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Extension Cord Getting Hot? When It's Normal and When to Replace It

Warm under load can be normal. Hot, soft or smelly is not. Unplug it, match the cord to the load, and use a 12-gauge cord for heavy draws.

By Jamilur Rahman Updated November 5, 2026 · 7 min read

Time
15 min
Cost
$20-$50
Difficulty
Easy
A coiled extension cord on a workshop floor with its plug end slightly darkened
In this guide
  1. Quick answer
  2. Free vs. permanent fix
  3. What you'll need
  4. Why it happens
  5. Try this first (free)
  6. When free fixes aren't enough
  7. Buy the fix
  8. What the gauge numbers mean
  9. When to stop and call an electrician
  10. What to skip
  11. FAQ
  12. Related problems

Quick answer

A cord that feels slightly warm under a steady load can be normal. A cord that is hot to the touch, has a soft or discolored plug, smells like burning or trips the breaker is not safe. Unplug it, uncoil it and check that its amp rating is above what you have plugged in. If the load is heavy, switch to a 12-gauge cord, because thicker wire stays cooler.

Free fix vs. permanent fix

Free fix · 10 minutes

Unplug, uncoil and match the cord to the load

  • Unplug it and let it cool
  • Uncoil the whole length and keep it off rugs
  • Add up the watts of everything plugged in
  • Plug high-draw devices straight into the wall

How long it lasts: It fixes coiled or overloaded cords for good. It cannot fix a thin or damaged cord.

Most readers choose Permanent fix
12-gauge heavy-duty extension cord (illustration)
Illustration

A 12-gauge heavy-duty extension cord

A cord heats up because its wire is too thin for the load or too long for it. A 12-gauge cord has thicker wire, so it carries heavy loads cooler. It fixes the cause instead of just hiding the heat.

What to get: 12-gauge heavy-duty extension cord

How long it lasts: Years. Thicker wire carries more current with less heat.

Check price on Amazon

As an Amazon Associate I earn from qualifying purchases.

What you'll need

  • Appliance labels and a calculator

    Read the watts or amps on each device and add them up

    You have it

  • A free wall outlet

    High-draw devices go straight in, with no cord

    You have it
  • Our pick
    12-gauge heavy-duty extension cord (illustration)
    Illustration

    12-gauge heavy-duty extension cord

    Choose the shortest length that reaches

    Check price
  • 14-gauge extension cord (illustration)
    Illustration

    14-gauge extension cord

    For lighter loads over short runs

    Check price

Why it happens

1

A cord too thin for the load

Thin cords carry less current. When a device draws more than the cord is made for, the wire heats up. A lower gauge number means thicker wire: 16 is thin, 12 is heavy-duty.

2

A long cord with a big load

More wire means more resistance, so more heat. A 100-foot cord runs hotter than a 10-foot cord carrying the same load.

3

A coiled or covered cord

A coiled cord cannot shed heat. Rugs, boxes and furniture trap it the same way.

4

Damage or a loose plug

A nicked cord, a bent plug blade or a loose outlet creates resistance at one spot, and that spot heats up. This is more dangerous than an evenly warm cord.

Try this first (free)

Do these in order, starting with the simplest.

  1. Unplug it and let it cool

    Pull the plug, not the cord. After a few minutes, feel the cord, the plug and the wall outlet. Melted plastic, scorch marks or a burning smell mean the cord goes in the trash and the outlet needs an electrician.

  2. Uncoil the whole length

    Lay the cord straight or in a loose zigzag, off rugs and out from under furniture. Never run it coiled or under a rug.

  3. Check the load

    Tool used: Appliance labels and a calculator

    Read the watts or amps on each device's label. In the US, watts divided by 120 gives amps. Compare the total with the amp rating printed on the cord or its plug.

  4. Plug high-draw devices into the wall

    Tool used: A free wall outlet

    Space heaters, portable air conditioners, microwaves and hair dryers should go straight into the wall. They draw more than most extension cords are made for.

  5. Switch to a 12-gauge cord for heavy loads

    Tool used: 12-gauge heavy-duty extension cord

    If you must use a cord for a power tool or a heavy appliance, choose a 12-gauge cord in the shortest length that reaches. Check for a safety mark and a rating that covers your load.

    12-gauge heavy-duty extension cord (illustration)
    Illustration

    Tool for this step

    12-gauge heavy-duty extension cord · Choose the shortest length that reaches

    Check price on Amazon

When free fixes aren't enough

Replace the cord if the plug or cord is discolored, soft, cracked or stiff, if a blade is bent, if the cord feels hot rather than just warm, or if it smells like burning. Tape does not fix any of that. If the outlet itself is hot, or the plug sparks or buzzes, stop using it and call an electrician. The same goes for a breaker that trips when you plug the cord in. A new 12-gauge cord only helps when the cord was the weak point. It cannot fix a bad outlet or an overloaded circuit.

Buy the fix

Still stuck after the free fixes? These are the products we would look at.

Our picks compared
PickProductFixesWho it's forBuy
Best pick
12-gauge heavy-duty extension cord (illustration)
Illustration
12-gauge heavy-duty extension cord
a cord that overheats under a heavy load Anyone running power tools, a shop vacuum or a long run to a medium or heavy load. Check price
Budget pick
14-gauge extension cord, short length (illustration)
Illustration
14-gauge extension cord, short length
a thin 16-gauge cord on a medium load People who run a computer, monitor, fan or vacuum over a short run. Check price
Upgrade pick
10-gauge extension cord (illustration)
Illustration
10-gauge extension cord
long, heavy runs where even a 12-gauge cord runs warm Workshop users and contractors with long runs and big loads. Check price
Best pick
12-gauge heavy-duty extension cord (illustration)
Illustration

12-gauge heavy-duty extension cord

Fixes: a cord that overheats under a heavy load

Look for: 12 AWG printed on the cord; A grounded three-prong plug and a safety mark such as UL or ETL; An outdoor rating, if you will use it outside; The shortest length that reaches your outlet.

Who it's for
Anyone running power tools, a shop vacuum or a long run to a medium or heavy load.
Honest downside
You only run a lamp or a charger. A lighter cord is fine, and a 12-gauge cord is stiff and heavy.
Check price on Amazon
Budget pick
14-gauge extension cord, short length (illustration)
Illustration

14-gauge extension cord, short length

Fixes: a thin 16-gauge cord on a medium load

Look for: 14 AWG printed on the cord; A short length, 10 to 25 feet; A grounded plug and a safety mark.

Who it's for
People who run a computer, monitor, fan or vacuum over a short run.
Honest downside
You plug in a heater, air conditioner or large power tool. Use a 12-gauge cord or the wall outlet.
Check price on Amazon
Upgrade pick
10-gauge extension cord (illustration)
Illustration

10-gauge extension cord

Fixes: long, heavy runs where even a 12-gauge cord runs warm

Look for: 10 AWG printed on the cord; A flexible outdoor-rated jacket; A rating that covers your heaviest tool.

Who it's for
Workshop users and contractors with long runs and big loads.
Honest downside
The run is short and the load is small. It is heavy and stiff.
Check price on Amazon

As an Amazon Associate I earn from qualifying purchases. We don't show prices because they change, so use the button to see today's price.

How we picked: How we picked: this page is based on electrical safety guidance on extension cord use, wire gauge and amp rating charts, and the problems and fixes owners report in reviews. We do not test products by hand.

What the gauge numbers mean

  • 16 gauge: light loads, such as a lamp or a phone charger.
  • 14 gauge: medium loads, such as a computer, fan or vacuum.
  • 12 gauge: heavy loads, such as power tools.
  • 10 gauge: long runs with heavy loads.

A lower number is thicker wire. Check the amp rating printed on the cord too.

When to stop and call an electrician

Stop using the cord and unplug it if you see scorch marks, melted plastic or a discolored plug, or if you smell burning. Call an electrician if the wall outlet is hot, sparks, buzzes or loosely grips the plug, or if the breaker trips when you plug in. These are problems in the wiring, not the cord.

What to skip

Thin power strips as cords, and tape repairs

A power strip with a thin cord is not made for heaters or tools, and plugging strips into each other is a classic cause of heat. Electrical tape over a damaged cord hides the damage and does not restore the insulation. Replace the cord.

Frequently asked questions

Why is my extension cord hot?
Current is heating the wire. That happens when the cord is too thin or too long for the load, is coiled up, or has damage. Unplug it, check the load, and replace the cord if it is discolored or hot to the touch.
Is it normal for an extension cord to get warm?
A little warmth under a steady load is normal. Hot, soft or smelly is not. If you cannot comfortably keep your hand on it, stop using it.
What is the largest gauge extension cord?
Gauge works backward: a lower number is thicker wire. 16 is thin, 14 is medium, 12 is heavy-duty and 10 is among the thickest cords sold for home use. A 12-gauge cord is enough for most homes. Save 10-gauge for long, heavy runs.
Can I use an extension cord for a space heater?
Plug it straight into the wall. Most heater makers say to avoid cords. If the manual allows one, use a short, heavy-duty cord rated for the heater's load.
Can I plug two extension cords together?
Avoid it. Joining cords adds length and resistance, and the joint can heat up. Buy one cord that reaches.

As an Amazon Associate I earn from qualifying purchases. Affiliate disclosure

12-gauge heavy-duty extension cord (illustration)
Illustration

Our pick: 12-gauge heavy-duty extension cord

Check price