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eLectrics > L Safety > Flashcards

L Safety Flashcards

1
Q

What are the six major causes of accidents?

A

Pre-occupation
Ignorance/lack of skill
Over familiarity
Laziness and fatigue
Physical hazards
Horse play

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2
Q

What steps need to be taken to minimise a hazard?

A

Know the hazard
Maintain safety discipline
Develop the habit of noticing potential dangers

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3
Q

What are the basic causes of electric shock?

A

Equipment failure (non contact)
Human error (contact)
Combination of equipment failure and human error

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4
Q

How much current will cause what reaction?

A

1mA- involuntary reaction
10mA- prevent from releasing hold
20mA- physical damage
30mA- can KILL

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5
Q

What is the resistance of a dry body and what happens to resistance if the body is damp?

A

1000 Ohms
Decreases

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6
Q

What is the highest voltage deemed safe in the RN?

A

24 DC V
Lowest unsafe voltage is 30V

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7
Q

What is the result of electric shock?

A

Immediate death or unconsciousness
Paralysis of respiratory muscles leading to asphyxia
Electric burns
Physiological shock

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8
Q

What is the electric shock procedure? (8)

A

Raise alarm
Isolate the person from supply if possible
If not possible stand on a dry insulating material and push or pull casualty clear of contact
Do not touch casualty with hands
When casualty is isolated check for a response

If no response:
Shout for help
Open their airway
Check for normal breathing
Keep shouting for assistance
If first aid trained perform CPR

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9
Q

What are the dangers of tantalum capacitors and how can they be minimised?

A

Filled with sulfuric acid and can explode
Personnel carrying out servicing are to wear face masks

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10
Q

What are the dangers of selenium rectifiers and how can they be minimised?

A

Toxic substances are released when selenium rectifiers burn out during operation
Care must be taken to ensure selenium dust is not inhaled or ingested

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11
Q

What is lotoxane and what measures should be carried out when using it?

A

Only recognised electrical cleaning agent in RN
Should never be sprayed on hot surfaces
Rubber gloves/ PPE should be worn
Used with adequate ventilation

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12
Q

What are the types of radioactive valve and their diagrams?

A

Class one radio active valve –> theta sign
Class two radioactive valve –> trifold symbol with words class 2
Hazard radioactive valve –> trifold symbol and words caution

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13
Q

What PPE should be worn whilst working in the galley?

A

DMS Boots
Overalls/ no. 4s with sleeves rolled down
Chefs hat

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14
Q

Where are the galleys isolating switches and how are they recognised?

A

Outside the galley
Painted red

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15
Q

What is the biggest fire hazard in the galley?

A

Deep fat fryer

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16
Q

As an ETME when are you permitted to work on live equipment?

A

When supervised by an ME senior rate

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17
Q

What precautions should personnel working on live equipment take? (8)

A

Do not take risks
Wear rubber gloves if practical
Use insulated tools if practical
Stand on rubber insulating mats
Avoid leaning on adjacent bulkheads or equipment
Wear insulating foot wear
Beware of voltages
Don’t rely on interlocks
Unless essential do not render interlocks or safety devices inoperative
Do not work alone
Take care so tools don’t cause short circuits
Work with one hand if possible, other in pocket
Check all items of portable equipment have been tested

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18
Q

how do you prove that the equipment is dead?

A

Isolate and carry out the correct tag-out procedure
Prove it is dead by using an item of GPTME, test between phases and phase and earth
Discharge any capacitors
If required fit shorting straps to prevent capacitors recharging

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19
Q

When are the changeover switch operated?

A

Never operated whilst equipment it feeds is running, if possible sight that the motor has stopped turn the starter to the off position. If you cannot see the motor, wait 10 seconds.

20
Q

What are the three types of changeover switch?

A

Normal/Alternative changeover switch
Normal/Emergency changeover switch
Normal/Alternative/Emergency changeover switch

21
Q

When is the term high voltage used?

A

Where the working voltages exceed 1000 V AC or 1500V DC when measured between any 2 phases
600V AC or 900V DC between phases and earth

22
Q

What does the term HV live mean?

A

Informs personnel that the ship is either generating HV is capable of generating HV or is connected to an external HV shore supply

23
Q

What does the term HV dead mean?

A

The ships supply is no longer generating distributing or receiving HV.
All sources are disconnected and isolated with circuit main earths supply.

24
Q

What does the term HV safe mean?

A

Informs personnel that a particular compartment is safe to enter with all forms of HV power source disconnected and the appropriate HV decay periods elapsed.
Used in conjunction with the clearly identified compartment.

25
Q

Who are the key personnel involved in HV control?

A

Authorising Engineer (MEO)
Authorised Person (WO2/CPOET)
Authorised Person in Control (CPOET)
Competent Person (all members of ME department that have been adequately trained, approved by the AE)

26
Q

what is an authorised person in control

A

a person specifically debuted to exercise control of the HV system

27
Q

what is a competent person

A

a person who has sufficient technical knowledge or experience to enable the person to avoid dangers from electrical hazards

28
Q

What documents are required for the control of the HV system?

A

Permit to work
Sanction for test
Limitation access
Switching schedule

29
Q

What forms of energy are released from an arc flash?

A

Heat–>up to 20,000 degrees C
Plasma discharge–>IR radiation
Light–>Very intense UV radiation
Pressure Wave–> Vaporised copper expands up to 67,000x
Shrapnel–>molten copper, insulation, pieces of switchboard
sound at a 2m distance permanent hearing damage
smoke–> contains poisonous vapours and molten particles

30
Q

Describe the LOTO removal procedure (8)

A

1.Obtain permission
2.Sign LOTO safety certificate for removal of LOTO request
3.Collect the correct fuses, Part B and C or LOTO label
4.Ensure circuit isolation switches are open
5.Remove Part A and empty fuse holder using an item of GPTME set to voltage measure across the empty fuseway. If the reading is 0V place fuse in fuse holder and insert fuse holder into empty fuseway, repeat for fuseway 2 & 3
6.Return LOTO labels part A,B&C to senior rate
7.Sign LOTO safety certificate for LOTO removal and closure
8.Close LOTO index sheet entry
9.Destroy all sections of LOTO labels, transfer completed safety certificate to section 6 of the LOTO log.

31
Q

What is the procedure for LOTO?

A
  1. Obtain permission
  2. Identify Isolation points
  3. Inform the Users
  4. Fill out the LOTO index sheet in section 3 collect safety certificate serial number
  5. sign safety certificate
  6. complete the loto labels
  7. ensure circuit is isolated remove fuses and attach part A of label to the empty fuse holder
  8. place par B on LOTO board
  9. attach part C to removed fuse and place in fuse box
32
Q

Why is LOTO used?

A

Allow maintenance to proceed without hazards to the maintainer
Isolate equipment that is defective and its operation may be dangerous
Prevention of the selection of a mode of equipment operation which may be unavailable or dangerous
Where supplies have been provided but is yet to be fitted
Where equipment has been removed

33
Q

What does the LOTO system consist of?

A

LOTO index sheet
LOTO safety certificate
LOTO label
LOTO display board

34
Q

What is the short term LOTO log comprised of?

A

MEO inspection records
Part 1 instructions and procedures
Part 2 audit records
Part 3 short term LOTO index
Part 4 short term system LOTO safety certificates
Part 5 closed short term LOTO safety certificates

35
Q

Why is a long term LOTO required?

A

Equipment which is likely to be out of action for a period in excess of 6 months
Equipment which is redundant and for which authority or guidance for removal is awaited
When electrical supplies have been fitted for equipment but are yet to be installed
When equipment fitted temporarily for a specific operational task or trial has been removed
Short term LOTOs are in excess of 6 months and are yet to be rectified

36
Q

What is the log term LOTO log comprised of?

A

Part 1. Long term LOTO index
Part 2. Long Term LOTO safety certificate

37
Q

Describe the procedure for removing fuses

A

1.place finger firmly in the centre of the fuse holder
2 with free hand unscrew the fuse holder with a fuse key
3. when fully unscrewed firmly grasp the fuse holder, whilst turning head away remove the fuse holder sharply
4. remove the fuse from the fuse holder and replace the empty fuse holder into the fuseway to maintain the dead front, place part A of LOTO label on the empty fuse holder
5. repeat for fuse ways 2 and 3

38
Q

Describe the procedure for replacing fuses

A
  1. collect good fuses attached to part C of LOTO label from LOTO board fuse draw and part B of the LOTO label from the LOTO board, check the equipment is turned off
    2.remove the empty fuse holder from the fuse way and part A of the LOTO label
    3.Using GPTME test for a voltage across the empty fuseway ensuring it is dead, proving that the equipment isolating switch is still open.
    if 0V replace fuse
    if not 0V do not replace fuse recheck the
    equipment isolation switch
  2. when replacing fuse, ensure correct size and rating
  3. looking away, locate the fuse holder onto the busbar
    6.tightening screws by hand then nip tight with fuse key and repeat for fuse ways 2 and 3
39
Q

what 3 steps must be carried out before tagging a system out?

A

obtain permission
identify isolation points
equipment users informed

40
Q

name the dangerous components and their hazards on board a ship?

A

tantalum capacitor–> contains sulfuric acid and may explode
selenium rectifier –> toxic fumes released when burns out
lotoxane –> not to be sprayed on hot surfaces, used in well ventilated areas with rubber gloves

41
Q

what are the precautions that need to be taken when working on dead equipment

A

1.isolate and carry out LOTO procedure
2.use GPTME to prove dead by testing between phases and earth
3.discharge any capacitors using GPTME
4. if required fir shorting straps to the capacitor

42
Q

what is the purpose of shorting straps?

A

to prevent capacitors recharging

43
Q

when is it considered safe to work on live equipment?

A

When supervised by an ME senior rate

44
Q

When you replaces fuses at the fuse panel how do you prove electrical switches are open or not

A

Using GPTME and measure for 0V across the empty fuse ways

45
Q

list 5 example of Human failure that could lead to an electric shock

A

failure to observe proper safety precautions
shoddy work
failure to properly test portable equipment
familiarity
standing in damp surroundings

eLectrics (2 decks)

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