Electrical Safety Flashcards
(26 cards)
Name 6 electrical hazards.
- Exposed wire.
- Working live.
- Exposure to hazard.
- Fire.
- Damaged earth wire.
- Exposed to water.
Define electrical shock.
The physiological reaction, sensation or injury caused by electric current passing through the human body.
When does electrical shock occur?
Occurs upon contact of a human body part with any source of electricity that causes a sufficient current through the skin, muscles or hair.
What are the 6 major types of incidents?
- Pre-occupation.
- Ignorance or lack of skill.
- Over familiarity.
- Tiredness/fatigue.
- Horseplay.
- Physical hazards.
How do we tackle the accident problem? (5)
- Know the hazard, know the precaution.
- Maintain safety discipline.
- Develop habit of noticing potential dangers.
- Learn first aid procedures.
- Be fully aware of all hazards.
Causes of electric shock. (8)
- Equipment failure (indirect contact)
- Human error (direct contact)
- A combination of both the above.
- Failure to observe proper safety precautions.
- Over familiarity.
- Shoddy work.
- Not reporting defective components.
- Failure to inspect/test portable equipment.
Draw the current - effect table.
Current Effect
1mA Involuntary reaction.
10mA Prevents releasing your hold.
20mA Physical damage.
30mA Can kill.
How much resistance does the human body have? (Wet + Damp)
Dry - roughly 100k ohms.
Damp - less than 1k ohms.
What voltage is (technically) considered safe in the rn?
24v DC.
How many volts and amps required to kill a human.
V - 30V.
A - 30mA.
What is LOTO?
LOTO (lock off/tag out) is a SSOW (safe system of work) used to lock off a system for maintenance and repairs.
Is LOTO the only safeguarding measure required?
LOTO is only a minimum and other safeguards can be employed such as a PTW (permit to work).
What are the reasons for isolating supplies from service by the LOTO system?
- Allows maintenance without hazard to maintainers.
2. Isolates equipment that is defective and be danger.
Name the 4 parts of the LOTO (Lock Off/Tag Out) system?
- Log-Off/Tag-Out index sheet.
- LOTO safety certificate.
- Lock-Off/Tag-Out label.
- LOTO- Display board.
What are the 3 MAIN causes of electrical shock?
- Equipment failure (indirect contact)
- Human error (direct contact)
- A combination of both the above.
What is the correct electric shock procedure? (8 marks)
- L.V.A.
- Isolate supply.
- If not able to isolate supply, remove person from supply safely.
(Go on to explain DRSABC)
Before carrying out a LOTO on equipment/system what 3 steps must be carried out?
- Obtain permission from senior rate to carry out isolations.
- All isolation points are to be identified.
- The equipment user is to be informed.
Describe the procedure for removing fuses? (5 marks)
- Place finger in the centre of the fuse holder firmly
- With the free hand unscrew the fuse holder with a fuse key
- When unscrewed firmly grasp the fuse holder turn head away from fuse panel and
remove the fuse holder smartly. - Remove the fuse from the holder and replace the empty fuse holder to maintain a dead front.
- Repeat for second and third fuse way.
Name the dangerous components and their associated hazards found on board HM Ships.
- Tantalum capacitor - subject to certain conditions they may explode, contains sulphuric acid.
- Selenium rectifier - toxic substances are released when they burn out during operation.
- Penetone TPC (not used in HM Submarines)
What precautions are to be taken when using Penetone TPC?
- Flash point of 53* Celsius.
- Keep away from naked flames.
- Supply and exhaust fans to be running.
- Never to be sprayed onto live electrical equipment.
- Shelf life of 12 months.
- Always wear rubber gloves.
What PPE should be worn while working in the galley?
- D.M.S. Boots.
- Overalls or 4’s with sleeves down.
- Chef’s hat.
How are all galley supplies isolated in the event of a fire?
All supplies have isolation switch outside galley. They are all painted red.
What is the biggest fire hazard within the galley?
Deep fat fryer due to high oil temp 180-190 Celsius.
What are the precautions to be taken when working on live electrical equipment?
- Do not take unnecessary risks.
- Wear rubber gloves if possible.
- Use insulated tools.
- Take care not to cause short circuits.
- Wear insulating footwear.
- Be aware of voltages that are, or can be present.
- Do not rely on interlocks or other safety devices.
- Unless essential do not render interlocks or other safety devices inoperative.
- Do not work alone.
- Stand on rubber mats, avoid leaning on bulkheads.
- Work with one hand If possible.
- Check all test equipment is in date.
