What Size Generator Do You Need to Run an Electric Fence?
By the Generator Size Calculator Team · Updated · 5 min read
Quick answer: Honda lists an electric fence (25 miles) at 250 running and 250 starting watts. A 1,000-watt inverter runs it with room to spare. Add a 1,000-watt stock tank de-icer and a few lights and a 2,500-watt generator covers the lot. Many fence energizers are far smaller, so check your unit's label.
Electric fence watts
| Equipment | Running watts | Starting watts |
|---|---|---|
| Electric fence (25 miles) | 250 | 250 |
| Stock tank de-icer | 1,000 | 1,000 |
| Lights | As printed on the bulb | As printed on the bulb |
These are Honda's typical figures, and a fence energizer has no big start-up surge. Small energizers for a few acres draw far less than 250 watts, so check the label or measure it.
Which generator size to choose
| Setup | Running load | Generator |
|---|---|---|
| Fence alone | 250 W | 1,000 W inverter |
| Fence and a few lights | about 350 W | 1,000 W inverter |
| Fence, stock tank de-icer and lights | 1,350 W | 2,500 W |
Sizes keep the running load under 80% of the rating. A 1,000-watt inverter's 80% mark is 800 watts, which covers the fence and some lights but not a de-icer. For the de-icer on its own see what size generator runs a stock tank de-icer.
Example: fence, de-icer and lights
| Load | Running watts |
|---|---|
| Electric fence (25 miles) | 250 |
| Stock tank de-icer | 1,000 |
| Barn lights | 100 |
| Running total | 1,350 |
With no start-up surge, the peak equals the running total. A 2,500-watt generator's 80% mark is 2,000 watts, so 1,350 fits easily. The barn lights are an example value.
List the fence, tank heaters and lights.
Tips for livestock outages
- Plan the fuel. See how long a generator runs on a tank of gas.
- Use heavy outdoor cords for any run to a barn. See the extension cord calculator.
- Consider a battery fence. Solar and battery energizers need no generator.
Run the generator outdoors, at least 20 feet from doors, windows and vents. Never in a garage, barn or shed, even with the door open. Keep it out of barns and animal shelters. See how far a generator should be from your house.
Frequently asked questions
How many watts does an electric fence use?
Honda lists a 25-mile electric fence at about 250 watts. Small energizers use much less, so check yours.
Can a 1000-watt generator run an electric fence?
Yes. 250 watts is well under the 800-watt 80% mark of a 1,000-watt inverter.
Does an electric fence have a starting surge?
Honda lists the same starting and running watts, so no extra surge.
What size generator runs a fence and a de-icer?
About 2,500 watts for a fence, a 1,000-watt de-icer and some lights.
Do I need a generator for a fence at all?
Not always. Battery and solar energizers run without mains power.
Related calculators
Sources: Running and starting watts from the Honda generator wattage guide (electric fence, stock tank de-icer). Generator sizes apply the 80% running rule. The barn lights in the example are an assumed value.