You put your hand near an outlet, or pull out a plug, and it feels warm. Sometimes that is normal. Sometimes it is the first sign of a connection that is failing inside the box. Heat is the one symptom of a bad connection you can feel before anything else goes wrong, so it is worth taking seriously and worth understanding.
When warm can be normal
- A plug that has been carrying a heavy load. A space heater, hair dryer, toaster oven or window air conditioner draws a lot of current. The plug and cord can feel slightly warm after running for a while. They should not be hot, soft or discolored.
- A dimmer switch. Dimmers make some heat as they work, and a dimmer plate can feel warm when the lights are on. The manufacturer's instructions give the limits for the load it can control; a dimmer feeling hot, rather than warm, is a sign it is overloaded or failing. See LED lights and dimmers.
- A sunny wall. An outlet on a west-facing exterior wall can be warm in the afternoon for the same reason the wall is.
When warm is a warning
- Warm with nothing plugged in. If the outlet has no load and is still warm, heat is coming from inside the box, usually from a loose or failing connection that carries current on to other outlets.
- Hot, not warm. If you cannot comfortably keep your hand on the plate or the plug, stop using it.
- Discoloration. Brown or yellowed plastic around the slots or on the plug.
- A loose fit. Plugs that fall out or wiggle. Worn contacts touch the plug over a smaller area and heat up.
- Smell or sound. A hot plastic or fishy smell, or crackling.
Why a connection heats up
Electricity flowing through a good connection makes almost no heat. Flowing through a poor one, where the wire is loose, corroded or only touching at one point, it makes heat right at that point. The heat loosens the connection further and damages the plastic around it, which makes more heat. That is why a warm outlet tends to get worse, not better, and why many of the dead circuits we repair started as a warm outlet nobody noticed.
In older homes, the push-in connections on the back of inexpensive outlets are a common weak point. In homes with older aluminum branch wiring, connections at outlets and switches deserve extra attention; see aluminum wiring in older Miami homes.
What to do now
- Unplug everything from the warm outlet.
- Turn off its breaker if you can identify it. If you are not sure which one, leave the outlet unused and unplugged.
- Check the neighbors. Feel the outlets on either side. If several are warm or dead, the problem may be one connection feeding the string; see why one bad connection affects several outlets.
- Do not open the box or tighten anything yourself. Heat damage is often worse behind the plate than it looks from the front.
If you see smoke or sparks, or smell burning, follow our guide to burning smells and call 911 if there is any sign of fire.
What the repair involves
We turn the circuit off, open the box, and look at the device and every connection in it. Usually we replace the outlet, cut back any wire that has been heat-damaged, and remake the connections properly with the device's screw terminals or rated connectors. Because the outlet often passes power on to others, we check the rest of the circuit too. If the outlet was carrying a heavy appliance, we look at whether that circuit is the right size for it. Our outlet and GFCI repair page explains the visit.
Preventing it
- Keep space heaters and window units on outlets that are not shared with other heavy loads, and plug them directly into the wall rather than into power strips.
- Replace outlets that no longer grip plugs firmly.
- Do not use adapters to plug several high-draw appliances into one outlet.
- Have warm or discolored outlets looked at when you first notice them, not after they fail.
Questions people ask
Is a warm outlet a fire risk?
It can be. Heat at a connection is one of the ways electrical fires start. A slightly warm plug on a heater is expected. A warm outlet with nothing plugged in, or a hot one, should be taken out of use until it is checked.
Why is only one outlet in the room warm?
Usually because that outlet is the one passing power on to the others, so the full load of the circuit runs through its connections. A weak connection there heats up first. It is also the one most likely to be carrying a heavy appliance.
Can I just replace the outlet myself?
In Florida, electrical work is generally for licensed electrical contractors; our guide to handymen and licensed electricians explains the rules. The bigger risk is replacing the outlet and missing the damaged wire or the second bad connection behind it.
Need it looked at?
KRW Electric (EC13012832) troubleshoots and repairs warm outlets and switches in Pinecrest, Coconut Grove, South Miami and Miami Beach, with same-day service when scheduling permits. Call (305) 359-7312 and tell us what you are seeing. We will ask a few questions, tell you whether it sounds urgent, and give you the earliest time we have. Our before you call checklist covers what to have ready, and what happens on a repair visit explains the rest.
Reviewed by Kyle White, KRW Electric Company LLC — licensed electrical contractor EC13012832.
