Choose the right safety switch for the job

Electrical contractors are responsible for selecting and installing a suitable safety switch for the equipment connected to the circuit.

Installing an incorrect safety switch type or installing fixed equipment without checking if the safety switch on the circuit is suitable, may leave the electrical installation unsafe. If this occurs, you as the electrical contractor, have not met your duties under the Electrical Safety Act 2002 and you will face enforcement action.

When you select a safety switch you must consider:

• the current waveform and possible waveform of fault current to earth
• the different types available (Type A, Type AC, Type F or Type B)
• the electrical equipment to be connected to the circuit
• whether it meets the requirements specified by the equipment manufacturer.

AS/NZS 3000 indicates, where required, the installer must seek guidance from equipment manufacturers to ensure a suitable safety switch type is installed.

Rather than installing the minimum requirement, Type AC safety switch, you may need to consider using a Type A, Type F or Type B safety switch. Which one you choose will depend on the electrical equipment to be connected to the circuit and requirements specified by the equipment manufacturer.

For general use power circuits, it is recommended that Type A safety switches be used (in place of the minimum type AC required by AS/NZS 3000) to accommodate the connection of electronics-based equipment. Where lighting circuits use electronics-based equipment (such as LED lighting or electronic speed-controlled ceiling fans) then type A safety switches are also recommended.

The most common installations where an incorrect safety switch has been installed are solar PV inverters, battery storage inverters, uninterruptible power supply systems and power electronics-based loads (such as variable speed motor drives).

Further information

Further information on requirements for safety switch type selection can be found in:

1. AS/NZS 3000:2018 section 2.6.2.2.1
2. AS/NZS 3000:2018 section 4.12.5.2.2
3. AS/NZS 3000:2018 section 7.3.5.2.2
4. AS/NZS 4777.1:2016 section 5.4.4

For more information on your electrical contractor duties, visit WorkSafe.qld.gov.au