Electrical Fire Protection

What Causes Electrical Fires?

A great place to begin is by asking the question: how do electrical fires start? In non-home spaces, electrical fires are caused by the following:

75% by electrical failure or malfunction
9% by mechanical failure or malfunction
6% by combustible material too near a heat source
2% by overloaded equipment
13% by other causes

Of the 75% of fires caused by electrical malfunction or failure, nearly half are related to arcing. So— What is an electric arc? Electrical arcing occurs when a current jumps across a gap between conductive materials. This arc can reach temperatures of over 10,000 degrees Fahrenheit and combust flammable gases, dust particles, or other materials it encounters.

What Is Considered an Electrical Fire?

An electrical fire is any fire that includes live currents or electric equipment. These types of fires are more common in industrial settings that have higher volumes of high-powered electrical equipment like transformers, electric tools, appliances, and motors.

Normally, electric fires cannot be extinguished with water, because the conductive nature of water could make the electrical fire spread or become more intense. Instead, electric fires should be suppressed with non-conductive agents to minimize damage and risk.

Different countries classify fire types differently. Electrical fires are considered:

Class C fires in the USA
Class E fires in Australia
Unclassified (based on fuel type) in EU and India

It is helpful to understand the necessary ingredients for a fire to burn. Oxygen, heat, and fuel are commonly known as the fire triangle because fires require these three elements to ignite and burn. Depriving a fire of any or all of these will stop it. The different methods of fire suppression discussed later in this article will rely on depriving a fire of one or several of these necessary components.

Oxygen is required for the combustion reaction that is fire. Most fire suppression works by depriving fire of oxygen, thus stopping this reaction. This can be done with fire suppressants like inert gases. For example, ABC dry chemical forms a "crust" over a combustible material to separate the fuel from oxygen. Foams act in a similar way to split up the fuel from the oxygen.
Heat is needed for fire ignition, and each material has a different temperature at which it will burn. Many types of fires can be suppressed if materials are cooled below this temperature, often with water.
Fuel is the material that is burning in a fire. Electric fires are ignited by electricity, but can involve any kind of fuel, depending on what flammable material is nearby. Usually, once a fire has started, it is too late to safely remove fuel, so it is important to make sure flammable materials are not stored near high-risk areas.

How Long Does it Take for an Electrical Fire to Start?

Electrical fires can start almost instantly, take years to develop, or begin in any amount of time in between.

In seconds an electrical arc can combust flammable material or gases—causing a fire almost instantly.
In minutes an electrical heater can tip onto a flammable carpet and produce enough heat for it to burn.
In hours an overloaded electrical cord could heat a stack of papers nearby to produce a flame.
In days, months, or years a damaged wire along a wooden beam could char and smolder the flammable wood before eventually leading to a fire.

How to Prevent Electrical Fires in the Workplace

The high cost and known causes of electrical fires in commercial and industrial settings highlight the importance of fire safety at the workplace. As discussed above, there are several electrical fire hazards that are most likely to cause a workplace fire. Let’s look at each and find out how to prevent electrical fires.

Electrical or mechanical malfunction or failure
- Regularly monitor inspect electric and non-electric components of buildings and equipment for wear or damage.
- Repair or replace worn and damaged elements of facilities and equipment immediately.
- Provide easy ways for staff to report any safety concerns.

Overloaded equipment and flammable material near heat
- Provide training and labeling for all electrical equipment to educate staff about risks.
- Regularly monitor inspect the workplace for accidental overloading or misplacement.
- Upgrade equipment as appropriate for less heat production and increased fire safety features.

Workplaces must prioritize designating specific measures like these to protect against electrical fires. In addition to these necessary steps, consider using other devices designed to increase electrical safety and reduce the risk of electrical fires. These include GFCI outlets and surge protectors.

Will GFCI Prevent Fire?

A ground fault circuit interrupter (GFCI) is an electrical device that can either be installed as part of an outlet or electrical system, or onto a power cord for a specific device. The main purpose of these devices is to prevent electrical shock in an individual if their body were to unintentionally complete an electric circuit due to faulty equipment or an accident.

Although they were not designed primarily as a way to prevent electrical fires, GFCIs can reduce electrical fire risks in very specific scenarios due to their ability to cut power in circuits in the case of low current grounding faults. In some wiring cases, the grounding wire is placed between the neutral and hot conductors. If damaged, this cable could then contain two conductors running parallel to each other with only an air gap between them. If an arc occurs across this gap, a GFCI device will shut off power much sooner than a circuit breaker would (at 6 vs. 40 amperes), significantly reducing the chance of fire in this situation.

Can Surge Protectors Prevent Electrical Fires?

Properly used and maintained surge protectors can reduce the risk of fire caused by sparking appliances due to power surges. The main purpose of a surge protector is to safeguard the electrical devices plugged into it from damage from electrical surges. Power surges are increases in electric voltage caused by lightning strikes, power restoration after an outage, faulty wiring, overloading of circuits, and more.

Surge protectors shield electronics by cutting power to an outlet when a larger-than-normal electric voltage is detected. If an outlet experiencing a power surge remains on, it could overwhelm whatever devices are plugged into it and cause sparks. By preventing this sparking from happening, surge protectors do reduce the risk of fire in certain circumstances.

It is important to note, however, that badly maintained or overloaded surge protectors can themselves be fire risks. The best surge protector to prevent fire is one in good working order that is frequently inspected and used appropriately.

pile-of-cables-with-surge-protector-on-top

What Are Tips for Electrical Fire Safety?

The first step in fire and electrical safety is recognizing that electricity will always pose a fire risk and needs to be treated with respect and care. This means prioritizing electrical fire safety as a way to protect staff, property, and business interests.

Here are some electrical safety tips to get you started, broken down into four major categories.

Identify the Biggest Hazards

87% of workplace electrical fires are caused by electrical or mechanical failure, misplaced combustible material, or overloaded equipment. Finding the places these threats are most likely to occur in your workplace is a big step toward mitigating this risk. Some specific hazards to look for include:

Worn or damaged electrical equipment or cords, especially in high use areas or with older equipment.
Overloaded outlets or power strips, especially in temporary setups or lesser used areas where they may not be noticed as quickly.
Combustible and flammable materials near electric currents.
Light fixtures using the wrong wattage bulb.

Inspect These High-Risk Areas

When you have identified areas of particular risk, inspect them regularly as part of workplace safety practices. Fix hazards promptly when they are identified, then develop a schedule for checking on these spaces to notice additional issues as they arise.

For example, an electrical control room has been identified as particularly high risk because staff often leave loose paperwork near banks of electrical outlets. Add the task of looking for this fire risk and removing it as part of the daily rounds for a safety officer.

Install and Maintain Fire Detection and Suppression Systems

Working fire alarms should be in place and regularly tested in all workplaces. Areas of high risk should also be equipped with an effective fire suppression system as well.

Educate Staff on Fire Safety and Evacuation Plans

All staff should receive training on fire safety best practices, as well as how to use any relevant fire suppression system. In our example above where staff were leaving paperwork in the electrical control room, educating staff on why this constitutes a fire hazard can make the workplace a safer environment. It is also important to have an evacuation plan in place and train workers how to follow it.

Which Type of Fire Extinguisher Is Used for Fire on Electrical Equipment?

When looking at how to extinguish an electrical fire, it's important to note what a fire extinguisher is. A fire extinguisher is a portable piece of equipment that sprays water, gas, dry chemical, or foam in order to put out a fire. They are sprayed by a person and generally used on small fires just as they are beginning, when they can be used safely. This contrasts with other fire suppression systems that can cover larger areas and do not require direct human intervention, which we will cover in the next section.

Fire extinguishers can be classified in two ways—by the type and size of fire they will best extinguish and by the type of extinguishing media they contain. Extinguishers are usually labeled clearly with both pieces of information. For electrical fires, the extinguisher should contain non-conductive media, such as dry powder, carbon dioxide, or a clean agent. It should also be labeled with the electrical fire class, which varies by country (Class C in USA, Class E in Australia, Unclassified in EU/India).

Let’s take a closer look at the different types of fire protection systems and why each would or wouldn’t be appropriate for electrical fires and fires around electrical equipment.

Safe Extinguishing Mediums for Electrical Fires

Carbon Dioxide Extinguishers - These utilize only the non-conductive gas CO₂ and leave no residue on equipment after use. There is a human risk of asphyxiation if used in confined spaces.
Dry Powder/Dry Chemical Extinguishers - These extinguish a fire by covering it with non-conductive chemical dusts (often monoammonium phosphate, sodium bicarbonate, or potassium bicarbonate). The powder is potentially harmful if inhaled, requires extensive cleanup, and can damage electrical equipment.
Clean Agent Extinguishers - These suppress fire using inert chemical elements that are non-toxic, do not harm equipment, and require no cleanup. 3M™ Novec™ 1230 Fire Protection Fluid and FM-200™ are the most commonly used today.

Unsafe Extinguishing Media Electrical Fires

Water Spray Extinguishers - Water is conductive, meaning if it is sprayed onto an electrical fire, it can increase the area affected as it conducts the electricity to places it wasn’t already. It will also damage or destroy any sensitive electrical equipment that may be nearby.
Foam/Wet Chemical Extinguishers - Most foam extinguishers are not designed for use on electrical fires and may contain conductive components. They also leave a residue that can damage electrical equipment and requires cleanup.

Workplace Fire Extinguisher Regulations

Because of its high level of importance, fire safety in the workplace regulations exist around providing appropriate fire suppression methods based on workplace hazards. These will vary by country since different regulatory bodies control requirements.

In the United States, the Occupational Safety and Health Administration (OSHA) has the following requirements for portable fire extinguishers:

If a workplace has a specific written fire safety policy that includes staff use of fire extinguishers, work must provide them. Some workplace policies specify that all staff should immediately evacuate without using fire extinguishers. In these cases, extinguishers are generally not required.
Extinguishers should be located no more than 50-75 feet from fire hazard, depending on the type.
Each extinguisher should be visually inspected monthly and physically tested annually.
Staff should be trained on how to use extinguishers when they are hired and annually after that.

How to Put Out an Electrical Fire without an Extinguisher

Fire extinguishers are vital, life-saving pieces of equipment—if they are available and used correctly at the right time. However, they require a person to see a fire while it is still small enough to be put out safely with a portable extinguisher. The extinguisher also must be near enough and visible enough in an emergency situation for a person to be able to quickly access them. Finally, they require that the person using them does so in a way that effectively contains the fire.

Because portable fire extinguishers only work to stop a fire if all these conditions are met, there are many situations where an alternative form of fire suppression is advisable. Other suppression systems include:

Sprinkler systems spray water from multiple points, covering a large area and controlling fire spread. These are not usable for electrical fires because water and electricity don’t mix, and sprinklers will damage or destroy electrical equipment.
Engineered Fire Suppression Systems control fire similarly to sprinklers, except they use a clean agent instead of water. This agent is safe for containing electrical fires, non-toxic to people, does not damage electronics, and does not require cleanup.
High-Pressure CO₂ Systems flood a space with CO₂, stopping a fire without damage to electronics. CO₂ is not always safe to use when people are present due to the risk of asphyxiation, so these systems are usually used for unoccupied spaces. However, it is possible to safely use CO₂ for occupied systems with the proper measures.
Direct Release Systems are designed for small spaces, like an electrical cabinet. They utilize specialized fire detection tubing that runs throughout the space. The tubing will develop a hole when exposed to heat or flame, and the fire suppressant inside the connected canister will spray out of the hole in the tubing and put out the fire.
Indirect Release Systems utilize the same idea and detection tubing as direct release systems but cover a larger space. When fire makes a hole in the tube, this drops the pressure in the system which activates the low-pressure sensitive valve on the canister. This valve then directs the agent through discharge hoses and nozzles that sprays the fire suppressant into the space.
FlexRope Systems are all-in-one systems for detecting and extinguishing fires in very small spaces, like electrical panel boxes. They contain proprietary granules inside a vinyl and fiberglass rope that are activated in a fire event when the temperature reaches 660 degrees. This sets off a chemical reaction that releases a fire-suppressing aerosol and can protect a volume of up to 35 cubic feet.