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Electrical Tests -

Electrical testing of portable equipment will usually involve the following:-

  • Earth Bond Testing
  • Insulation Tests

Other tests which may be carried out include:-

  • Load Testing
  • Earth Leakage Test
  • Polarity and Fuse checks
  • Flash Testing

Earth Bond Test (Class 1 equipment only)

In order to test that the earth bond is sound, a current of at least 1.5 times the plug fuse rating is passed through the earth bond circuit for a period of approximately 5 seconds.

Readings should show less than 0.1+R Ohms (where R is the resistance of the lead)

If there is a risk that the high current described above might cause damage, an alternative test may be carried out using a low current of between 20mA and 200mA (usually a current of 100mA is used.)

Insulation Resistance Test

The applied test voltage should be approximately 500 Vdc

  • Class 1 heating equipment < 3kW, 0.3M Ohms
  • Class 1 All other equipment 1M Ohms
  • Class 2 Equipment 2M Ohms
  • Class 3 Equipment 250k Ohms

Optional Tests

Flash Test: No flashover or breakdown shall occur

Operation/Load test: Compare reading with stated details on nameplate

Earth leakage test:
Class 1 Handheld Appliances 0.75mA
Other Class 1 Appliances 3.5mA
Class 2 Appliances 0.25mA

Note that the Earth Leakage Test is now normally referred to as the Touch Current Test. Some testers offer a Substitue Leakage or Substitute Touch Current Test which aims to carry out the same test but with reduced voltage.

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