Electrical hazards

Lesson Progress:
  • There may be overhead power lines on site, which are only completely safe if isolated by a competent and authorised person.
  • People have been electrocuted and killed when items (such as ladders, towers or mobile plant) accidently touch or come close to live or charged overhead power lines. Remember, objects only need to be close to the cables, not actually touching them, for electricity to jump (arc) and electrocute you.
  • Burns, scorch marks or burning odours indicate an electrical fault.
  • Damaged leads and cables, even if it is just the outer sheathing, must be taken out of use.
  • If you see smoke from a power tool, switch it off and take it out of use.
  • If a fuse blows, it means there is a fault. Switch off and disconnect the equipment and report it to your manager. Do not try to do any repairs (even changing a fuse), unless you are trained, competent and authorised to do so.

Protection devices

  • Residual current devices (RCDs) work by cutting the power quickly if there is a fault.
  • Portable RCDs fit between the plug and the socket.
  • They must be kept free of moisture and dirt and protected against vibration and mechanical damage.
  • Your site rules may require you to use a RCD with any 230 volt tool.
  • Portable RCDs should have a combined inspection and test before first use and then every month.
  • Portable RCD units should have a mechanical (trip) test before each use. You do this by pressing the test/trip button.

Portable appliance testing

  • HSE guidance recommends that tools, leads and equipment should be tested every three months if used on site.
  • If used, the portable appliance testing (PAT) label will tell you when the last safety test was carried out. It does not tell you when the next test is due.