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How Long Can a 220 Volt Extension Cord Be? – Answered

Written by Edwin Jones / Fact checked by Andrew Wright

how long can a 220 volt extension cord be

Extension cords can provide power to appliances when outlets are too far away. They can be your temporary electrical connectors while permanent ones are being installed. Even 220 volt appliances might need an extension cord at one point.

But how long can a 220 volt extension cord be? Is it safe to use? And what affects the choices for a 220v extension cord?

In short, you should limit the length to 100ft, but even at this range, there’s a need to account for voltage drops. Learn the details below.

Voltage Drop

220v-extension-cord

The biggest concern about the length of extension cords is probably the voltage drop. While voltage drop does not inherently damage the extension cord, it decreases the performances of appliances plugged into it or might even harm them.

In order for current to flow through a certain length of wire, it needs a push, or pressure across the wire. This “pressure” is known as voltage, and in a 220V outlet, this “pressure” can range from 220V to 250V. When an appliance is directly plugged into the outlet, it more or less experiences 220V and can operate normally.

However, while wires are very good conductors of electricity, they innately have resistance. Resistance is a measure of how a material or equipment blocks current flow (for AC circuits, impedance is used instead of resistance).

It causes the “pressure” (aka the voltage) at the end of the wire to drop, reducing the current that would flow to the appliance.

This occurrence is known as a voltage drop, and wires can affect voltage drops in several ways:

  • The type of material

Some materials can cause a greater voltage drop than others. Aluminum as a conductor can cause a greater voltage drop than copper. This makes copper a very good choice for wires.

  • The length of the wire

Increasing the length of the wire means adding more material, hence more resistance. Thus, longer wires create greater voltage drops.

  • The thickness of the wire

Increasing the thickness of the wire allows more current to pass through. Thus, the thicker the wire, the lower the voltage drop.

Looking at these factors, a longer 220 volt power cord will need thicker wires to prevent a significant voltage drop.

The National Electric Code generally recommends a voltage drop of 3% at the farthest outlet of the branch circuit, and 5% for the entire feeder and branch circuit (even lower for sensitive electrical equipment). Check the wiring diagram to identify the farthest outlet.

If the voltage drop is significant, appliances may not receive their normal operating voltage.

For instance, heaters may not reach their peak heating output, which leads to slower heating times. Motors may take longer to start a load, and their stator windings may overheat. Moreover, light bulbs might not get bright enough.

Online wire size calculator and voltage drop calculators are available. These tools can help determine the appropriate extension cord for the appliance.

Maximum Extension Cord Length

220-volt-power-cord

Generally, the longest extension cord in a workplace should be 100ft, according to the Occupational Safety and Health Administration, or OSHA.

Having extension cords longer than 100 ft or multiple extension cords connected to each other is considered a safety violation. If the cable distance exceeds 100 feet, it should have its own temporary power distribution box.

Different extension cord lengths are available in stores.

For instance, Harbor Freight offers extension cords up to 100 ft for 15 amp, 120 volt outlets, and shorter extension cords for 30 amp current.

Amazon also has 220 volt 50 amp extension cord up to 100ft for electric vehicle charging. Take note that as extension cords get longer and have higher ampacity ratings, the costs also increase.

How to Choose the Right Wire Gauge for a 220v Extension Cord?

The table below summarizes the minimum wire thickness at a certain ampacity, voltage and extension cord length. The handy table accounts for 3% maximum voltage drop along the branch circuit where the extension cord will be plugged.

Minimum wire thickness (in AWG)
Ampacity (A) Voltage (V) 25 feet 50 feet 75 feet 100 feet
15 120 12 12 10 8
20 120 10 10 8 8
30 120/240 8 8 8 6
40 240 6 6 6 6
50 240 6 6 6 6

Frequently Asked Questions

220-amp-extension-cord

What is the maximum length for a 30 amp extension cord?

A 30 amp extension cord can reach 100ft, and you can confirm this by going on Amazon. However, such a cable can set you back by as much as $200.

Is there a limit to the length of an extension cord?

OSHA mentions that generally, the maximum length of extension cords in workplaces is 100ft. Check their recommendations to ensure compliance.

Does the length of an extension cord affect the power?

Yes. The longer the extension cord, the greater the voltage drop, thus the lower the current draw and the appliance’s output power.

Can I use a 110V extension cord with 220v?

In theory, you can use a 110v extension cord with a 220V outlet as long as the ampacity of the wire is not exceeded. However, a 110V extension cord may have a different prong compared with a 220V one, so you should know how to wire the former to a 220V outlet.

Also, the insulation may be less for 110V cords than 220V cords.

Can I use a 240V extension cord for a 220V outlet?

Yes. Generally, 220V and 250V service are interchangeable, so using a 240V extension cord for a 220v outlet is fine.

Is there such a thing as a 220 amp extension cord?

You may be referring to a 220V extension cord. Amps for current and volts for voltage are different quantities and should not be interchanged. A 220 amp extension cord is dangerous if it does exist.

Conclusion

Extension cords can reach up to 100ft. But remember that longer extension cords will need thicker wires and will be pricier, so it’s best to have a fixed distribution box if you want to distribute electricity over long distances.

Hopefully, you now know how long can a 220 volt extension cord be. Always prioritize safety when sizing your cable instead of convenience.

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