Updated 09/2022 by Paul Smith, K5PRS
Generators are a mainstay for prolonged EMCOMM work but they can be dangerous if not handled with respect. Tonight we will cover 14 important safety concerns to keep in mind when working on generators either at a base camp, at home or out in the field.
- Generators produce the common house voltage, 120 Volts AC, with sufficient power to kill. Treat them with the same respect you would if you were working on your home electric system.
- The generator must be grounded with a ground rod driven several feet into the ground. The ground rod should be as close to the generator as possible. A cable capable of carrying the full output load must be securely fastened to the generator frame and the ground rod.
- Use extension cords in good working order and that are the minimum or greater size for the rated power load. Make sure that you use the minimum lengths possible.
- Romex is the cable typically used to wire houses. It is INAPPROPRIATE for use as either ground rod or extension cord cables because it is solid rather than stranded and thus tends to break when flexed repeatedly.
- Do not attempt to defeat the circuit breakers and/or fuses in the generator. The over current protection is there to prevent a fire hazard.
- If the over current protection is repeatedly tripping, there is a problem that needs to be corrected. More often than not the fault is a weak or faulty circuit breaker so carrying a spare is wise.
- If a second fuse blows, you’ll have to dig deeper for the cause which might be an overload. Recalculate the total load. If that’s OK, unplug everything and then plug loads back in one by one until the fault is found. More fuses!
- I strongly recommend the use of Ground Fault Circuit Interrupters (GFCI). GFCIs detect current leakage which can cause serious burns and possible electrocution. GFCIs are required for outlets either outdoors or within 6 feet of water by the National Electric Code (NEC). Again, carrying a spare is wise.
- If using a portable generator to power appliances in a temporary fashion such as a POD or EOC, do not connect the generator directly to house wiring or to an extant power panel to prevent backfeed. Use extension cords instead.
- If configuring a permanent installation, a licensed electrician should be consulted. An improper installation can pose a electrocution hazard or a possible fire. If being used as a backup generator to replace failed electric service, improper installation can pose a serious threat to linemen working on the power lines after an event since the generator will “backfeed”. Backfeed is when the generator energizes the transformer (Pole Pig) servicing your residence and in turn the transformer energizes the main branch circuit.
- NEVER run a generator inside an enclosed space such as a garage. One of the byproducts of combustion is Carbon Monoxide (CO) which is a colorless, odorless and tasteless…but deadly…gas. Note: Nine of the indirect fatalities caused by Rita were due to carbon monoxide poisoning.
- Since generators contain moving parts, do not remove any shielding and do not allow any body part or clothing to get close to any moving parts. These moving parts can cause severe injuries requiring extensive medical care.
- Generators can also pose a burn hazard because they are powered by internal combustion engines. The exhaust muffler is the hottest portion of the generator but any portion of the generator’s engine poses a burn hazard. Caution is advised while working around a hot generator and leather gloves should be used to protect the hands. The gloves will only increase the time between contact and injury so don’t get complacent. Remember that leather gloves are not insulating so they do not protect against electrocution. The gloves linemen use are rubber with leather coverings so the rubber does not get damaged by splinters or other sharp objects.
- Gasoline is extremely flammable and under right circumstances is explosive. One gallon of gasoline, properly vaporized, is as powerful as 70 pounds of dynamite. NEVER smoke or allow open flames and/or sparks around gasoline. Also remember that gasoline vapors are heavier than air and will drift from the leak to a point of ignition and flash back to the leak. This is extremely dangerous. NEVER fill a generator while it is running since the hot muffler under the right conditions can cause a fire. SUGGESTION: A battery sufficient to power operating equipment and a work light should be available to give your generator time to cool and fumes time to dissipate.
- The proper extinguisher for a generator is a Class BC at minimum. A Class B extinguisher is intended to fight liquid based fires such as gasoline while Class C extinguishers are intended to fight electrical fires so a combination is best for working on generators and should ALWAYS be on hand. Water should NEVER be used on a generator fire due to both the electrocution hazard and the fact that gasoline floats on water which will only spread the fire. A Class ABC would cover all fire types.
- Have a plan. As in all anticipated fires, ALWAYS plan several escape routes before starting work on a generator depending on which side you are going to stand even if you think it is sufficiently cool. NEVER, EVER turn your back on a fire. Watch where you’re going but keep an eye on that fire!
That concludes tonight’s training. Are there any questions, comments or suggested additions to this material?
Thanks, this is (callsign) clear to net control.