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Construction safety > Official Electric Sutdy Guide > Flashcards

Official Electric Sutdy Guide Flashcards

1
Q

What are the most frequent electrical citations?

A
  1. branch circuits
  2. Grounding Path
  3. Ground Fault-circuit interrupters
  4. Grounding live parts
  5. Equipment installation and use
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2
Q

About __ workers are

electrocuted every week.

A

5

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3
Q

Causes the deaths of __ of the

younger workforce

A

12%

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4
Q

What are the three direct electrical hazards?

A
  1. Shock, Electrical
  2. Electrocution or death due to electrical shock
  3. Burns
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5
Q

What are the three indirect electrical hazards?

A

Indirect –

  1. Falls
  2. Fires
  3. Explosions
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6
Q

An electrical shock is received when _____ passes through the body.

A

electrical

current

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7
Q

You will get
an electrical shock if a part of your body
completes an electrical circuit by…

A
  1. Touching a live wire & an electrical ground, or
  2. Touching a live wire & another wire at a
    different voltage.
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8
Q

Severity of Shock - depends on:

A
  1. Path of current thru the body
  2. Amount of current flowing through the body (amps)
  3. Duration of the shocking current through the body,
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9
Q

___DOES NOT MEAN LOW

HAZARD!!!

A

LOW VOLTAGE

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10
Q

Hazard 1 -

A

Electrical Shock

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11
Q

Currents above __ * can

paralyze or “freeze” muscles.

A

10 mA

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12
Q

Currents more than ___ can cause a rapid, ineffective heartbeat
death will occur in a few minutes
unless a defibrillator is used

A

75 mA

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13
Q

75 mA is not much current – a small power drill uses ___ times as much.

A

30

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14
Q

mA = milliampere =

A

1/1,000 of an ampere

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15
Q

Hazard 2 -

A

Electrocution

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16
Q

Painful shocks… causing indirect accidents.

A

3mA+ -

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17
Q

 Muscle contraction… “not able to let go”.


A

10mA+ -

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18
Q

Lung paralysis… usually temporary.

A

30mA+ -

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19
Q

Ventricular Fibrillation… is possible

A

50mA+ -

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20
Q

Certain Fatal Ventricular

Fibrillation

A

100mA to 4amp -

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21
Q
  • Severe burns, heart paralysis.
A

Over 4 amps

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22
Q

Hazard 3 -

A

Burns

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23
Q

Most common… shock

related injury

A

burns

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24
Q

How do most people get shocked?

A

By touching Wires -
Touching electrical wiring or
equipment that is improperly
used or maintained

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25
Q

Hands get it -Typically

occurs on hands

A

burns

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26
Q

Hazard 4

A

Falls

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27
Q

Can cause Death -
Workers in elevated locations who
experience a shock may __,
resulting in serious injury or death

A

fall

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28
Q

Hazard 5

A

fires

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29
Q

most commonly caused by current flowing
through high resistance due to faulty wiring igniting
insulation and / or other material.

A

Fires

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30
Q

Heat is created from high ___ flowing through a

wire. This is analogous to two objects being rubbed together.

A

high currents

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31
Q

(At full speed, ‘skin’ of an

SST jet is about __ )

A

6000F

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32
Q

HEAT of Friction - To maintain continuity of

flow, as the diameter of a pipe decreases, the velocity of the fluid must increase, and ____.

A

the heat of friction increases

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33
Q

When a wire decreases in _____ due to damage, current must increase through that portion of the wire, & heat increases possibility to the point that surrounding materials are set on fire.

A

cross-sectional area

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34
Q

Hazard 6

A

Explosions

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35
Q

can be caused when electricity provides

the ignition source (arc) “jumping” through an air-’fuel’ mixture in the atmosphere.

A

Explosions

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36
Q

What should be used Isolate Electrical Parts.

A

covers,
guards
barriers

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37
Q 
Guard live
parts… of electric
equipment operating
at \_\_\_  or more
against accidental
contact
A

50 volts

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38
Q

Conductors going into live parts must be protected,

and unused openings must be closed. What do you use?

A

cabinets,
boxes
fittings

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39
Q

J-boxes (etc) must have

_____ Unused openings must be closed (no missing knockouts)

A

approved covers

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40
Q

Don’t get near power lines! watch out for what?

A 
Cranes
Ladders
Scaffolds
Backhoes
Scissors lifts
Raised dump truck beds
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41
Q

De-energize power lines before working on them. What are two ways this can be done?

A
  1. Lock Out/Tag Out

2. Power Provider to de-energize.

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42
Q

If you don’t want to de-energize power lines then:

A

Guard or insulate the lines

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43
Q

Always Call “One Call”:

A

before digging around underground power lines.

44
Q

Always Locate & De-Energize:

A

before digging

45
Q

Re-Call “One Call” if in Doubt:

A

If obvious signs of utilities (power boxes, poles
etc.) exist but are not marked, call for the locator
to re-mark before working.

46
Q

Select wire size based on:

A
  1. bldg materials,
  2. electrical load, and
  3. environmental factors
  4. operation
47
Q

Use fixed cords:

A

not flexible cords

48
Q

What type of wire must be used?

A

Must be 3-wire type and

designed for hard or extra-hard use

49
Q

Temp Lighting is Temporary:

A

remove it immediately upon completion of construction

50
Q

Protect Temporary Lights from Breakage:

A

use bulb guards.

51
Q

Don’t “hang” Temporary Lights by wires:

A

unless designed for this use

52
Q

When dealing with temporary light, All branch

circuits must come from panel board & ____.

A

have breaker protection

53
Q

NO Temp wiring on floors - 

A

Branch circuits cannot be run on floors.

54
Q

Wall Outlets must have:

A

Covers

55
Q

Protect conductors entering boxes, etc from ___.

A

abrasion

56
Q

Close Unused Openings -

A

in J-boxes.

57
Q

When dealing with temporary wiring use ___ In wet locations.

A

Weatherproof Enclosures

58
Q

When dealing with temporary wiring, protect Hardware from Water, by____.
…

A

Cabinets, boxes, switches, circuit breakers, etc.

59
Q

extension cord rules for repairs:

A
  1. Repairs to Extension Cords - can only
    be made to 12 gauge or larger extension
    cords.
  2. Repairs must maintain insulation -
    Repairs (splices) must maintain outer sheath
    insulation properties (No electrical tape).
    3.Strain relief - must be provided.
60
Q

a low resistance
path from a tool
to the earth to disperse unwanted
current.

A

Grounding

61
Q

When a short occurs,
energy flows through the “___” wire and NOT YOU!! … to the ground, protecting you from
electrical shock, injury and death.

A

ground

62
Q

Energized Tools -
Tools plugged into improperly grounded circuits may become…

A

energized

63
Q

They Automatically
open circuit if unsafe
current is detected – they
“shut off” electricity

A

Electric Circuit Protective

Devices

64
Q

Fuses

A

melt

65
Q

Circuit breakers

A

trip

66
Q

GFCI’s

A

“isolate” the load

67
Q

GFCI cuts electricity
off in ___ of a second if a
ground fault is detected.

A

1/40th

68
Q

Use GFCI’s on all:

A

120-volt, single-phase, 15- and 20-ampere receptacles.

69
Q 
“Tripping” GFCI’s - are designed to trip
at \_\_\_  (painful shock level).
A

4-6 milliamps

70
Q

GFCI’s required on temporary ____ – (not part of permanent wiring system).

A

120v 15-20 amp outlets

71
Q

GFCI not required on permanent power, unless ____.

A

tool used with extension cord

72
Q

GFCI protection is required on all portable generators _____ or greater.

A

5kW (5,000 watts)

73
Q

GFCI protection can be built in or added as a_______.

A

pig-tail

74
Q

Written program –The must be kept onsite.

A

Assured Grounding program

75
Q

Who must implement Assured Grounding Program?

A

competent person

76
Q

What is covered by Assured Grounding Program?

A

equipment (connected by plug & cord),
all cords, plugs, receptacles (not part of a building or
structure), & power tools.

77
Q

When dealing with assured ground, Test Records kept -

A

by color coding, other

means, & by written log.

78
Q

When should assured grounding program be tested?

A

(1) before 1st use,
(2) at least every 3 mo.,
(3) after service, &
(4) after possible damage.

79
Q

Electrical equipment must be inspected before use. What two things should you be looking for?

A

(1) inspected before installation &

(2) suitable for the intended use.

80
Q

All ___ must

be labeled.

A

circuit breakers

81
Q

Access to live parts 50+ volts must be Controlled by what two things?

A

restricted areas or physical locations

82
Q

– (accessible by only
qualified /authorized persons), i.e. room,
enclosure, partition, screened area, balcony,
platform, etc., or by

A

Restricted Areas

83
Q

Elevated 8 feet or

more above the floor or working surface.

A

Physical Locations

84
Q

must be used where

electrical equipment is exposed to physical damage.

A

Enclosures or Guards

85
Q

Electrical Rooms must be ___.

A

marked

86
Q

Must use _____ designed for that purpose (wire nuts) or by brazing, welding, or soldering.

A

splicing devices

87
Q

This must be done to controls on equipment during service/repair with clear identification.

A

lock out/tag-out

88
Q

Circuits or equipment that are de-energized must be ___ to prevent unauthorized reenergizing at any point.

A

locked & tagged

89
Q

At what amperage will a GFCI trip?

A

4-6 milliamps

90
Q 
What type(s) of electrical cords are
acceptable for use in construction?
A

3-wire type & hard or extra hard duty

91
Q

What is the proper way to repair an

extension cord?

A

Repair only 12 gauge or larger; Repair must maintain insulation properties, use shrink sleeve.

92
Q
  1. What should we do to protect
    unauthorized employees from entering
    electrical rooms with live parts?
A

Mark the room with Warning Signs forbidding entrance by unqualified, unauthorized persons.

93
Q

Severity of Shock - depends on:

A
  1. Path of current thru the body
  2. Amount of current flowing through the body (amps)
  3. Duration of the shocking current through the body,
94
Q

Hazardous (Electrical) Conditions

A
  1. Exposed Electrical Parts
  2. Proximity to Power Lines
  3. Inadequate Wiring
  4. Defective Cords
  5. Poor or No Grounding
  6. Overloaded Circuits
95
Q

Power line rules:

A
  1. Keep Away - 10’ – minimum
  2. Post Signs – warning of danger
  3. Assume Lines are “Hot”
  4. Use No Metal - Use wood or fiberglass ladders, not metal
  5. Use PPE - Power line workers need special training & Personnel Protective Equipment
96
Q

What causes damaged cords?

A
  1. Aging, wear
  2. Edges of doors, window
  3. staples or fastenings
  4. Abrasion from adjacent materials
  5. Impact from activity in the area
  6. Don’t Pull on Cords - Remove cords by pulling on the plugs, not the cords
  7. Use Only Hard Service Rated Cords
97
Q

Extension cord rules:

A
  1. Use only 3 wire type, hard duty - All extension cords must be 3-wire type & hard or extra hard duty.
  2. Protect from Damage – must protect flexible cords & cables from damage.
  3. No “Pinch Points” – must not run cords through pinch points.
  4. No Nails, Staples, etc – must not suspend extension cords by nails, staples, or wires.
98
Q

Cords and wiring rules:

A
  1. Use Plugs with Ground Pins - Path to ground must be continuous (only use plugs with ground pins; no missing ground pin).
  2. No Reversing Polarity - No grounded conductor can be attached to any terminal reversing its designated polarity.
  3. Must Have General Disconnect – (Main Breaker) Must have a disconnect that allows all conductors to be disconnected from service entrance.
99
Q

The four grounding rules:

A
  1. Ground your equipment - power supply systems, electrical circuits, and equipment
  2. Inspect frequently - electrical systems to insure path to ground is continuous
  3. Inspect before use - electrical systems and equipment
  4. Don’t remove Ground prongs - from tools or extension cords
100
Q

What are the reasons that circuits get overloaded?

A

a. Too many devices plugged in
b. Using Damaged tools
c. No Over-current protection
d. Melting Wire insulation

101
Q

11.How does a GFCI work?

A
  1. GFCI monitors - the amount of current flowing from “hot” to “neutral”.
  2. GFCI trips the circuit - If it detects an imbalance as small as 5 milliamps,… and it can react as quickly as 1/30 th of a second.
  3. GFCI rendered useless - Never snip off the “ground” prong on a plug; that will negate the safety feature a GFCI provides
102
Q

When should an Assured grounding system be tested?

A

(1) before 1st use,
(2) at least every 3 mo.,
(3) after service, &
(4) after possible damage.

103
Q

Working Spaces

A
  1. Cannot be used for Storage
  2. Must have Access and “Elbow Room” - Sufficient access and working space must be provided and maintained around all electrical equipment.
  3. Work-Space Clearances - Minimum working clearances per Table K-1.  3 ft2 – In front of the elec. Equip. (in the direction of access to the live parts).
104
Q
  1. Lockout/Tag out of Circuits
A
  1. Apply locks to power source after de-energizing
  2. Tag (de-activated) controls
  3. Tag (de-energized) equipment and circuits at all points where they can be energized
  4. Tags must identify equipment or circuits being worked on
105
Q

. Protect employees from electrical shock:

A
  1. Use barriers/guards –
  2. Pre-plan work - post warnings & use protective measures
  3. Keep work areas clear - of cords, debris, trip hazards
  4. Cord Safety
  5. Plan your work with others
  6. Plan to lock-out/tag-out equipment
  7. Remove jewelry
  8. Avoid wet conditions
  9. Avoid overhead power lines
106
Q

Train employees - to use safe practices including

A
  1. De-energize before starting to work
  2. Use only cords, tools, etc that are in good repair
  3. Lockout/Tag out procedures
  4. Use PPE Proper Protective Equipment

Construction safety (24 decks)

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