Amp (Ampere)
The unit of electrical current: how much electricity is flowing through a wire at a given moment. Breakers, wires and your whole electrical service are all rated in amps.
Think of amps as flow rate. A phone charger sips a fraction of an amp, a space heater pulls 12.5, an electric dryer draws 30, and a whole modern house is served by 100 to 200 amps coming in from the utility. Every component between the power line and your toaster (service entrance cable, panel, breakers, branch wiring, outlets) carries an amp rating, and the system is designed so the weakest link is always the breaker, which trips before anything overheats.
Amps are the number that drives most real-world electrical decisions: whether your panel has room for an EV charger, whether a circuit can take a second freezer, whether your 1960s 60-amp service can run a modern kitchen. When an electrician talks about "capacity," amps are what they are counting.
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- Kilowatt-Hour (kWh) : The unit your utility bills you for: one kilowatt of power used for one hour.
- 120V vs 240V : US homes receive two 120-volt legs from the utility.
- Voltage Drop : The loss of voltage along a wire run, caused by the resistance of the wire itself.