1-2 / lesson 5 Shock, arc, and blast

For arm and hand protection against electrical shocks, ? is considered the best material for insulating gloves and sleeves, and must conform to ANSI standards. a. cotton b. kevlar c. leather d. rubber

d. rubber

An arc generated at 480 volts can be just as dangerous as an arc generated at 13,800 volts. Select one: True False

true

Head protection for workers exposed to electrical shock must be designed to provide protection against an accidental electrical contact. Select one: True False

true

One way for a person to receive an electrical shock normally occurs when he or she makes contact with one part of an energized circuit and the ground. Select one: True False

true

Resistance to the flow of electricity is measured in ? . a. amperes b. ohms c. volts d. watts

b. ohms

One of the factors that determine the resistance of a material is the ? of the substance. a. age b. temperature c. viscosity d. weight

b. temperature

When it is dry, the outer layer of skin may have a resistance of several ? , but when it is moist, there is a radical drop in resistance. a. hundred ohms b. thousand ohms c. hundred thousand ohms d. million ohms

b. thousand ohms

The skin has a "breakdown" voltage at which point it is "punctured," leaving only the lower resistance body tissue to impede the flow of current. This voltage will vary with the individual, but is in the area of ? . a. 120 V b. 240 V c. 600 V d. 13,200 V

c. 600 V

The hand-to-hand resistance of a Qualified Electrical Worker working on a circuit is 5,000 ohms. The circuit voltage is 480 volts. The amount of current that would flow in the worker's body if he becomes part of the circuit is ? . a. 66 mA b. 86 mA c. 96 mA d. 106 mA

c. 96 mA

The possibility of cardiac arrest, severe burns, and death can occur when an electrical shock of ? occurs. a. 2,000 mA b. 4,000 mA c. 7,000 mA d. 10,000 mA

d. 10,000 mA

A severe shock can cause considerably more damage to the body than ? . a. a car accident b. a fall from a pole c. from a severe pinch point d. is visible

d. is visible

Electric shock can cause loss of ? , resulting in the inability to let go of an electrical conductor. a. brain function b. heart function c. lung/breathing function d. muscular control

d. muscular control

The "let-go" threshold for a man receiving an electrical shock is between 9 and ? . a. 30 mA b. 60 mA c. 80 mA d. 100 mA

a. 30 mA

An outside electric current with as little as ? can upset the rhythmic, coordinated beating of the heart by disturbing the nerve impulses. a. 75 mA b. 90 mA c. 100 mA d. 112 mA

a. 75 mA

It is important to understand three things about electricity in order to work with it safely: how parts of the human body react to it, how it can be directed, and how it ? . a. acts b. builds current flow c. creates heat d. grounds itself

a. acts

The ? part of an electrical arc is caused by the pressure developed by the near-instantaneous heating of the air surrounding the arc and from the expansion of the metal as it is vaporized. a. blast b. incendiary c. percussion d. shock wave

a. blast

An electrical shock occurs when the ? becomes a part of the electric circuit. a. body b. hand tools c. live line tools d. worker's clothing

a. body

Burning becomes the major effect on the body at ? . a. 480 V b. 600 V c. 1,000 V d. 2,400 V

b. 600 V