Monarch SE 2004-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Section 8 Electrical System | 295
Branch circuit breakers supply AC power to the different items or “loads.” An
electrical load is any item or device that will use current when supplied with an
electromotive force. Should a breaker “trip” from over current use, or a short
circuit condition, the load to which the breaker is supplying the electromotive
force should be reviewed or disconnected to determine the cause of the trip. If no
cause is found, or not readily apparent, reset the breaker by toggling the breaker to
the OFF position, then back to ON. Should the breaker trip again after the load is
reapplied it may indicate a fault with that particular load. Do not continue to reset
breaker until the problem has been diagnosed and corrected.
Breaker current ratings are current set points in which the breaker is designed
to operate. The internal configuration of the circuit breaker is designed to trip
when excess current is drawn through the breaker. The trip action of the circuit
breaker can occur within milliseconds due to the speed at which electricity can
travel. Breaker ratings are set to operate on a continuous load at 80% of the breaker’s
rated capacity. For example: A breaker with a 20 Amp rating will handle a
continuous load of 16 Amps. This designed set point is when an inductive load is
applied, such as when an electric motor turns on. As the motor starts to spin,
current consumption may momentarily exceed the rated capacity of the breaker.
As the electric motor comes up to operating speed the electric motor’s current
consumption will fall. The AC current load then falls back into the breaker’s rated
80% set point. This electric principle should be kept in mind when using anything
other than 50 Amp shore service and using appliances with electric motors. When
using outlets care should be considered when applying loads such as electric
motors, heaters, coffee makers, toasters, hair dryer or other large current consuming
loads. If the current rating of a load is not known it is usually stated on most
electrical items. The rating will either be in amps or watts. Current ratings stated
on electrical items will change slightly with voltage fluctuations. As voltage
increases current consumption decreases. As voltage decreases current consumption
increases. This may explain why in some instances items operated at borderline
voltage to current tolerances may seem fine in one location but problematic in
another.
NOTE: To calculate watts to amps simply divide the watt figure
by the voltage of which the item operates from. For example:
The electrical item is rated at 1370 watts. Divide that by the
operating voltage of 115 Volts which equals 11.913 Amps. Use
this formula to calculate load to current supply ratio.
The chassis fuse boxes are placed in two locations. One panel is located inside
the motorhome under the dash panel. The box located under the dash is referred to
as the Central Junction Box.
The other panel is located outside, mounted on the front firewall. This box is
referred to as the Power Distribution or the Battery Junction Box.
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