead to severe electrical shock and potentially spread the fire.

What should I do first if I see an electrical fire?

If it is safe to do so, the first and most crucial step is to de-energize the equipment by turning off or disconnecting its power source. After ensuring your safety, evacuate the area and call the fire department immediately.

How often do Class C fire extinguishers need to be checked?

Class C fire extinguishers should undergo a visual inspection at least once a month by the owner or a designated person. Additionally, they require professional maintenance annually by a certified technician and periodic hydrostatic testing according to regulations.

Where are Class C fire extinguishers typically needed?

Class C extinguishers are essential in any location with electrical hazards. This includes offices with computers and servers, data centers, industrial settings with electrical machinery, commercial kitchens, and even homes with various electronic appliances.

How do I use a fire extinguisher on a Class C fire?

If you are trained and it is safe, use the P.A.S.S. method: Pull the pin, Aim the nozzle at the base of the fire, Squeeze the lever slowly and evenly, and Sweep the nozzle from side to side. Always ensure you have a clear escape route behind you.