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Electrical Engineering > Safety > Flashcards

Safety Flashcards

1
Q

What are the top causes of accidents with electricity?

A
  1. Unintendedly working on active wires 32.9%
  2. Working nearby active wires without performing electrical work 18.5%
  3. Intentional working on active wire 15.3%
  4. Working nearby active wires while performing electrical work 12.6%
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2
Q

What parts of human neurological systems use electricity?

A
  • Cardiac beat initiation
  • Excitation of muscles
  • Impulse Nerve cell transmission
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3
Q

What are smooth and striated muscles used for?

A

Smooth muscles used for enduring processes

Striated muscles used for fast powerful contractions

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4
Q

What can musculature be categorized into?

A

Slow and fast twitch muscles

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5
Q

Whats are characteristics of the Sinoatrial node?

A
  • 60-80 beats per minute
  • Primary excitation unit
  • Connected to muscles of Atria
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6
Q

What are some characteristics of Atrioventricular node?

A
  • Secondary excitation unit
  • 40-50 beats per minute
  • starts when sinus node fails
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7
Q

What are some characteristics of His-bundle?

A
  • Tertiary excitation unit
  • 20-30 beats per minute
  • When AV node fails
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8
Q

What are the six sequences of a heartbeat?

A
  1. Sinus node emits impulse
  2. Atria contracts
  3. Impulse transmission to AV
  4. Delayed contraction of ventricles
  5. Complete excitation of heart muscles
  6. Relaxation of muscles
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9
Q

What is the range of body resistances?

A

250 - 500 - 750 -1000

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10
Q

What is safety extra-low voltage for AC?

A

V < 25

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11
Q

What is extra-low voltage for AC?

A

25 < V < 50

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12
Q

What is low voltage for AC?

A

50 < V < 1000

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13
Q

What is high voltage for AC?

A

1000 < V < 200kV

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14
Q

What is maximum voltage for AC?

A

V > 200kV

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15
Q

What is Safety extra-low voltage for DC?

A

V < 60

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16
Q

What is extra-low voltage for DC?

A

60 < V < 120

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17
Q

What is low voltage for DC?

A

120 < V < 1500

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18
Q

What is high voltage for DC?

A

1500 < V < 200kV

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19
Q

What is maximum voltage for DC?

A

V > 200kV

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20
Q

What is the RMS value?

A

Root-mean-square value

time average

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21
Q

What is the formula for peak voltage in terms of rms

A

V = \sqrt{2} * V_rms

22
Q

What is the conductor color code in Deutschland?

A

Line conductor - Brown, black or gray

Neutral - Blue

Protective Earth - yellow-green

23
Q

What is emergency shutdown?

A

Switching off power supply. Does not brake moving parts

24
Q

What is emergency stop?

A

Shuts down power and brakes moving parts

25
Q

What are the safety sign categories in Deutschland?

A
  1. Warning
  2. Prohibition
  3. Mandatory
  4. Rescue
  5. Fire Protection
26
Q

What does the exclamation sign mean?

A
  • General warning
  • potential danger
  • usually followed by another sign
27
Q

What does the Blitz sign mean?

A
  • Warning of electrical voltage
  • presence of live parts
  • supplemented by voltage indication
28
Q

What does battery sign mean?

A
  • Indicates facility with battery storage systems
  • Maintain ventilation and avoid acid
29
Q

What does magnet sign mean?

A
  • High magnetic fields
  • Danger due to magnetic force
  • Magnetic data carriers erased
30
Q

What does 4g sign mean?

A
  • Non-ionizing radiation
  • danger due to force of electromagnetic fields
  • Radiation > 400 nm, no gamma, x-ray or ultra-violet
  • Danger from thermal effect of radiation
31
Q

What does the gunbarrel sign mean?

A
  • Equipment with moving parts
32
Q

What does the no love sign mean?

A
  • No access for person with pacemaker
  • High magnetic or electromagnetic field
33
Q

What does the no switch sign mean?

A
  • No switching
  • Hazard from switching action
34
Q

What does the blue switch sign mean?

A
  • release before maintenance or repair
  • will lead to life threatening conditions if not disonnected
35
Q

What does the 1up sign mean?

A

Indicated location of defibrator

36
Q

What installation to which distance must be kept even in the absence of signage?

A
  • DB railroad systems
  • Underground and tramway systems
  • High-voltage masts, underground cables and power
    engineering installations.
  • All types of defective electrical equipment.
37
Q

What is technical voltage range in medicine?

A
  • High voltage > 1000
  • Low voltage < 1000
38
Q

Why is AC more dangerous than DC?

A

In healthy case muscles
react to alternating electric stimuli, which are disturbed by
higher frequency currents

39
Q

What happens when a live conductor is touched?

A

Tetanic muscle contraction can occur, causing muscles to tense to such an extent that muscle and tendon ruptures, strains, and bone fractures can occur, and a conductor can become inextricably
clasped.

40
Q

What kind of injury predominates below 100 V?

A

Damage caused by excitation to heart.

41
Q

At what rate can heart no longer transport blood and what is it called?

A

50-fold frequency: Ventricular fibrillation.

42
Q

What is an additional source of death below 1000V except heart problems?

A

Respiratory muscles may go into high-frequency tremor, preventing productive breaths and resulting in death by suffocation.

43
Q

What kind of damage occurs after 1000V?

A
  • Damage by combustion and charring predominates
  • Temperatures of 3000 - 20k reached
  • Entry and exit marks are left
  • Blood boils can have afteraffects
44
Q

What are the rules for using electrical appliances? (8)

A
  1. Convince yourself of the perfect condition of the operating equipment: Do not use damaged parts, supply lines or equipment. Do not pinch or kink any cables.
  2. Only operate parts intended for operation: Switch on and off via switches, not by unplugging, do not bypass safety devices!
  3. Do not operate wet equipment: Do not operate any devices in the rain or near water. Do not allow connection lines to hang in the water! Make sure that your hands and
    feet are dry!
  4. In case of malfunctions, immediately disconnect the power supply safely: Disconnect devices or better remove the fuse first. Do not reinsert any fuses before the fault has
    been rectified! Do not stick any circuit breakers!
  5. Report malfunctions and damage: Immediately report heat generation, sparking, odor generation, smoke generation or other signs of irregular operation to a qualified person.
  6. No tinkering with electrical systems or equipment: Modification and extension of an electrical system is allowed only to skilled personnel! Cables are not patched, Youtube videos are life-threatening for laymen.
  7. Switch cabinets, fuse boxes and distribution boxes must not be opened: Fuse boxes must even be sealed by the
    power company.
  8. Do not work alone on live equipment: In the event of a fault, life-threatening situations cannot be resolved alone
45
Q

What are safety rules for electrical accidents?

A
  1. Turn off: Switch off voltage or disconnect equipment.
  2. Secure against restarting: Secure switches, put outlets out
    of service, make arrangements, post signs.
  3. Check absence of voltage: Check voltage with meter. To do this, check the meter for function before use.
  4. Ground or short-circuit: Connect live system parts to ground or neutral.
  5. Cover live parts: Surrounding parts may still be live even
    when disconnected.
46
Q

What is a line circuit breaker?

A
  • Fuse
  • Breaks circuit if a current flows over a period of time
47
Q

What is a Residual current device?

A

Monitors circuit to check if current is flowing back through the neutral

48
Q

What is the Arc fault detection unit?

A
  • Monitors for arc fault signatures
  • Interrupts circuit to prevent fire
49
Q

What are the steps for medical assistance in electrical accidents?

A
  1. Own Safety First
  2. Early Emergency call and resuscitation
  3. Obtain overview of voltage level and ways to disconnect
  4. Do not work alone
  5. Observe safety distance of 1 cm per 1000 volts
  6. Look for discharge voltage patterns
50
Q

How do you vary step sizes as you get closer to high voltage?

A

Take smaller steps as you get closer

Electrical Engineering (5 decks)

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