Wiring rules for ELV downlights
Incorrect wiring and installation of extra low voltage (ELV) downlights can result in electric shocks and injuries. The heat produced by ELV downlights can also ignite nearby combustible material such as roof insulation and building material causing fires.
Australian standard AS/NZS 3000 outlines installation rules for electricians installing extra low voltage (ELV) downlights. The wiring of ELV downlights must comply with the requirements of the standard to ensure the safety of the installation.
Selecting and installing electrical equipment
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, and
- not cause 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
- be installed in accordance with the manufacturer's instructions.
A wiring system shall be selected and installed so as to minimise the risk of mechanical damage. This shall be provided by one or any combination of the following:
- mechanical characteristics of the wiring system
- location selected
- provision of additional local or general mechanical protection.
Mechanical stress on electrical connections
All cables and conductors shall be installed so that there is no undue mechanical stress on any connections.
Recessed luminaires and their ancillary equipment shall be installed in a manner designed to minimise temperature rise and prevent the risk of fire. The temperature rise at the rear of a recessed luminaire shall be limited to prevent damage to adjacent materials.
This requirement shall be satisfied by one of the following methods:
- using a luminaire that is certified by the manufacturer to contact or be enclosed in combustible material or thermal insulation
- installing a suitable fire resistant barrier that is classified in compliance with AS/NZS 5110.
- provision of the required clearance distances as specified by the manufacturer of the luminaire
- provision of the default clearance distances as described in AS/NZS 3000.
Recessed luminaires and their auxiliary equipment shall be installed in such a manner that necessary cooling air movement through and around the luminaire is not impaired by thermal insulation or other material.
Where thermal insulation is of a type that is not fixed in position – eg loose fill insulation – a barrier or guard constructed of fire resistant material shall be provided and secured in position to maintain the necessary clearance.
Where thermal insulation may reasonably be expected to be installed in the space containing a recessed luminaire, the luminaire shall be installed in such a manner as to provide for the subsequent installation of the thermal insulation.
Recessed luminaires should be installed with protective measures to guard against the collection of combustible materials such as leaves, vermin and debris.