Electrical fires & Fire Extinguishers

Electrical fires and Fire Extinguishers

But First a bit about Portable Fire Extinguishers…Basically Fire extinguishers are devices that release chemicals and/or water to put out a fire. They keep small fires from spreading, assist in fighting fires but are only first to the incident appliances until the fire department arrives. Fire extinguishers and on site Fire hoses are designed to provide the user with an appliance to attend a small fire during its initial stage. When deciding to attack a fire, always designate another person to raise the alarm and obtain a back-up fire extinguisher. Portable fire extinguishers should be provided in all buildings.

Types of fire extinguishers and their application

There are basically 5  types of portable fire extinguishers used here  in Australia. They are Water, Foam, Dry Powder, Wet Chemical and Carbon Dioxide. Each type of extinguisher may be rated for one or more classes of fire. In some cases, particular extinguishers are not only considered ineffective against certain classes of fire, they can be dangerous in those circumstances. The Classes of fire are:

CLASS A Paper, Wood, Cardboard

CLASS B Solvents, Paint, Petroleum, Ethanol/methanol

CLASS E Electrical fires(this is the one we are going to concentrate on in this article)

CLASS F Cooking oils and fats


To use the extinguisher, you pull out the safety pin (this metal safety pin prevents the operating lever from closing accidentally) and depress the operating lever. The lever pushes on an actuating rod, which presses the spring-mounted valve down to open up the passage to the nozzle. The bottom of the actuating rod has a sharp point, which pierces the gas cylinder release valve. The proper way to use the extinguisher is to aim it directly at the fuel, rather than the flames themselves, and move the stream with a sweeping motion.

Using an extiguisher

Of the 5 extinguishers types 2 are suitable for Electrical fires they Dry Powder and Carbon Dioxide

Dry Powder

ABE powder consists of mono ammonium phosphate and/or ammonium phosphate. It is effective on Class A: B & E Fires .As well as suppressing the flame in the air, it also melts at a low temperature to form a layer of slag which excludes oxygen from the fuel. For this reason it is effective against class A fires unlike a Rating B:E only extinguisher. ABE powder is the best agent for fires involving multiple classes.

Carbon dioxide

Carbon dioxide is especially effective on electrical fires, Class E Fires, as being a gas; it does not leave any residues which might further harm the damaged equipment. Carbon dioxide (CO2) also works on Classes B and C Fires by displacing the less dense oxygen. This can be problematic in enclosed occupied spaces as we need oxygen too! Although carbon dioxide is exhaled in our own breath, in the high concentrations required to extinguish deep seated fires it is one of the most toxic extinguishing agents used. (Carbon dioxide can also be used on Class A Fires when it is important to avoid water damage, but in this application the gas concentration must usually be maintained longer than is possible with a hand-held extinguisher.)

So as you can see Both of these extinguisher are suitable for Electrical fires but it depends on whether your fighting a fire in a confined space which would make using the Carbon Dioxide Extinguisher out of the question!

Tested & True ~ test & tag  Lonsdale also does fire Extinguisher and smoke Alarm testing to National Standards.. Also we Test and Tag electrical items and we use the very latest in Portable Appliance Testing…The STC ProLogger 2 it can perform RCD testing, Earth Leakage Detection and Run Testing all in one neat piece of equipment. On top this all our Technicians are Trained to National Standard UEENEEP008 in test & tag operations by Intertag in Sydney NSW, all our Equipment is in good repair and in Calibration. Most of all we pride ourselves on our Knowledge of OH&S legislation and the current Australian Standards ensuring that you get Quality Service at a competitive price.

Article By Peter Hill… Tested & True ~ test & tag, Lonsdale, South Australia, Contact 0407605568 www.testedandtrue.com.au


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