Practical Electricity Module Assignment Flashcards
What are the 2 hazards of electrical shock
- Burns
- Affect the heart(electrical system of body)
Why should you not open disconnects under load?
The blades of the disconnect aren’t designed to open under load, they move too slow to extinguish the arc cause by breaking a circuit.
Each person working on a piece of equipment must ______ ______ before proceeding with the work.
Lock Out
Before turning off the disconnect or breaker for a piece of equipment for lockout purposes, you must…..
Shut equipment off at control centre.
Why are tags used in addition to locks when locking out equipment?
They provide a reason to why the equipment is locked out.
Why is a missing junction box cover a hazard?
Dust and Water can enter causing a fire
What do dimly lit lamps indicate?
A low voltage condition, get electrician to investigate.
Circuit breakers are _________ acting than fuses.
Slower
What is the difference between a disconnect and a circuit breaker?
A disconnect uses fuses to open the circuit when a fault level is reached.
A circuit breaker uses magnetic and thermal sensing devices to trip a mechanical circuit opening switch.
What are the two main actions a fuse takes when its link melts?
- Opens the circuit
- Limits the current to a safe level
What should you do before using a multimeter?
Read the instruction manual
What should you do when measuring voltage of an unknown value?
Start at the highest setting, decrease setting as needed.
What is the critical thing to be sure of before measuring ohms?
That there is no power in the circuit under test.
The ammeter part of a multimeter must always be connected in _______ with the load.
Series
What precautions must you take when reading voltage or amperage?
Do not come into contact with any live parts
For what is a megohmmeter used?
Megohmmeter measures insulation resistance in cables and motors. This high voltage instrument usually detects any leakage current to ground.
What is the typical colour code for a 2-wire 120V AC circuit?
Black = Hot
White = Neutral
Copper or Green = Ground
What is the purpose of the ground wire in any circuit?
It keeps the metal enclosure of an electrical piece of equipment at ground potential, preventing electrical shock. Also carries fault current in event of a conductor accidentally grounding causing a fuse/breaker to trip, opening the circuit.
For smaller wire, the ______ the gauge number, the __________ the wire
For smaller wire, the higher the gauge number, the smaller the wire.
Copper is a better conductor than?
A lot but module states;
Aluminium and Gold
Who ensures electrical code compliance?
The regulatory authority in the jurisdiction of area.
After the motor is running, what reading should you take?
Current
Why is it important to keep the exterior of motors clean?
For cooling, the exterior of motors dissipate heat.
What is RMS?
Root means square
- if DC then the RMS and currents are the same. If the current is AC, then the RMS current is 0.707(70%) of the maximum current.
