Testing

Did you know that at the completion of every addition or alteration to your electrical system, there is a comprehensive set of tests that are mandatory?

Have you seen your electrical contractor spend up to an hour with a meter in their hand – something like this?

Just one type of installation tester that an electrician can use

Mandatory verification process

Section 8 of the Wiring Rules – AS/NZS 3000:2018 – lists s series of tests that all installations, additions and alterations to your electrical system must comply with.

Australian Standard AS/NZS 3017/2007 is currently the document used for guidance on appropriate test methods.

Why is testing important?

Testing of all additions and alterations is important because of a number of factors.

The electrician might have made a mistake and wired up the circuit incorrectly
The cable might have been damaged during installation
The old existing cabling that that has been altered might be faulty
There could be a fault on the switchboard or other associated piece of equipment…
Some part of the installation might not be working properly
etc.

Section 8 of the Wiring Rules

Section 8 of the Wiring Rules is very specific. It is the verification process that all electrical additions and alterations must be tested to comply with. There is no compromise; it either passes, or it fails. There is no grey area an no flexibility.

There are basic checks, and there are comprehensive tests. Basic checks include visual checks, while more comprehensive tests include the Earth Fault Loop test.

So… What are these mandatory tests?

The visual checks:

As this encompasses a vast amount of inspections, it is beyond the scope of this discussion, but one of the critical ones is Earthing. You can see my previous article on earthing found at: https://electricgreg.com/2018/11/18/earthing/

Along with the visual checks, There are six mandatory tests that all electricians must perform.

These are:

Step 1

Visual check – check cabling, switchboard, main earth, bonding, fittings etc. Is it suitable to be connected to the supply?

Step 2

Circuit interconnection
Polarity
Earth Resistance/continuity
Insulation resistance
RCD test – live test
Earth Fault Loop – live test

So what do these tests mean?

1. Circuit interconnection: each circuit must be separated from each other. One circuit cannot be connected in any way to another circuit. If there were interconnections, it is possible that your safety devices might not operate correctly, your RCDs might not operate correctly, or that someone working on your electrical system might be injured or killed.

2. Polarity: The Active must be connected to your active terminals, your Neutral must be connected to the neutral terminal, and your Earth must be connected to your earth terminal. This applies to the connections at the switchboard, and on your fittings/appliances

This might sound simple, but I come across a substantial number of homes where this has been incorrect. The installing electrician didn’t check properly.

3. Earth Resistance/continuity: The resistance of the earth cable and the associated connections must fall within a specific range for your circuit to operate safely. Should the earth resistance be higher than that specified within the Wiring Rules, an injury, death or a fire may result in the event of a fault.

I tested two homes in recent weeks where existing faults were picked up during testing. Neither of those homes had effective earths, which could have resulted in injury or death to the home owner or an occupant.

4. Insulation resistance: The insulation resistance test checks to determine if a cable fault exists. (It can also determine if an appliance fault exists). The insulation resistance is required to be above a specific level for the safe operation of your circuits.

On a new installation, the insulation resistance should be at the highest reading of the insulation tester. On a very old circuit, or a circuit with a heater – water heater, stove, or oven for instance – the insulation resistance would be lower (and acceptable).

5. RCD test: an RCD (Residual Current Device – safety switch) test determines if your RCD is operating within the set parameters. A 30mA test current is applied (in hospitals ore care facilities it is 10mA) to determine if the RCD is operating satisfactorily.

Should the RCD not be tested, and have an unknown fault, in the event of an appliance fault it is possible for injury or death to occur.

6. Earth Fault Loop: This test verifies that the circuit breaker will trip in the event of a fault. Should this test fail, it would indicate that the circuit breaker of fuse might not trip in the event of a circuit (or appliance) fault. This could result in an injury, death or a fire

Earth Fault Loop can be calculated if the length of cable is known, but with modern instruments, the best and safest method is to use a modern test device and test the circuit.

How many electricians actually do these tests?

From my experience of nearly 30 years, not very many… and even less are submitting their mandatory CCEW (Compliance Certificate of Electrical Work).

So… knowing that these tests are mandatory, why aren’t electricians performing all of these tests?

It takes time,
It eats into profits
Clients have to pay more
Electricians can’t compete with those who cut corners – they have to add extra costs for testing and compliance certificates
Electrician’s don’t believe they have made any mistakes, and don’t believe they have to test their work – they therefore believe that they can skip this step.

Nearly every home that I attend, has had electrical work that is NOT compliant – sometimes VERY recent. Tests that I do at the completion of my work, often find existing faults, or they were clearly visible during a basic inspection. This means that electricians are not doing their testing correctly (or don’t care about the quality of work they do).

What does this mean?

Those electricians who are not undertaking their mandatory testing are putting the lives of clients at risk!

They are breaking the law as they are not fulfilling their legal compliance obligations.

Do electrician’s make mistakes?

Yes

Have I made mistakes?

Yes

Have I picked them up during testing?

Yes

That is why we test!

Now that you know that testing is mandatory…

Did the electrician you last used do these mandatory tests?

Did you see him or her carrying around a specialised meter, testing every single light or power point that they installed?

Did they carry out their six mandatory tests, and do a complete visual check of their work? How do you know?

Did your Electrician give you a mandatory compliance certificate for their addition or alteration?

If you answered no to any of these three questions, your electrician has broken the law and you should get them to come back and fulfill their legal obligations.

I guarantee my work complies, and I provide my test results to my client – I am likely one of only a few who do this

I give all of my clients a check list with test results for every single mandatory test. I sign that document and give them a compliance certificate in all instances.

Does yours?

Bye for now, Greg.