Heat pump installations for electrical work

Purpose

The purpose of this advisory note is to inform industry of some common non-compliances found when Building Commission NSW inspectors conduct inspections of Heat Pump Hot Water installations.

Issue

Heat pump hot water installation

Reference

2.6.3.2 of AS/NZS 3000:2018 - Electrical installations

Details of non-compliance 1

The Heat Pump Hot Water system was not protected at the supply by a residual current device.

During inspections, it was noted that many installations lacked the required residual current devices (RCDs). Under Clause 2.6.3.2 of AS/NZS 3000:2018, RCD protection is mandatory for all electrical circuits to mitigate electric shock risks. Without RCDs, the safety of users is severely compromised, as the device is designed to disconnect supply in the event of a fault, such as insulation failure or accidental contact with live parts.

Note: In Australia the use if Type AC RCD’s is no longer permitted for installation. Type A RCD’s can be identified by the dual sign wave printed on the RCD.

How to comply

AS/NZS 3000 Wiring Rules

When installing a new circuit for a heat pump hot water system or upgrading an existing hot water system to a heat pump system, a Type A RCD shall be used/upgraded as the circuit protect device.

As per AS/NZS 3000:2018 2.6.3.2.2.

Additional protection by RCDs with a maximum rated residual current of 30 mA shall be provided for all final subcircuits in domestic and residential electrical installations.

As per AS/NZS 3000:2018 2.6.3.2.3.

Additional protection by RCDs with a maximum rated residual current of 30 mA shall be provided for all final subcircuits in domestic and residential electrical installations.

Details of non-compliance 2

The Heat Pump Hot Water system was not provided with a local isolating device.

Several installations did not include a local isolator for the new hot water systems. Clause 4.19.1.1 of AS/NZS 3000:2018 requires a local means of isolation to ensure safe maintenance and servicing of equipment. The absence of a local isolator increases the risk to technicians who may inadvertently work on live circuits, leading to potential electric shock or injury.

Note: Where multiple hot water systems are installed, each individual unit should have its own isolating device installed locally to the unit.

How to comply

AS/NZS 3000 Wiring Rules

Where a Hot Water System is direct connected, an isolating device shall be used for local isolation of the system, the device must be able to be locked in the off position when the system is being worked on. 

As per AS/NZS 3000:2018 4.8.2.3

Every water heater that is direct connected shall be provided with an independent, isolating switch (lockable) in accordance with Clause 2.3.2.2.

The isolating switch shall be:

• additional to any automatic switch incorporated in the heater structure; and
• installed adjacent to but not on the water heater.

Where a water heater is supplied by two or more final subcircuits, all of the final subcircuits for that water heater shall be capable of being isolated by a single isolating switch.

Details of non-compliance 3

The wiring system were not installed in manner to prevent the ingress of water or moisture.

The conduit work at several sites was not installed correctly or made watertight, contrary to Clause 3.3.2.3 of AS/NZS 3000:2018, which mandates weatherproofing for exposed electrical wiring systems. Non-compliant conduits can allow water ingress, leading to corrosion, short circuits, or electric shock hazards, particularly in outdoor installations exposed to weather conditions.

Note: Where a wiring system connects to devices that contain electrical components a sealing compound can be used to prevent loosening of the wiring system preventing potential ingress of water, moisture and foreign objects.

How to comply

AS/NZS 3000 Wiring Rules

Where a wiring system is used in a outdoor environment it shall be able to prevent the ingress of water or moisture which could cause the system to fail. 

As per AS/NZS 3000:2018 3.3.2.3

Wiring systems shall be selected and installed so that high humidity or the entry of water does not cause damage.

Where water may collect or condensation may form in a wiring system, to the extent that it creates a hazard, provision shall be made for its harmless escape through suitably located drainage points.

Where a wiring system may be subjected to wave action (water), protection against excessive flexing and mechanical damage shall be provided in accordance with Clauses 3.3.2.6, 3.3.2.7 and 3.3.2.8.

Details of non-compliance 4

The outdoor condenser unit was installed in a position which prevents the unit form performing its function in line with manufacturers requirements.

Instances were identified where outdoor condenser units were installed indoors, contravening the manufacturer's installation guidelines and AS/NZS 3000:2018 Clause 1.7.1, which emphasises compliance with equipment instructions. Indoor installation of outdoor units can lead to inadequate ventilation, reduced efficiency, and overheating, creating potential fire hazards and equipment failure.

Note: Lack of airflow around the condenser units cause the unit to overheat and not efficiently produce hot water.

How to comply

AS/NZS 3000 Wiring Rules

Electrical equipment must be installed in a manner for it to operate in a reliable manner and not pose potential risk to person or property.

As per AS/NZS 3000:2018 1.7.1

Electrical equipment forming part of an electrical installation shall be:

• selected and installed to operate in a safe and reliable manner in the course of normal operating conditions;
• selected and installed so as not to cause a danger from electric shock, fire, high temperature or physical injury in the event of reasonably expected conditions of abnormal operation, overload, fault or external influences that may apply in the electrical installation; and
• electrical equipment shall be installed in accordance with the requirements of this Standard and the additional requirements as specified in the manufacturer’s instructions.