Class C, D and K Fires
Class C fires involve electrical equipment. This type of fire might be started by old wiring in walls, frayed electrical cords, worn out breaker boxes, or faulty appliances. Electrical fires are most common in both homes and industrial settings. The first thing you should try to do if an electrical fire starts is to disconnect the appliance or item from its power source only if it is safe to do so. If possible, you should try to extinguish the flames using a carbon dioxide or dry powder fire extinguisher. If and when the power source is disconnected, the fire can become a different class of fire, typically Class A.
Class D fires are oftentimes caused by alkali metals such as potassium, magnesium, aluminum, and sodium, as these can ignite when exposed to air or water. Although you're unlikely to face a Class D blaze in your home, it is advised to extinguish these types of fires with a dry powder extinguisher ONLY.
Class K blazes include cooking oils. Because of the high flash point of cooking oils and fats, Class K fires often start when a pan is left unattended for too long on a stove. You should extinguish a Class K fire with a wet chemical extinguisher. These are mandatory in many commercial kitchens, and are a good investment if you do any amount of cooking at home.