3-2 Test Flashcards
In labor relations if two parties cannot agree the matter is turned over to a their party who makes the decision this is called ?
Arbitration
A ___ should be used to solve a problem not to win an argument
Grievance
The pathway that current takes in a workers body
Directly impacts the severity of the electrical shock
The human body’s reaction to a 16 ma current flow is a
Muscle contraction
The Relationship among resistors in a series circuit is that they
Combine to equal a total resistance
The characteristic of a series circuit is that it has
One continuous path for current flow
Which of the following is still a commonly used yet incorrect grounding protection scheme and is the most dangerous method still in use today ?
Bracket grounding
The schematic represents a grounding scheme with
Ground cables connected from each phase to common ground
Should a line become energized an equipotential zone maintained the current between the workers contact point and feet to
An acceptably low level
The federal regulation stating the order connection and removal of power line grounding jumpers is found in osha
1910.269 sub part r
To establish an equipotential zone at a work site a ___ must be placed in parallel with the worker
Low resistance shunt
A pole down ground should not be used as the only connection to earth when grounding a line because it might
Fuse under fault current
Jacket material on grounding cables is normally rated at
600v
If there is no pole ground present what step must be taken
An additional ground must be attached from the cluster bar to a driven ground rod
Grounding jumpers and components must meet the ___ f855 governing standard
ASTM
The smallest cable allowed for grounding is
2 AWG
When applying protective grounds the first connection should always be
The ground end
One danger from grounds during the fault current flow is
Cable whipping
A worker is standing in a conductive ground mat that has accidentally become energized the first step off the mat will
Bridge the maximum voltage drop
Rubber overshoes worn to protect against touch and step potential are manufactured in accordance ___ standards
ASTM
The surface area of an equipotential zone can be extended with the use of
Ground mats
When grounds are applied in such a way at that a closed circuit is formed through the line and earth return a type of ____ transformer is created
Air core
If an isolated line is capacitive coupled to an energized line ___ earth connection are required for the line to be taken to zero at that point
1
Workers at ground level can be subject to nuisance shock caused by ____
From nearby lines
Capacitive coupled voltages
If a boom contacts an energized line a worker standing near but not touching the truck is in danger of
Step potential
Electromagnetic ____ causes current flow in circuits completed by the earths paths
Induction
A truck with an uninsulated boom is bonded to a driven ground rod if the boom contacts an energized line fault current will flow through
All points of earth contact
When workers are injured it is often the result of misidentified phases bad neutrals and
Unsafe work practices
A ___ is used to ensure a URD cable is electrically isolated before cutting it
Spiking tool
The best method of establishing an EPZ around a urd transformer in the field is to
Connect and use a portable ground mat
Grounding jumpers fitted with ___ clamps are designed to fit tubular bus with a diameter up to 2.88 inches
All angle
Before grounding lines or equipment in substations ___ must be discharged
Capacitors
Asymmetrical current caused by the large amount of inductance present from transformers and reactors versus the small amount of resistance present in the substation _____
Buses
To reduce the current through a ground rod additional driven grounds can be paralleled. These additional rods must be spaced
Twice the distance they are driven into the earth
When current is introduced to a ground rod the current will flow away from the round rod in ____ directions
All
A ___ depends on several factors to establish a low ground resistance the earth it is in the contact it is making with the earth the type of rod used and the length
Ground rod
The main reason to extend a ground rods length in poor soil is to get closer to
Moisture
Using a fall of potential test when testing a ground rods resistance connection to the earth ____ temp probes must be used
3
In theory by adding more length to a ground rod the resistance
Decreases
The two main ground resistance tests used in the electrical industry is the fall of potential test and the
Clamp on ground tester
Lightning generates heat in a ___ path of approximately 60,000 degrees three times hotter than the surface temp of the sun
2.5 cm
If the charge in the cloud increases beyond the critical breakdown point of air what will occur
Lightning
______ is the most frequent cause of transient faults
Lightning
A lightning strike discharges from clouds to the earth containing millions of volts and currents ranging from 2,000 to ___
200,000
When talking about LAS the initials MOV means ?
Metal oxide varistors
The maximum discharge voltage of an LA should be ___ less than the BIL of the equipment that is to protect
20%
A ____ type arrestor would be installed in a 230 kv switch yard
Station
The ____ relives the line to wich it is attached of the greater than normal voltage impressed on it by events such as lightning and prevents the further flow of power current
Lightning arrestor
For a lightning arrestor to successfully fulfill its function it must be properly coordinated with the ____ it is protecting
Equipment
