Farm electrical systems operate in environments that can be much harder on electrical equipment than a typical home and most commercial buildings. Moisture, dust, corrosion, temperature changes, livestock, rodents, and long operating hours can all affect the reliability of an electrical system.

Agricultural operations also depend on electrical equipment for critical processes such as ventilation, feed systems, grain handling, milking, refrigeration, irrigation, and water systems. When that equipment loses power, the consequences can quickly become more than an inconvenience.

Our Agricultural Electrical Learning Center is designed to answer common questions about farm electrical systems and help farm owners plan for safer, more reliable, and expandable electrical systems.

Farm Electrical Safety

Grounding, Bonding & Stray Voltage

Grounding and bonding are important parts of an agricultural electrical system, particularly in areas occupied by livestock.

Bonding helps keep conductive equipment and surfaces at similar electrical potential so that a person or animal is less likely to become the path between two different voltage potentials.

This becomes especially important in livestock facilities where animals may simultaneously contact metal equipment, water systems, concrete floors, or other conductive surfaces.

What Is Stray Voltage?

Stray voltage generally refers to a small voltage difference that may exist between conductive surfaces that livestock can contact.

If enough voltage is present between two contact points, current can pass through the animal. Depending on the level and circumstances, livestock may react to that current.

Dairy facilities receive particular attention because cows routinely contact grounded or conductive equipment around watering and milking areas.

Finding the source of a stray-voltage concern requires proper testing. The source should not automatically be assumed to be the farm wiring, utility system, grounding system, or any single piece of equipment before measurements are taken.

If stray voltage is suspected, the electrical system can be evaluated and measurements taken to help determine where the voltage is coming from and what corrective action may be appropriate.

Why the Farm Environment Matters

Agricultural buildings can be particularly difficult environments for electrical equipment.

Corrosion & Moisture

Livestock buildings can expose electrical equipment to moisture, dust, manure gases, chemicals, and other corrosive conditions.

Over time, corrosion can damage:

• Electrical enclosures

• Conduit and fittings

• Electrical equipment

• Receptacles

• Electrical motors and motor connections

• Electrical motor starting equipment

• Breakers and electrical distribution equipment

• Grounding and bonding connections

• Other Electrical devices 

Using equipment that is appropriate for the environment and properly installing it can greatly improve service life, but even properly selected equipment should still be periodically inspected.

Corrosion that begins on the outside of an enclosure may eventually affect connections and components inside it.

Regular inspections can help identify deterioration before it leads to equipment failure.

Rodent Damage

Rodents can also create electrical problems on farms.

They may enter electrical equipment, control cabinets, machinery, or other enclosed spaces and damage wiring and insulation.

Keeping electrical enclosures closed, sealing unnecessary openings, and using equipment appropriate for the environment can help reduce the opportunity for rodents to enter.

Where rodent activity is common, wiring and electrical equipment should be included in routine inspections.

Agricultural Equipment & Electrical Systems

Farm electrical systems often supply equipment that operates differently than other building electrical loads.

Motors may start and stop frequently, equipment may run for long periods during harvest, and several large loads may need to operate at the same time.

When planning an agricultural electrical system, it is important to consider both the equipment being installed today and how the operation may change in the future.

Grain Handling & Drying

Grain systems can include significant electrical loads such as:

• Bin fans

• Grain dryers

• Augers and conveyors

• Bucket elevators

• Aeration equipment

• Control / monitoring systems

Adding equipment without considering the capacity of the existing electrical system can eventually create problems with the service, feeders, distribution equipment, or voltage available to the equipment.

Planning the electrical system around both current and future grain-handling needs can make expansion much easier.

Irrigation Systems

Irrigation systems may require increased electrical capacity depending on pump size, controls, and the type of system being operated.

Electrical planning should consider motor starting requirements, available service capacity, controls, and the distance between the electrical source and equipment. The two biggest factors being the distance between the source and equipment, as well as the starting capacity of electric motors. 

Variable Frequency Drives

Variable frequency drives, commonly called VFDs, are frequently used to control electric motors.

A VFD can provide better control over motor speed and operation and can be useful on equipment such as pumps, fans, ventilation systems, and processing equipment.

Like other electronic equipment, VFDs need to be properly installed and kept clean and adequately cooled. Dust, blocked cooling paths, failed fans, heat, and environmental conditions can significantly shorten the life of electronic controls.

Backup Power for Farms

For many agricultural operations, losing electrical power can quickly become a serious problem.

Ventilation, water, heating equipment, refrigeration, feeding systems, milking equipment, grain systems, and other critical loads may need to continue operating during an outage.

The right backup power system depends on what equipment needs to operate and how the farm is set up.

Automatic Standby Generators

A permanently installed generator with automatic transfer equipment can detect a utility outage and automatically supply designated farm loads.

These systems may be powered by natural gas, propane, or diesel depending on the size and application.

Automatic systems can be particularly useful where equipment needs to continue operating even when nobody is available to manually connect or start a generator.

PTO Generators

A PTO generator can be a practical option for some agricultural operations because the farm already owns and maintains the tractor that provides the power source.

PTO systems generally require more operator involvement than an automatic standby generator, but they can provide substantial backup capacity without maintaining a separate engine solely for emergency generation.

Regardless of generator type, the system needs to be properly sized for the loads it will operate and properly connected to prevent the generator from energizing the utility system.

Visit our Generator Learning Center to learn more about generator sizing, transfer equipment, fuel options, and choosing between automatic and manually operated backup power systems.

Preventive Electrical Maintenance

Electrical maintenance can be especially valuable on farms because of the conditions electrical equipment operates in.

A maintenance program may include:

• Visual inspection of electrical equipment

• Checking for corrosion and moisture damage

• Cleaning equipment where appropriate

• Checking motors and motor controls

• Inspecting disconnects and electrical distribution equipment

• Looking for damaged wiring

• Checking grounding and bonding connections

• Thermal imaging inspections

• Identifying equipment that may need repair or replacement

The goal is not simply to find equipment that has already failed. It is to identify developing problems while there is still time to plan and schedule a repair.

Thermal Imaging on Agricultural Electrical Equipment

Thermal imaging can be incorporated into an agricultural electrical inspection to help identify equipment operating at abnormal temperatures.

Possible areas to inspect include:

• Electrical panels

• Disconnects

• Motor starters and contactors

• Motor control equipment

• Variable frequency drives

• Large electrical connections

• Motors

• Other heavily loaded electrical equipment

• Specialty electrical equipment

Thermal imaging is particularly useful when equipment can be inspected while operating under normal load.

Over time, documented inspections can also help establish what is normal for a particular piece of equipment and make changes easier to recognize.

Visit our Thermal Imaging Learning Center to learn more about thermal surveys and preventive electrical maintenance.

Planning for Future Farm Electrical Needs

Farm operations rarely stay exactly the same.

A new grain bin, machine shed, livestock building, irrigation system, larger dryer, additional ventilation, or new piece of machinery can significantly change the electrical needs of an operation.

Building a New Machine Shed?

Before choosing electrical equipment, it is worth thinking about what the building may eventually be used for.

Future equipment may include:

• Welders / Plasma torches 

• Metal Fabrication equipment

• Air compressors

• Vehicle or equipment lifts

• Large power tools and equipment

• Heating equipment

• Grain or farm equipment

• Additional flood or task lighting

• Communication or security equipment

Planning ahead does not mean everything has to be installed immediately.

Sometimes it may make sense to install larger distribution equipment, leave space for additional circuits, or install spare conduit while construction is underway.

A relatively small amount of planning during construction can make future electrical additions considerably easier.

Planning for Farm Expansion

The same idea applies throughout the farm.

When upgrading an electrical service or distribution system, consider what the operation may look like several years from now.

Providing room for future electrical loads or installing a spare pathway to an area that may eventually be expanded can prevent significant rework later.

Our goal is to help build an electrical system that fits the operation today without unnecessarily limiting what the farm can do tomorrow.

Have an Agricultural Electrical Question?

Farm electrical systems can be complicated because every operation is different.

If you are adding equipment, building a new facility, troubleshooting an electrical problem, considering backup power, or trying to improve the reliability of your existing system, we can help evaluate the electrical requirements and discuss your options.

As we receive more questions from farmers and agricultural businesses, we will continue adding them to this Learning Center so it becomes a useful resource for agricultural electrical maintenance, safety, and planning.