Illustrated Theatre Production Guide, 2nd Edition

76 Illustrated Theatre Production Guide 2 ed

The hot wire is connected to the generator on the

side where electrons are being pushed because of the

inductive force. The neutral wire is used to complete

the electrical circuit, but in many ways mimics the

action of a capacitor.

In electronics, capacitors are used to store electrons.

Electrons can be “bunched up” inside a capacitor in

proportion to the voltage pressure in a circuit and

released later on when the pressure drops. The neutral

conductor acts in a similar manner, allowing electrons

a place to rest temporarily. When the voltage pressure

of the sine wave increases, as it does in the positive

quadrant of the sine wave, electrons are fed into the

neutral. When the voltage pressure drops below zero,

electrons begin to move out of the neutral and back into

the hot conductor.

Touching a hot conductor will allow at least some

electrons to flow into your body, a hand perhaps. It may

be that the resistances of the various pathways are such

that you will receive only a tingling sensation. However,

if you are “grounded out” by a puddle of water or some

other method of conduction, you might receive a deadly

shock as the current passes through your heart to get to

the ions in the puddle of water.

Grounding does not guarantee safety. Normally, a

ground wire is used to make AC current safer by provid-

ing an alternate path or circuit for electrons to take that

has less resistance than the pathway through a person’s

body. Because the body acts as a resistor in parallel with

a short circuit, and the ground wire has only the very

small resistance of the wire itself, it will naturally draw

off most of the current. If no ground wire is present,

the full amount of the current will pass through your

body, which can be deadly.

TRANSFORMERS, AC TRANSMISSION, AND

THE POWER LOSS FORMULA

Power on overhead lines runs at a very high voltage,

because that is the most efficient method of transmis-

sion. High-voltage electricity loses less power to resis-

tance over long-distance wires. Power loss in a circuit is

determined by the formula P

LOSS

= P

2

R/E

2

. Because the

value of E is squared in the denominator, the higher the

voltage is, the smaller the total power loss will be for a

given amount of current and resistance. The current

running through transmission lines is actually quite

tiny. The current can be small because a large voltage