Fanshawe College of Applied Arts and Technology
London
Ontario
Advanced Prints DC Voltage Drop
MJM Sept 18/2014
1.
A remote set of lamps drawing 8.5 amps is being fed from unit
equipment with a #8 conductor. The unit equipment operates at 12
volts and the manufacturer’s specifications allow a 6% voltage drop.
How far can the remote lamps be away from the unit equipment?
Show all calculations.
L
2.
L
12 6 10
 
 7.1  20.047metres
6 5 8.5
A remote set of lamps drawing 5.3 amps is being fed from unit
equipment 33 metres away. The unit equipment operates at 6 volts
and the manufacturer’s specifications do not specify a voltage drop.
What is the minimum size of wire used to feed the remote lamps?
Show all calculations.
L
3.
E Vd I t
   Lt
6 5 I
E Vd I t
   Lt
6 5 I
6 5 4.25
 42.5  34.08 metres
6 5 5.3
#4 awg L   
A remote set of lamps drawing 17.5 amps is being fed from unit
equipment 15 metres away. The unit equipment operates at 12 volts
and the manufacturer’s specifications specify a maximum voltage
drop of 6%. What is the minimum size of wire used to feed the
remote lamps? Show all calculations.
L
E Vd I t
   Lt
6 5 I
#6 awg L 
12 6 15
 
 7.6  15.63 metres
6 5 17.5