Are you using the right safety switch?

Selecting and installing a suitable safety switch for equipment on a circuit is the responsibility of electrical contractors.

According to the Queensland Electrical Safety Office, 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, then the electrical contractor has not met their duties under the Electrical Safety Act 2002 and you will face enforcement action.

When you select a safety switch, contractors 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, the Electrical Safety Office said that contractors may need to consider using a Type A, Type F or Type B safety switch. Which one is chosen 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.

According to the Electrical Safety Office, 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 on requirements for safety switch type selection can be found in:

• AS/NZS 3000:2018 section 2.6.2.2.1
• AS/NZS 3000:2018 section 4.12.5.2.2
• AS/NZS 3000:2018 section 7.3.5.2.2
• AS/NZS 4777.1:2016 section 5.4.4
   

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