A2 Lt 13-14 Flashcards
(13 cards)
what are some advantages of a 3 wire system
ampacity capacity can be reduced, two different voltages are available (120/240), line drop and line loss are reduced, improved safety through grounding the neutral.
What is the voltage line to line in a three wire circuit
240v
What are the common colors for a three wire circuit
white for neutral, black and red for lines
Main reasons for grounding
Guards against Electrical Shock and fire hazards
The shock is reduced by what percent when you ground the neutral
50%
What is the definition of a balanced 3 wire circuit
When an equal amount of load resistance is connected across each of the 120 V lines to neutral sections of three-wire circuit, we have what is called a balanced load condition.
Advantage of a balanced circuit
Having zero amps in the neutrals means, we don’t have any Line Loss in our Neutral which saves money. Also nothing will happen if neutral is broken.
When does the neutral carry current
Only in a unbalanced circuit
The sum of all voltage drops in a loop must equal
The source voltage
A voltage rise is
current flowing in the opposite direction of your loop
Best first step to solving three wire circuit problems
Draw in current direction and amount at each junction
The way to find current in the neutral wire in any section is always
the difference between the currents in the hot section…the direction is the same as that of the smaller of the two hot wire currents
Never do what three things to a neutral
fuse, switch or open while circuit is live
