If your business requires fault loop impedance, otherwise known as Earth fault loop impedance, you’ll have to comply with the requirements of Standard AS/NZS 3000 Wiring Rules so that the design, safety measures, and installation and testing of electrical equipment is up to code.
How Earth Fault Loop Impedance Works
There are essentially four components within a system for measuring and taking earth fault loop impedance into account to ensure safety standards are met.
The protective earthing conductor (otherwise known as the “PE”). When performing an earth fault loop impedance calculation, the ultimate objective is to determine the appropriate earth cable size
2. The neutral return path, containing a neutral conductor (“N”) between the location of the primary neutral terminal, and the neutral transformer point’s location.
3. The current’s way across the transformer winding.
4. The location of the active conductor (“A”) to the point of the fault.
Technicians like those employed by Jim’s Test and Tag intimately understand how all this fits together, and they are prepared to help you calculate the proper earthing cable size, so you can be sure that your protective measures work properly to prevent indirect contact with live wires, which can cause serious injuries if they lead to electrical shock.
Regulatory Requirements
One of the most basic requirements of AS/NZS 3000 and similar standards, as put into legal effect by statutes in both Australia and New Zealand, is protecting workers exposed to these wires from what is referred to as “indirect contact” with the live parts of the wiring system. In most cases, automatically disconnection of the power supply, as with a residual current device, is the standard way of dealing with this requirement. But that’s not all.
The disconnection period must be extremely short, and the wiring rules specify how long each circuit can be designed to stay on before automatic disconnection occurs after a current leakage event. A short-circuit of negligible impedance can occur between the active and protective conductors, or any other directly exposed conductive components of the electrical system. RCDs or Residual Current Devices often satisfy this requirement, but they themselves require significant amounts of testing and maintenance both to remain effective and to meet the regulatory requirements as formulated in the Standard AS/NZS 3000.
Here’s the most important part: the impedance of the fault current path (otherwise known, especially within the Wiring Rules, as the fault loop impedance path) must remain sufficiently low to provide for enough current flow to make certain that the protective device can function within a specified time limit.
Why Jim’s Test and Tag
The professional technicians from Jim’s Test and Tag can help you ensure the proper size for your earth wire cables, so that the proper requirements for earth fault impedance are met, satisfying both AS/NZS 3000 and the general standards of a safe and healthy workplace. Don’t let your desire to keep things cost-efficient and in-house deter you from taking the proper precautions, either: bringing in an outside company like Jim’s Test and Tag ensures both that you get the highest level of industry expertise and a genuine commitment to safety, and that you get it at a reasonable price that takes your bottom line into account.
