Exams / HS&E MAP / Electrical safety / Question 2
HS&E MAP practice question: Electrical safety (2 of 4)
C. General safety A free question from our original HS&E MAP practice exam. Try it, then open the answer to see why each option is right or wrong.
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You are planning the temporary electrical supply for a site.
Which supply voltage does HSE recommend for portable tools?
Choose one answer.
- AA. 400 volts, so tools are more powerful
- BB. Any voltage, as long as there is an RCD
- CC. 110 volts, centre-tapped to earth
- DD. 230 volts, as it is the same as at home
Show the answer and explanation
Answer: C
- A. Wrong: Wrong. Higher voltage means greater shock risk.
- B. Wrong: Wrong. RCDs are a back-up. Reduced voltage is the main control.
- C. Right: Right. HSE recommends 110 volt centre-tapped to earth supplies on construction sites, as a shock is much less likely to kill.
- D. Wrong: Wrong. 230 volts is more dangerous on a construction site.
Explanation
Use 110 volt centre-tapped to earth supplies, or battery tools, on site. Use RCDs as a back-up where 230 volts is needed.
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