Тест по Electrical Safety (CES v5.0)

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Правильні відповіді:
1

At voltages of less than 1 000 V, what is the generally accepted minimum value of insulation resistance for electrical equipment on board ships?

Ваша відповідь правильна:

One megohm (1 MΩ).
2

For a ship’s electrical system, which one of the following statements best describes the meaning of the term “earth”?

Ваша відповідь правильна:

The steelwork of the hull, whose electrical potential can be regarded as zero.
3

If a fluorescent tube or energy saving light bulb breaks, in addition to ensuring good ventilation, which one of the following statements best describes how the pieces should be cleaned up?

Правильну відповідь:

Use rubber gloves, sticky tape or wet towels to clean the area, place all materials in a marked sealed container for disposal ashore.

Ваша відповідь:

Sweep the pieces up with a brush and place all materials in a marked sealed container for disposal ashore.
4

If any part of a live electrical circuit is brought into accidental contact with earth, then which one of the following statements should we assume to be correct?

Ваша відповідь правильна:

It is an unsafe situation.
5

If unsure whether electrical equipment is live or not, the best course of action to take is to:

Ваша відповідь правильна:

Treat it as though it were live until a competent person has proved it dead.
6

If work is to be carried out only on one part of a lighting circuit controlled by fuses or a miniature circuit breaker (MCB), which one of the following options is the best way to proceed?

Ваша відповідь правильна:

Switch off all the other lights first and then withdraw the fuses or MCB for the whole circuit.
7

Once you are sure the power has been turned off, what is the next step in helping someone who has received an electric shock?

Ваша відповідь правильна:

Check airway, breathing and circulation.
8

Outside of a hazardous area, which one of the following statements best describes the choice of portable electrical equipment when working in wet areas or galleys?

Ваша відповідь правильна:

Portable electrical equipment supplied from a 110 Volt centre-tapped transformer should be used rather than mains voltage equipment.
9

The flow of unwanted leakage current through surface deposits on electrical cables is known as which one of the following?

Ваша відповідь правильна:

Tracking.
10

The relationship between voltage, current and resistance in an electrical circuit can be described by which one of the following statements?

Ваша відповідь правильна:

The higher the voltage, or the lower the resistance, the higher the current.
11

What should be your first action if you see someone receiving an electric shock?

Правильну відповідь:

Turn off the electrical supply or get the victim clear of any live electrical conductors.

Ваша відповідь:

Grab hold of the victim to prevent them falling.
12

Which THREE of the following are true reasons why electrical equipment needs to be designed and approved for use in a hazardous area?

Правильну відповідь:

Explosive gas can enter equipment.; High energy sparks can ignite flammable gasses.; Working temperatures can reach the ignition temperature of the gas.

Ваша відповідь:

Working temperatures can reach the ignition temperature of the gas.; Even very low voltage or current is dangerous in hazardous area.
13

Which TWO of the following conditions should be met before working on or testing any electrical equipment in a hazardous area?

Ваша відповідь правильна:

A permit to work system should be used.; Only component, suitably trained and experienced persons should carry out the work.
14

Which one of the following current paths for an electric shock is considered the most dangerous to the human body?

Ваша відповідь правильна:

From hand to hand, across the chest.
15

Which one of the following gasses is given off during the normal charging of vented lead-acid batteries?

Ваша відповідь правильна:

Hydrogen.
16

Which one of the following is the main purpose of a rubber mat placed on the floor next to electrical equipment?

Ваша відповідь правильна:

To provide an insulating surface to reduce the risks from an electrical shock.
17

Which one of the following options correctly completes the following statement? Electrical equipment is said to be “live”…

Ваша відповідь правильна:

When it is supplied with or contains an electrical voltage or current.
18

Which one of the following options correctly completes the following statement? Electrical equipment is said to be “dead” when…

Ваша відповідь правильна:

It is not connected to an electrical supply and any stored electrical energy has been discharged.
19

Which one of the following statements best describes a safer alternative to checking voltages on live electrical equipment during fault finding?

Ваша відповідь правильна:

Make the circuit dead and carry out low resistance (continuity) tests.
20

Which one of the following statements best describes how much electrical resistance the human body has?

Ваша відповідь правильна:

The resistance of the human body decreases with higher voltages, sweat or damp conditions.
21

Which one of the following statements best describes the testing of live electrical equipment?

Ваша відповідь правильна:

Live testing should only be carried out by competent persons using approved equipment and PPE, and only when essential.
22

Which one of the following statements best describes which voltage level can be considered as “safe”?

Ваша відповідь правильна:

Below 50 Volts is generally considered safe as regards electric shock, but lower voltages still present some risks.
23

Which one of the following statements best describes why meter test leads should have finger guards fitted?

Правильну відповідь:

To prevent accidental contact between the hands and conductors which might be live.

Ваша відповідь:

To prevent injury to the hands from the sharp edges of test probes.
24

Which one of the following statements correctly describes how batteries or their contents should be disposed of?

Ваша відповідь правильна:

Batteries and their contents should always be treated as controlled, special waste.
25

Which one of the following statements defines what we mean by a “hazardous area”?

Ваша відповідь правильна:

An area where a flammable gas atmosphere is, or may be, expected to be present.
26

Which one of the following statements most accurately defines the term “portable electrical equipment”?

Ваша відповідь правильна:

Electrical equipment that is connected to the supply by a cable through a plug and socket.
27

Which one of the following would be the minimum current level above which an electric shock could be considered potentially fatal for to the average person?

Ваша відповідь правильна:

Twenty-five milliamps (25 mA).
28

Which one of these is the main purpose of electrical cable insulation?

Правильну відповідь:

To prevent current from flowing anywhere, other than through the conductors.

Ваша відповідь:

To protect the conductors in the event of a fire.
29

Which one of these is the most important effect of deposits of dirt, chemicals, or oil on electrical cables?

Правильну відповідь:

The cable insulation resistance will be reduced.

Ваша відповідь:

The cable insulation resistance will be increased.
30

Which one of these statements best describes persons who should carry out electrical work on board ship?

Ваша відповідь правильна:

Only those who are trained, experienced and therefore competent.
31

With regard to an insulation resistance test on electrical equipment, which one of the following statements best describes where the insulation resistance should be measured?

Ваша відповідь правильна:

Between each conductor and earth, and between each of the conductors.
32

With regard to an insulation resistance test on electrical equipment, which one of the following statements gives the correct sequence for connecting and disconnecting the test leads?

Правильну відповідь:

Connect the earth lead first, before the live lead. Remove the live lead first, and the earth lead last.

Ваша відповідь:

Connect the earth lead first, before the live lead. Remove the earth lead first, and the live lead last.
33

With regard to work on electrical equipment, which one of the following statements best describes how equipment should be proved dead?

Ваша відповідь правильна:

By using an approved voltage testing device or voltmeter at the point of work.
34

With regard to work on electrical equipment, which one of the following statements best describes how equipment should be safely identified?

Правильну відповідь:

By observing at the point of work that it starts/stops when its control circuit is operated.

Ваша відповідь:

By asking the Chief Engineer.
35

With regard to work on electrical equipment, which one of the following statements best describes how it can be ensured that equipment remains safely isolated?

Ваша відповідь правильна:

By posting a caution notice anywhere that the equipment has been isolated, and locking off switches or removing fuses whenever possible.
36

With regard to work on electrical equipment, which one of the following statements best describes the term “isolated”?

Ваша відповідь правильна:

Disconnected from any electrical supply, and physically separated from it by an adequate gap.
37

With regard to work on electrical equipment, why is the use of multimeters not recommended for proving equipment dead?

Правильну відповідь:

It is too easy to have them on the wrong measurement scale, and in some cases this can also be dangerous.

Ваша відповідь:

Only analogue instruments should be used, and multimeters tend to be digital devices.
38

With regard to work on electrical equipment, why should a special insulation resistance meter be used for checking insulation resistance, rather than a multimeter?

Ваша відповідь правильна:

The insulation resistance meter applies a test voltage of 500 Volts which gives a more realistic test.
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