Generator Safety
Information
For
Your Farm & Home

Washington Electric Cooperative, Inc.
A Touchstone Energy Cooperative

Table of Contents

Policy
Generator Information
Generator Sizing Information
Connecting the generator to your home
Safety

Warning

Follow all National Electrical Code Standards

Failure to do so may be hazardous or even deadly

Policy

Washington Electric Cooperative, Inc. establishes that where the consumer has emergency generating equipment installed, the consumer shall install and maintain Cooperative approved double-throw switching and protective devices so that it will be impossible for the consumer to operate his generating equipment in parallel with the Cooperative's system. All consumer's equipment shall be installed beyond the metering point and on/in the consumer's pole/structure. The generating equipment, wiring and switching installation shall comply with the National Electric Code.

Due to the possibility of a fatal accident occurring, the Cooperative reserves the right to discontinue its service without notice if the consumer's installation does not at all times comply with the provisions and requirements of the Cooperatives generator policy.

The only time you do not need a transfer switch is when you are plugging the electrical equipment directly into the generator itself and the generator is not connected to your house wiring in any way.

Because the transfer switch can mean the difference between life and death for a lineman working on the power lines (backfeeding), only a qualified licensed electrician should wire the transfer switch for a consumer.

Generator Information

Types of Standby Generators

Engine-Driven Generators - the generator and engine come as a set, designed and sized to work together. Available in a wide range of sizes - from small portable units to large diesel units which are permanently anchored and wired to the electrical system. The smaller units are typically 5 to 15 kW capacity. The larger permanently installed generators will typically have battery-powered starters and can be completely automatic. It is suggested that a generator be started (can be automatic start) monthly or weekly to insure the unit is functional and ready for emergency use. These smaller generators are readily available in most hardware, department, discount, or farm supply stores. The most sought after features on these units are the low-oil safety switch, battery start, fuel gage, main line circuit breaker and the variable speed engine operation. The most critical issue is sizing the generator to maximum or startup load (presented in a later chart). Your choice of fuel supply must be determined prior to purchasing the unit since generators can operate by using one of the following fuels: gasoline, propane, natural gas or diesel fuel.

Tractor-Driven Generators - this typically larger generator is power-take-off driven using a farm tractor as the mechanical energy source to turn the generator. The advantages to this system will be a lower initial cost, less maintenance by not having an additional engine to service and the opportunity to tow a larger generator to different locations. If you are considering a tractor-driven unit, evaluate the PTO capacity of the tractors you have and be sure to have sufficient size to match the generator and anticipated load requirements. The horsepower rating of the tractor should be twice the kilowatt capacity of the generator. For example a 60 hp tractor is the minimum recommended for a 30 kW generator.

Manual Start Generator Sizing

1. Itemize the essential loads with wattage, horsepower, and amperes.
2. For motors, determine all starting and running kVA values.
3. Sum the wattage of all essential electric heating and lighting loads to determine a base kVA value.
4. Add the base kVA value, the starting kVA of the largest motor (No. 1) and obtain a total.
5. Add the running kVA of motor No. 1 to the starting kVA of No. 2 plus the base value, and obtain the total.
6. Add the running watts of No. 1 and 2 to the starting watts of No. 3 plus the base wattage, obtain the total.
7. Continue calculating until all loads to operate at the same time have been considered. You need a generator with a starting capacity equal to the maximum kVA required.

* The fixture draws more power than the lamp wattage because of the ballast.

Rule-of-Thumb Examples for Generator Sizing

The Double-Throw Switch, a "must" for generator operation

Double-throw means that the operator can place or "throw" the switch into two different positions. One position feeds power from the utility system to the load while the other position feeds power from the standby generator to the load. This switch does not allow for a backfeeding to occur; backfeeding occurs when electricity travels from the generator back through the transformer and onto the power lines where linemen maybe working. The transformer increases house voltage back up to 7,200 volts on the power lines during back feeding. This switch will also prevent damage to a consumer's generator when the utility re-energizes its system during an outage.

Typically the transfer switch is located between the utility meter and loads to be served. It should be within 25 feet or less of the generating unit for convenience and safety. If the location of critical loads are scattered among several outbuildings, the central meter pole may be the best location for both the transfer switch and the generator.

Typical Double-Pole, Double-Throw Transfer Switch

Safety

Think Safety First!

~ Don't use a generator indoors. Burning fuel produces carbon monoxide, which is deadly. Operate the generator in a well-ventilated area.

~ Be sure you have a properly installed transfer switch before you hookup your generator.

~ Check your wiring to be sure it's in good condition. If you have damaged wiring, be sure all repairs are done prior to attaching the generator to your load. Comply with the National Electric Code standards and use only a qualified electrician.

~ Voltage drop may occur if an extension cord connected to the appliance is too long, or the wires are too small. The longer the cord, the bigger the wires need to be. If the extension cord becomes very warm during use, it is inadequate and poses a fire danger.

~ Many engine parts are very hot during operation, and severe burns may result if touched. Keep children away from generators at all times.

~ Electric motors require extra power on startup. Be sure to calculate your load and startup requirements before your generator is attached to the double-throw switch. Don't overload the generator.

~ Never fuel an electric generator while the generator is running.

~ Check the oil level in the engine each time you use or refuel the generator.

~ Do not remove or tamper with safety devices. They are there to protect you and your property.

~ To keep your generator ready for emergency use, operate a generator of an engine powered unit once per month and operate the generator of a tractor driven unit at least once every three months.

~ Keep record of hours used, lubrication, change of oil, filters, according to equipment specifications.

~ Seek the advice of a certified electrician if you are in doubt of any portion of your electrical system.