Learn · Electrical

Electrical, in plain English.

Panels, breakers, outlets, EV chargers and staying safe with electricity.

The lingo (17)Guides and reading (8)Articles (8)From the Pros (0)Questions (0)Ask the Pros

The lingo.

AFCI
Arc-fault circuit interrupter, a breaker that detects the sparking of a damaged wire or loose connection and shuts the circuit off. Required on most living-area circuits in new work.
Aluminum wiring
Branch wiring used in some homes built from about 1965 to 1973. It loosens and overheats at connections; fixes include approved connectors or rewiring, and insurers ask about it.
Amp, volt, watt
Amps are current, volts are pressure, watts are power (volts times amps). A 20 amp, 120 volt circuit can carry about 2,400 watts, and code allows a continuous load of 80 percent of that.
Breaker
The switch that trips to cut a circuit when it draws too much current. A breaker that trips repeatedly is protecting you from something; do not replace it with a bigger one.
Conduit
Metal or plastic pipe that protects wires, used outdoors, in garages and wherever cable would be exposed to damage.
Dedicated circuit
A circuit serving one appliance only: range, dryer, microwave, dishwasher, EV charger, HVAC. Sharing them is how breakers trip and wires overheat.
EV charger (Level 2)
A 240 volt charger that adds 20 to 40 miles of range per hour. Needs a dedicated 40 to 60 amp circuit; a load calculation decides whether the panel can handle it.
GFCI
Ground-fault circuit interrupter, the outlet or breaker with test and reset buttons. Required near water: kitchens, baths, garages, outdoors. It cuts power in milliseconds when current leaks to ground.
Grounding and bonding
Connecting the electrical system to the earth and tying metal parts together so a fault trips a breaker instead of energizing a pipe or a chassis.
Knob and tube
Ungrounded wiring from before the 1940s, with ceramic knobs and tubes. Often still live in old houses; it cannot be buried in insulation and many insurers will not cover it.
Load calculation
The math an electrician does to confirm the service and panel can carry everything in the house plus what you are adding. Required for panel upgrades and large new loads.
Permit and inspection
Most electrical work beyond replacing a fixture requires a permit and a municipal inspection. It protects you when you sell and when you file an insurance claim.
Romex (NM cable)
The plastic-sheathed cable used for most residential circuits. 14 gauge for 15 amp circuits, 12 gauge for 20 amp.
Service panel
The breaker box where power enters and is divided into circuits. Older 60 and 100 amp panels are often upgraded to 200 amps for EV chargers, heat pumps and modern kitchens.
Subpanel
A second breaker panel fed from the main, often in a garage, shop or addition. Grounds and neutrals are kept separate there.
Surge protector (whole-house)
A device at the panel that clamps voltage spikes from lightning and utility switching before they reach electronics and appliances.
Transfer switch
The switch that isolates the house from the grid so a generator can power it safely. Plugging a generator into a wall outlet can kill a line worker.

Guides.

Reading list.

Articles from around the internet that our Pros trust. They open on the source's site.

  • Electrical Safety Foundation International · ESFI

    Home electrical safety guidance: outlets, extension cords, panels, generators and holiday lighting.

  • Home fire prevention · U.S. Fire Administration

    The leading causes of home fires, electrical among them, and how to prevent them.

  • Safety education · U.S. Consumer Product Safety Commission

    Recalls and safety guidance on electrical products, generators and carbon monoxide.

Articles from HomeMaxx.

All articles
Safety

Dryer vents, extension cords and space heaters: the three fire starters in most homes

Most house fires are not electrical faults inside the walls. They start with three ordinary things that get used wrong. Here is what wrong looks like.

3 min readSeasons

Hurricane season: the house, the plan and the paperwork

June first is the start, and the preparation that matters is done by then, not the week a storm is named. The roof, the openings, the water, the paper and the thirty-day rule on flood insurance.

3 min readSafety

Summer power outages: the generator, the food and the sump

Summer storms take the power out more often than winter ones now, and the two things that go wrong are a generator run in the wrong place and a basement that floods while the pump sits idle. The rules for both.

3 min readSafety

The electrical panel: what to look for, and when to replace it

The gray box in the basement is the one part of the house that can start a fire without anyone touching it. The brands with a history, the signs of trouble, and what an upgrade involves.

3 min readImprovement

Heat pump or new furnace? How to decide

The old answer was that heat pumps are for the South. The equipment changed, the incentives changed, and the answer now depends on your fuel, your climate and your ductwork.

3 min readSafety

Carbon monoxide: the alarm every home needs, and where it goes

You cannot see it or smell it, and it comes from the furnace, the water heater, the car and the generator. What an alarm costs, where to mount it and what to do when it sounds.

2 min readSeasons

The winter checklist: getting a house through the cold months

Fall was for preparing. Winter is for watching. The habits that get a house through to March without a burst pipe, an ice dam or a furnace call at midnight.

2 min readSafety

Holiday lights without a call to the fire department

December is the month for electrical fires and ladder falls. Which lights and cords are safe outdoors, how much a circuit can carry, and the tree rules that matter.

3 min read

From the Pros.

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