Electrical basics
Electrical basics
Volts, amps, watts, hot, neutral and ground in plain English.
Electrical basics, in plain English
You don't need a license to change a bulb or a switch — you do need to know what the words on the package mean. Here's the vocabulary that shows up on every box in the aisle.
Volts
The pressure in the line. Standard household circuits are 120V; ranges, dryers and some A/C run 240V.
Amps
How much current flows. Breakers are rated in amps — most rooms are 15A, kitchens and garages are often 20A.
Watts
Volts × amps. It's what the device consumes; bulbs and appliances are rated here.
Circuit
One breaker feeding a run of devices. Overload it and the breaker trips — that's the breaker doing its job.
Ground
The bare or green wire. It gives fault current a safe path instead of finding one through you.
Neutral
The white wire. It carries current back to the panel and is not the same as ground.
Hot
Black or red. This is the wire that bites — treat every one as live until your tester says otherwise.
GFCI
Trips in milliseconds when current leaks — required at sinks, garages, outdoors and pool areas.
AFCI
Detects arcing from damaged wire or loose connections. Newer bedrooms and living areas require it.
Always shut the breaker off and confirm with a non-contact tester before you touch a wire. A tester costs less than twenty dollars and is the single best purchase in this aisle.