The Problem

Electrical energy is energy that exists as a result of moving electric charges, where the faster electric charges move, the more electric energy they store (Soft Schools 2016). Within Australia, the risks associated with electrical energy caused around 15 deaths a year from 2003 – 2008 and 91 emergency hospital admission from work-related electrical injuries from 2002 – 2004. Furthermore, from 2006 – 2007, 190 claims relating to contact with electricity were made, with five being fatalities, and 70% of claims serious enough to result in at least two weeks of absence from work (Ruschena 2012). In particular, interactions with electricity can result in electrical burns where an electrical current passing through a body heats tissue located along the length of the current flow, as well as thermal burns where being too close to heat caused by electricity results in a burn. Of course, one of the most common dangers of interacting with electricity are electric shocks, whereby being shocked can cause (along with burns) cardiac arrest, prevention of breathing, and muscle spasms. In a case where an electric shock has caused death, it is then referred to as electrocution (Health and Safety Executives 2016).

 

The Underpinning Science

The production of electricity includes a flow of electrons through a conductor caused by an electromotive force. An electric current refers to the movement of electric charges, while amperes (amps) are used to measure the intensity of an electrical current. The electromotive force causes the current to flow, whereby for a conductor of electricity, a higher voltage will mean a higher current flow (Ruschena 2012). Interestingly, while one would believe that 100,000 volts is more dangerous than 100 volts, this is not the case. In fact the danger of electricity, particularly with shocks lies within the electrical current (amps) forced through the body (Giovinazzo 1987).

 

Hazardous Situations

There are many situations where electricity can become a hazard. Some of these include:

  • Exposed electrical parts
  • Inadequate/poor wiring
  • Damaged insulation
  • Overloaded circuits (shown in Figure 1)
  • Wet conditions

(United State Department of Labor 2016)

All of the hazardous situations listed can lead to a fire or someone being shocked, which can ultimately mean being burned, obtaining muscle damage, or even dying as a result. Electrical injuries occurring as a result of these types of hazards occur most frequently in manufacturing, retail and construction, while a very small amount occur in the actual electricity, gas and water industries (Ruschena 2012).

Figure 1: A hazardous overloaded circuit

curcuit.jpg

(JP Electric 2016)

Measurements and Evaluation

The impact that contact with an electric current can have varies from person to person due to size and gender. Regardless of this however, there are certain measurements which define the expected outcome of an interaction with certain amounts of amps. This includes:

  • 0.001 – 0.01 amps: mild sensation
  • 0.01 – 0.1 amps: severe shock (painful shock, unable to easily let go of conductor, muscular paralysis, breathing difficulties)
  • 0.1 – 0.2 amps: death
  • 0.2 – 1.0 amps: severe burns and no breathing

(Giovinazzo 1987).

As it can be see, death occurs between 0.1 and 0.2 amps, but not necessary for 0.2 amps or more. This is because muscular contractions are so severe that the heart forcibly clamps during a shock that is this intense. The clamping of the heart prevents ventricular fibrillation from occurring which means that the chances of survival are fairly positive for a person who experiences a shock of this intensity (Giovinazzo 1987). It is important to note however that the presence of moisture such as wet clothes, as well as metal such as watches will increase the severity of a shock (Giovinazzo 1987).

 

Safety Strategies

Legislation and Standards

  • Electrical Safety Act 2002
  • Electrical Safety Regulation 2013
  • Australian Electrical Standards
  • Wiring Rules clause 4.5.2.3
  • Work Health and Safety Regulations (WHS) – requires anyone conducting or undertaking a business must ensure a work environment without risks to health and safety, which means they should follow the legislation, regulations and standards mentioned above in order to do so
  • AS/NZS 2210.1:2010 – requires certain footwear to be worn
  • AS 2225–1994 – requires certain gloves to be worn
  • The draft national WHS s 4.7.13 –  prohibits work on electrical apparatuses while the equipment is energised except in specified circumstances

(WorkCover Queensland 2016 ; Ruschena 2012).

Control Measures

  • Ensure electrical circuits are not accessible through location (such as powerlines being elevate high to avoid contact with them)
  • Use of circuit breakers and residual current devices as part of electrical circuits to protect against electrical faults
  • Use of maintenance records, diagrams of designs, and plant and equipment records
  • Wearing personal protective gear as shown in Figure 2, such as insulted glove, safety footwear, and work clothes that are made of natural fibres such as cotton or wool, or clothing that is made of treated/formulated synthetics

(Ruschena 2012)

Figure 2: Appropriate safety clothing for electrical work

safety clothes.jpg

(Electrical Engineering Portal 2012)

 

References

Electrical Engineering Portal 2012, 21 safety rules for working with electrical equipment, viewed 9 June  2016,  http://electrical-engineering-portal.com/21-safety-rules-for-working-with-electrical-equipment

Giovinazzo, P 1987, The fatal current, viewed 9 June 2016, https://www.physics.ohio-state.edu/~p616/safety/fatal_current.html

Health and Safety Executives 2016, Electrical injuries, viewed 9 June 2016, http://www.hse.gov.uk/electricity/injuries.htm

JP Electric 2016, Spring energy saving tips, viewed June 9 2016, http://jpelectric.com/category/electrical-maintenance

Ruschena, LJ 2012, ‘Physical hazards: Electricity’, OHS Body of Knowledge, viewed 9 June 2016, http://www.ohsbok.org.au/wp-content/uploads/2013/12/23-Hazard-Electricity.pdf?d06074

Soft Schools 2016, Electrical energy examples, viewed 9 June 2016, http://www.softschools.com/examples/science/electrical_energy_examples/20/

United State Department of Labor 2016, Big four construction hazards: Electrical hazards, viewed 6 June 2016, https://www.osha.gov/dte/grant_materials/fy08/sh-17792-08/electrical_english_r6.pdf

WorkCover Queensland 2016, Electrical safety laws, viewed 9 June 2016, https://www.worksafe.qld.gov.au/laws-and-compliance/electrical-safety-laws

 

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