WLE Ch.1 Flashcards
What are the three categories of electrical linework?
construction, maintenance, and repair
Describe construction electrical linework?
Building new facilities
Describe Maintenance electrical linework?
Performed on existing lines or equipment
Describe repair electrical linework?
involves existing lines and equipment but in an emergency situation
What area of OSHA does linework fall under?
construction or general industry
What are the two methods for working on the power delivery system?
Energized and de-energized
What condition is the line in energized work?
the line is hot and is operating at its normal or nominal voltage
What are the three common energized work processes?
Hot sticking, rubber gloving, and barehanding
De-energized work involves protection from what types of energy sources?
normal and abnormal sources
Majority of construction linework is what kind of work?
De-energized
Lines and equipment are considered de-energized after what three steps?
Disconnect, test, and properly ground
What does it mean to disconnect lines and equipment?
lines and equipment removed from normal source. All connections have been opened, locked, and tagged.
T or F: If you can visually see that the fuses are clearly open but the tester still shows the line is hot, it is okay to ground the lines.
False
What piece of equipment provides a low-resistance path to the best available ground.
Grounds
What is the best definition of de-energized?
All supply conductors have been tested for the absence of nominal voltage and grounded so that all phases share the same potential as the earth
T or F: After a line is de-energized it is only possible to be energized again by connecting it back to the source
False, there can be abnormal sources of energy
What are the two different grounding procedures?
EPZ grounding and bracket grounding
What does EPZ stand for?
Equipotential Zone
T or F: Voltage and potential are interchangeable terms.
True
Who qualifies you to perform either energized and/or de-energized work?
Your employer
Which path will current take?
Every available path to objects of different potential
T or F: Current takes the path of least resistance.
False
Who requires proof that a worker is trained and competent?
OSHA
What aspect of safety is focused on with regards to de-energized work?
Protecting workers in case the line becomes energized unexpectedly
What are the only two ways to completely prevent current flow through the lineworker?
insulate and isolate
Protective grounding and bonding are only effective if they do what two things?
minimize the time it takes to trip the circuit and limit current flow and voltage drop across the lineworker’s body
When performing energized work, lineworkers follow what three principles to manage current?
Insulate, isolate, and protect from second point of contact
What is used for transmission voltages: insulation or isolation
isolation
T or F: The human body is a terrible conductor of electricity.
False
How many amps does it take to burn skin and organs?
1 or higher
How many amps does it take to put the heart in v-fib?
about 1/3
What is a simple safety rule to live by in regards to current?
Regardless of voltage any amount is fatal
What are the three major clearance objectives?
Ensure safety, Minimize negative impacts on the electrical system, and Minimize number affected by outages.
What is step 1 for clearing lines and equipment?
Create clearance plan and confirm details, clearance holder
What is step 2 for clearing lines and equipment?
Request clearance in writing, Clearance Holder
What is step 3 for clearing lines and equipment?
Approve clearance and create a switching order, System operator
What is step 4 for clearing lines and equipment?
Disconnect, lock, and tag all normal sources of energy, field operator
What is step 5 for clearing lines and equipment?
Establish and issue clearance, system holder
What is step 6 for clearing lines and equipment?
Test and apply protective grounds, complete work, clearance holder
What is step 7 for clearing lines and equipment?
Verify work is completed. Release the clearance, clearance holder
What is step 8 for clearing lines and equipment?
Return the system to normal. System/Field operator
OSHA uses the term disconnecting means, what is that referring to?
clearance point
What is a clearance point?
Any device that disconnects a line or piece of equipment from a normal source of energy
Does OSHA require visual clearance points?
No
Name all the types of clearance points.
Air switches, single-blade disconnect, open jumper, line recloser, and flying bells
What should you do immediately after operating a switch?
Check the contact position of each phase
Name the phenomenon. A nearby energy source electrifies a disconnected and de-energized conductor.
Induced voltage or induction
What are some other elements that can effect induction?
proximity of lines, radio, television, and microwave towers can also cause induction
Name the phenomenon. When electrical potential doesn’t leave the lines and equipment for some time.
Capacitance
How long does OSHA require you to wait before grounding a disconnected capacitor?
5 minutes
What is the one condition that stops line work?
Lightning
Name the phenomenon. Charge builds up on the surface of a conductor when warm winds blows across it.
Static charge
What are some common reasons for accidental energizing of the lines?
Unexpected operation of a connecting device, switch accidentally falls closed, generator backfeed, and energized lines contacting de-energized lines.
Name the phenomenon? The amount of current that a given system can deliver to a short circuit.
Fault current
What three things occur when a circuit experiences a fault?
Load bypassed, high amount of current flow, and exposure of the weakest point in the circuit
What is important to consider when selecting the proper grounding components?
Size of the grounds. When speaking of fault currents, size matters
What is step potential?
Voltage difference between the feet
What is touch potential?
Voltage difference between the hands and the place you are standing
T or F: Rubber gloves and rubber overshoes eliminate the hazards of step and touch potential.
False, they minimize but not eliminate
T or F: OSHA does not require vehicle to be grounded
True, they only require vehicle barricading
Who is issued clearance and is responsible for completing the work in the field.
Clearance holder
This person gives the permission for a clearance to occur.
System operator
The employee who is physically operating the disconnect devices.
Field Operator
