Electical Flashcards
What is “E”?
Volts or electrical pressure
Base unit for the measurement of electrical pressure
What is “I”?
Ampere or intensity
Base unit for measurement of electron flow
What is R?
Ohm
Base unit for measurement of resistance or opposition to electron flow
What is W
Watts
Base unit for the measurement of resistance or opposition of electrical power consumption
Watt= 1 volt x 1 amp
What is the formula for calculating volts?
I x R
What the rule for Rt in a series circuit?
Resistance total is equivalent to all the resistance of all resisters added together
What is the rule for amperage in a series circuit
Amperage is constant or the same throughout the entire circuit
What is the rule for voltage drop in a series circuit?
Voltage drop must equal the total circuit voltage
What is an insulator
A material that has 5-8 electrons in the outer valance ring
Materials that have very few free electrons
What must a tent trailer have?
They must have an automatic disconnect for the lights when folded down
What is the minimum sized wire you can use on a unit?
18 gauge
What are the amps for the size of wire
5a-18G 10a- 16G 15a- 14G 20a- 12G 30a- 10G 40a- 8G 50a- 6G
Where must a current protector be from the battery
5ft from the battery and within 18” of the inside the unit
What is the minimum wiring rating in a trailer
90 degrees
A ground must be?
Readily accessible for inspection and maintenance
Why does an effective circuit consist of?
Power source Conductor Resistance Switch Circuit protection
What the volts for low voltage?
30v-750v
What is the Rt in a parallel circuit?
The resistance total must always be less then the least resistance
What’s is OHMs law?
It takes one volt of potential to move one ampere of current through one ohm or resistance
What is the North American standard hertz per second?
60hertz
How many amps is lethal
100 milli amps
What is extra low voltage and low voltage?
Extra low- 0-30v
Low 30-750v
3 sources of AC power in an RV?
Shore power
Generator power
Inverter power
What is RMS?
What is the percentage is in comparison to peak voltage?
It’s the average usable or practical voltage and it’s 70% of peak voltage
How many branch circuits can
15 amp
30amp
50amp have?
15 can have 1
30 - 8
50- 12
What is the minimum AC wiring that can be used?
14 gauge copper wire
What colour must the neutral be?
The neutral must be a white or natural grey
What must all breaker panels have?
Must have a dead front that needs a tool to take off
What must your do with all AC connections?
They must be inside a junction box and must be accessible for maintenance
What receptacles must be class A GFCI protected?
Exterior plugs
Bathroom plugs
And plug within 6 feet of running water
How many amps is considered lethal
100 mA
What is frequency and what is the North American standard frequency?
Frequency is the number of cycles per second
And the standard is 60 hertz
What is RMS
It is the average or practical voltage and it is .707 or 70 percent of peak voltage
What are the three RV power sources
Shore power
Generator power
Inverter power
How many branch circuits can
15 amp have?
30 “?
50 “”?
15 amp- 1
30amp- 8
50amp- 12
How far along must an AC wire be supported?
In the first 12” of the box and every 5 feet along the run
How fast will a class A GFCI trip?
Within 5 mills amps within 5 mill I second
Where must the shore cord be located?
Must be on the left side within 15 feet of the rear
How far away from the shower must the panel be?
1m
What must wiring have when running through studs?
Must be 1.25 inches away from the outside of the stud or else it must be protected
How many outlets can you put on a 2 wire branch?
Maximum of 12
How many watts before you need to put cooking and cooking appliances on their own circuit?
1500W unless you have a switch
How much extra wire should you have inside the junction boxes?
6”
How do you calculate the converters output?
Divide the output by the input
Eg.
In 12.7v at 50 amps - 12.7x50= 635
Out 120v at 6amps. -120x6=. 720
88%
How does a electronic converter work?
Uses transistors to increase the frequency before stepping down the voltage
How do you properly size a converter?
Take 100% of first 20
Take 50% of the next 20
Take 25% of what’s left
What must you install if you need to put 2 high amperage appliances on one 30 amp breaker?
Must install a selector switch
