Voltage Drop
Voltage Drop
When 120 VAC is supplied to a load, that voltage is “dropped” across the load. The load uses all the voltage if it’s the only load or resistance in the circuit. So, if you were to place your meter leads on either side of the load, you would expect to see 120 VAC on your meter.
When you place line and neutral together, you get a short. There is no resistance to resist the flow of electrons.
When you place a resistive load between line and neutral, you get a working load. The voltage is being dropped across the resistance.
Why Does It Happen?
Every wire or component has some resistance. When current flows through that resistance, it “uses up” some of the voltage — this is the voltage drop.
Formula (if you’re curious):
Voltage Drop = Current (Amps) × Resistance (Ohms)