TYPES OF TEST

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Just like in everything we do, there is a right and wrong way to test appliances. You can get ‘real’, straight-forward and easy to read information from the Standard AS/NZS3760:2010/2022 which covers not only how to test but also the environment for frequency of inspection and testing which is now based around usage rather than being specific site based. Testing can be quick and easy if you have good equipment and the right training.

Class I Equipment
Safety Class I electrical equipment is electrical equipment that relies on the Protective Earth and basic or single insulation for its safety – such items usually have quite a lot of exposed metal and are often quite heavy, although this is not always the case. Some examples of Class I equipment could be dishwashers/washing machines/irons/fridges/ electrical machinery/drill presses/saw benches/bench grinder etc.

This type of appliance is often referred to as an ‘earthed’ appliance
Class II Equipment
Safety Class II electrical equipment relies on two layers of insulation, many times reinforced insulation will replace the two layers of insulation, but the reinforced insulation will be equivalent to the two layers of insulation.

This type of appliance is often referred to as a ‘double insulated’ appliance

It will normally be marked with the doublebox symbol
RCD (Residual Current Device)
Isolation Transformer
This is used for increasing electrical safety and is designed so that the two sets of windings (the primary and secondary) are separated from each other by at least the equivalent of that required to achieve double insulation, thereby ensuring that the electricity from the secondary (output) side is isolated from earth.
EPOD (Electrical Portable Outlet Device)
How to carry out the testing:
The Visual Inspection (this test is carried out on all types of equipment)

This is very important as approximately 90% of faults can be found by this inspection alone.The Visual Inspection is not just an inspection, it basically is‘everything but’what is done during the actual electrical testing process. This part of the testing process may involve:

Smelling

Pulling on leads

Tapping the appliance

Shaking

Turning some part/s

Checking by trying to see that retractable guards actually retract… and all manner of other things may be done to ensure that it is safe to operate.

For Class I (earthed) equipment
Earth Continuity Test – this may be done with an Ohm Meter or a Portable Appliance Tester (PAT). The Standard AS/NZS3760: 2010 suggests a test current for PATs of 100mA to 25 Amps.

Insulation Test/Leakage Test – a leakage test shall be done on appliances that have internal switching that is only activated when the equipment under test is powered at operating voltage. For equipment that does not have internal switching as above then a 500 Volt insulation test is an acceptable alternative.
For Class II (double insulated) equipment
Insulation Test/Leakage Test – a leakage test shall be done on appliances that have internal switching that is only activated when the equipment under test is powered at operating voltage. For equipment that does not have internal switching as above then a 500 Volt insulation test is an acceptable alternative.
For Cord Extension Sets
For RCDs
Earth Continuity Test

Insulation Test/Leakage Test

Trip Time Test – in addition to the above tests RCDs shall have a trip time test performed on them at the time period specified in Table 4 AS/NZS3760: 2010

Legally it is a requirement – but is it really necessary? Potentially the most dangerous appliances are Class I appliances (earthed appliances) eg microwave ovens/bench grinders and the like, but also in this category are extension leads.

Class I appliances are designed to have an earth – this means that in the example of the floor polisher the body of the polisher is connected to earth – literally to the ground via an earth conductor which goes right back to the building switchboard and then into the ground the building is sitting on. If this conductor is damaged anywhere then the consequences can be fatal – this has been explained in greater detail below. It is obvious therefore that the conductor needs to be tested.

The difference between using a Multimeter and a PAT Tester with a high current earth bond capability is that a Multimeter does a Continuity Test where as a PAT Tester does an Earth Bond or Earth Integrity Test.

There is a VERY BIG DIFFERENCE between the two tests.

Unfortunately, most people believe they are carrying out the testing properly if they are using a Multimeter or an Insulation Tester, but these types of instruments will not usually pick up an earth fault unless there is a complete break in the conductor.

There is another type of tester available on the market that people, including many electricians, may not be aware of – it is called a Portable Appliance Tester or ‘PAT’ for short. The PAT is specifically designed to test electrical safety and does all the different tests necessary to ensure the electrical safety of the appliance and makes testing easy.

It is very important to first ensure that the Earth is satisfactory before undertaking the Insulation Resistance Test

To see the difference between testing with a Multimeter or an Insulation Tester compared with a suitable Portable Appliance Tester (PAT), try doing this simple test:

In these two diagrams the battery charger represents a PAT Tester, something that produces a low voltage high current electrical supply. The 10 amp fuse in both cases represents the last remaining strand of a multi-core earth wire.

TYPES OF TEST

Get Your Equipment Certified By Our Test & Tag Technicians

Let’s look at what these words (together with a few other common terms) mean:

The Visual Inspection (this test is carried out on all types of equipment)

Then depending on whether the equipment is Class I or Class II the following tests are done:

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