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HS&E Operatives practice question: Electrical safety on site (1 of 7)

C. Safety A free question from our original HS&E Operatives practice exam. Try it, then open the answer to see why each option is right or wrong.

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Power tools on site run on 110 volts, from a yellow transformer.

Why is this safer than using 230 volt mains tools?

Choose one answer.

  1. A. If something goes wrong, the shock is much less likely to kill
  2. B. A 110 volt tool can't give you an electric shock at all
  3. C. It means cables never need checking before use
  4. D. It allows the tools to be used in the rain without any risk
Show the answer and explanation

Answer: A

  • A. Right: Right. A 110 volt supply that is centre-tapped to earth means no more than 55 volts between a live wire and earth. A shock is much less likely to be fatal.
  • B. Wrong: Wrong. You can still get a shock from 110 volts. It is just much less dangerous than 230 volts.
  • C. Wrong: Wrong. All cables, plugs and tools still need checking for damage before use.
  • D. Wrong: Wrong. Water still increases the risk. Battery or air tools may be better in very wet conditions.

Explanation

Use battery tools or 110 volt tools on site. A 110 volt centre-tapped supply limits any shock to 55 volts to earth.

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