Saturday, April 5, 2008

Typical Examination Questions based on Element 6

1.

a) Describe
the possible effects of electricity on the body.

b) Outline FOUR factors that may affect the severity of injury from contact with electricity.

(4)


(4)

  1. Affects such as interference with nerve/muscle action, tissue burns and cardio-respiratory effects, in particular the risk of fatal injury due to disruption of heart rhythm. As far as tissue burns are concerned, candidates should have identified as the main sites of damage the entry and exit points and warned of the possibility of damage to internal organs. Better responses included reference to secondary injuries such as head injuries caused by falls following electric shock.
  2. Factors such as the voltages involved the length of contact time, the route taken through the body, and the general health and age of the person involved. Additional factors that might affect the severity of the injury include the dryness of the skin, natural body resistance, ground conditions and the type of footwear being worn at the time.

2.

Outline
the measures to be taken to minimize the risk of shock from the use of electric hand tools.

(8)

Measures include:

  • The use of reduced low voltage trough a transformer centre-tapped to earth
  • The use of residual current devices or earth leakage protection.
  • The protection and safe positioning of supply cables
  • Using double-insulated equipment
  • Using cordless (battery operated) equipment
  • Ensuring the correct rating of fuses
  • Introducing a system for routine visual inspection and testing of cables and equipment

3.

HSG65 Electricity at Work-Safe Working Practices gives guidance on the frequency of inspection for such equipment.

State frequencies for the inspection and testing of electrical hand held tools and associate equipment used on a construction site and support your answers with appropriate examples.


(8)

A hand held tool and equipment should be visually inspected before use, including cables, cord grips, casings and plugs.

230 volt equipment should be tested before first use and then at monthly intervals while a formal weekly inspection is also required.

110 volt equipment should be tested before first use and then at three monthly intervals while a formal monthly inspection is also required.

Extension leads should have an initial test before first use followed and then at monthly intervals while a formal weekly inspection is also required

4.

List
the items that should be included on an inspection checklist designed to ensure the safety of portable electrical hand-tools.

(8)

Items on list could include: Equipment appropriate for the task and environment, equipment tested, plugs, connectors and cables free from damage or defect, correct wiring and sound connections, fuses and other means of preventing excess current in place and of correct rating, accessibility and appropriate means of isolation and system not overloaded.



5.

In relation to the use of electrical cables and plugs in the workplace:


(i) Identify FOUR
examples of faults and bad practice that could contribute to electrical accidents.

(ii) Outline
the corresponding precautions that should be taken for each of the examples identified in (i).



(4)


(4)

Examples include: Failure to select right equipment for the environment (armoured or heat resistant cables may be require). Incorrect rating of fuses. Ineffective or discontinuous earthing. Overload of Socket outlets. Cables unnecessarily long (or too short). The use of coiled extension leads. Poorly wired plugs (wires under tension or outer protective sheath not clamped). The use of defective cables and plugs.

(ii) Precautions should have followed automatically from the deficiencies listed in (i)

1 comment:

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