Electrical Installations Hazards Quiz
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Questions and Answers

If a hazard may lead to an outcome of death or permanent disability, the level of risk is recognized as ____________ and this should be given the ___________ priority.

High, Highest

When implementing measures to control a risk, which of the following control measures should be implemented first?

  • Use Engineering controls to isolate the hazard
  • Use Administrative controls such as written directives or PPE
  • Eliminate the hazard altogether (correct)
  • What should occur as part of your overall risk management process if an incident occurs?

  • Nothing as you have already implemented an approved process
  • Monitor and Review the risk management program for improvements (correct)
  • The following determine the effect of an electric shock on the human body...(You must select all of the correct responses)

    <p>The pathway the current took through the body</p> Signup and view all the answers

    If a low voltage supply can’t be easily isolated, what methods can you use to remove a victim who is suffering from an electric shock?(You must select all of the correct responses)

    <p>Pull them clear by loose clothing</p> Signup and view all the answers

    If a victim is suffering an electric shock from a high voltage installation, you should still attempt to rescue them by pulling or pushing them clear.

    <p>False</p> Signup and view all the answers

    Extra low voltage is regarded as completely safe, as the voltage and current levels are not sufficient to harm persons, livestock or property.

    <p>False</p> Signup and view all the answers

    An RCD is typically designed to trip when 30mA of earth current is detected. If a person was getting an electric shock of 30mA from an RCD protected circuit, the person would experience a shock with the following expected effects.

    <p>A jolt similar to a solid punch with cramping and possible difficulty of breathing</p> Signup and view all the answers

    The heat generated in a cable is determined using the following formula?

    <p>H=I2Rt</p> Signup and view all the answers

    If the current in a cable is doubled, the heat generated will increase by the following amount?

    <p>Four (4) times (quadruple)</p> Signup and view all the answers

    If the current in a cable is tripled, the heat generated will increase by the following amount?

    <p>Nine (9) times</p> Signup and view all the answers

    The maximum continuous current a cable can carry without exceeding its temperature limits is called the..

    <p>Current Carrying Capacity</p> Signup and view all the answers

    With all other things constant, what will happen to the temperature of a cable if the current flowing through it increases?

    <p>The temperature will increase as the power loss (I^2R) in the cable increases</p> Signup and view all the answers

    Wiring systems shall be selected and installed to be suitable for the highest and lowest local ambient temperature. The designated ambient temperature for cable installations in Australia is:

    <p>40oC for installations in air and 25oC for installation underground</p> Signup and view all the answers

    The best installation method for cable entry into a switchboard (from the following) is:

    <p>Cut individual holes for each cable and use cable glands and/or a fire retardant sealant for all free space.</p> Signup and view all the answers

    As an electrician you are called out to the job below. The most likely cause of this fault is:

    <p>A hot joint (high resistance joint) caused by a loose conductor terminal.</p> Signup and view all the answers

    The requirements for recessed luminaires are shown in which clause in AS/NZS 3000?

    <p>Clause 4.5.2.3</p> Signup and view all the answers

    Every permanently connected motor needs an isolation switch so that mechanical maintenance can be carried out when needed.

    <p>True</p> Signup and view all the answers

    Study Notes

    Hazards and Risks in Electrical Installations

    • A hazard leading to death or permanent disability is classified as High Risk, requiring the Highest Priority attention.
    • The first control measure to implement for a risk is to eliminate the hazard altogether.
    • After an incident, the risk management process should include monitoring and reviewing for improvements.
    • The effects of electric shock on the human body depend on the following factors:
      • Duration of the shock
      • Amount of current flowing through the body
      • Pathway taken by the current through the body

    Electric Shock Response

    • For low voltage supply incidents, safe removal methods include:
      • Kicking the victim clear with the sole of your boots
      • Pulling them clear using loose clothing
    • Attempting to rescue a victim from high voltage should be approached with caution; it is deemed False to say you should rescue by physical means due to the high risk.

    Current and Electric Shock Effects

    • Extra low voltage is not regarded as completely safe; dangers still exist.
    • An RCD (Residual Current Device) typically trips at 30mA of earth current, which can cause:
      • Jolt similar to being punched, with cramping and possible breathing difficulties.

    Electrical Properties and Formulas

    • The formula for heat generated in a cable is H = I²Rt.
    • If the current is doubled, heat generated increases by four times; if tripled, the increase is nine times.
    • Current Carrying Capacity refers to the maximum continuous current a cable can handle without overheating.
    • Increasing current through a cable leads to a rise in temperature, due to power loss (I²R) in the cable.

    Installation Standards

    • The designated ambient temperature for cable installations in Australia is:
      • 40°C for installations in air and 25°C for underground installations.
    • Best installation method for cable entry into a switchboard requires cutting individual holes with cable glands or fire retardant sealant for proper sealing.

    Fault Diagnosis and Regulations

    • Common causes of electrical faults include short circuits and high resistance joints.
    • The requirements for recessed luminaires are specified in Clause 4.5.2.3 of AS/NZS 3000.
    • Every permanently connected motor must have an isolation switch to facilitate maintenance safely.

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    Description

    Test your knowledge on hazards and risks associated with electrical installations. This quiz covers various important aspects of safety and protection in electrical systems. Ensure you're well-prepared to manage risks effectively.

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