December 12, 2002

Is Your Standby Generator Standing By?

Blink, blink. The lights go off, come back dimly and then stay off. It is completely dark from horizon to horizon – the power is off! As you head for the machine shed to start the standby generator, you wonder how long the house will stay warm and when the pipes will begin to freeze. Your biggest concern is whether the generator will start.

George Maher, North Dakota State University Extension Service safety specialist, paints this scene to stress the importance of making certain that your standby generator receives necessary maintenance before the power goes off.

Maher notes that several factors influence the generator’s ability to start, do its job and operate safely. The power for a standby generator usually comes from a built-in engine or through the PTO shaft of a farm tractor. Either type must be kept in operable condition, requiring fresh fuel, a strong battery, good electrical connections, clean filters, and maintenance on the liquid cooling system. It is important to always follow the manufacturer’s instructions on engine maintenance.

"Fuel for a standby generator, gasoline or diesel, should be fresh at the start of the season," Maher says. "Transfer the old fuel to a pickup or tractor that will use it up soon, but don’t put it back in the bulk fuel tank. Keep the generator fuel tank filled completely during the winter months to prevent condensation moisture that will freeze and plug the fuel line. Also, add a fuel stabilizer to keep the stored fuel in good condition."

The liquid cooling system needs seasonal maintenance, just as vehicles do. Test the antifreeze and replace it according to the manufacturer’s instructions. A failed cooling system during a power failure can be extremely expensive.

"When the generator is tractor/PTO powered, the first concern is; will the tractor start?" Maher says. "The tractor dedicated for the generator must start easily and be in top operating condition so it is dependable."

The next step is to make sure that there is access to the generator. If seasonally-used machinery is parked in front of it, access can be almost impossible. In the winter months, this can be a big problem.

Another aspect of access is the availability of a correct PTO shaft. "It is not good planning to use the generator’s PTO shaft on other equipment during the year," Maher says. "Keep a PTO shaft just for the generator and make sure it is properly shielded."

If the generator is installed for indoor operation, safety requirements must be met:

• Exhaust gases should be vented directly outdoors.
• A metal grommet or flange should insulate the building wall from the hot exhaust pipe where it passes through.
• Fresh air should be available for engine consumption and cooling.
• Safe storage should be provided for the fuel tank so vapors are not a hazard.
• Winter-grade fuel should be available and safely stored.

There are electrical safety considerations with a standby generator also. The transfer switch that disconnects the farm from the power company’s power line and connects the farm to the generator must be a double-throw transfer switch. This type of switch prevents the generator from feeding electricity back to the power line, protecting the linemen who may be working to restore your service. It also keeps the generator from overloading by trying to supply electricity to the whole neighborhood.

Maher notes that it is important to make sure that all conductors or wires are of sufficient capacity because an overload can cause fires. He also points out that it is necessary to respect the limited capacity of the generator. If the generator cannot provide voltage within 10 percent of what is needed, some loads must be shut off. Increasing the speed of the generator past its rated limit will damage the unit.

"Consult your local electric power supplier if there are questions about the safety and suitability of your standby generator and its installation," Maher says.

Additional information can be found under Publications on the NDSU Extension Agricultural and BioSystems Engineering Web site and is available from local County Extension Agents or from the NDSU Extension Agricultural and BioSystems Engineering Department at (701) 231-7236.

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Source: George Maher, (701) 231-8288, gmaher@ndsuext.nodak.edu
Writer: Teresa Oe, (701) 231-8371, teresa.oe@ndsu.nodak.edu
Editor: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu

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