Household electricity is grounded parallel circuits
Neutral side, hot side
Neutral side grounded
Two wires are safe. One isn’t. You need to know which is which.
The ground wire. Electrically, the same as the neutral wire. Provide an extra ground
The neutral wire. This side of the plug is larger, so you can’t plug it into the hot side of
an electric outlet.
Circuit breakers limit current, keeping wires cool
The following devices are plugged into outlets on the same 120V circuit in a house. This
circuit is protected with a 15 A circuit breaker.
Computer: 250 W
Heater: 900 W
Lamp: 100 W
Stereo: 120 W
Is there too much current in the circuit – that is, does the circuit breaker blow?
I = ∆V = 250 W/120 V = 2.1 A
900 W/120 V = 7.5 A
100 W/120 V = 0.83 A
120 W/120 V = 1 A
Total current = 11.43
It will not blow.
Safety is a matter of current.
Physiological effect AC current (rms) (mA) DC current (mA)