New clause preventing electric shock in Commercial Buildings
Effective January 1st, 2019 was the new edition of the AS/NZS 3000 Wiring Rules Standard (Electrical Installations), which outlined over 200 changes and expanded upon the coverage of electrical installations. The changes have taken into account new technologies, new products and improvements in safety, whist clarifying on the previous versions ambiguous requirements.
One of the major changes to the AS/NZS 3000: 2018 is the mandatory Residual Current Devices (RCD) requirements for the protection of sub-circuits and relating alterations and repairs (clause 188.8.131.52.3).
Everyone in the industry is bound by them and every customer is the beneficiary.
In commercial and industrial environments, the RCD requirements for final sub-circuits has increased to 32 Amp, from the previous 20 Amp to provide personal protection from electric shock to the following circuits:
- power circuits for socket outlets (1, 2 & 3 Phase)
- lighting circuits
- directly connected handheld equipment
- directly connected stationary equipment within a high risk area.
All other final sub-circuits not in excess of 32 Amp are to be assessed RCD compatible and if so should be RCD protected to ensure they are both safe and compliant.
The purpose of the mandatory clause is to essentially minimise the risk of electric shock. When determining what an increased risk of electric shock is, we take into consideration the electrical equipment or appliance being used (e.g. is the electrical equipment Class 1, exposed conductive parts), external influences (e.g. exposure to elements, vibration, production line) and the connection to the supply.
There are exceptions however, one being applied where the equipment has leakage current that would impair on its reliable operation. This scenario would require a risk assessed appropriate alternative method of installation and equipment selection would be needed to achieve the same level as RCD protection; this could include additional mechanical protection, a separated supply or earth monitoring protection.
Even though the new standard calls for RCDs on all sub-circuits up to and including 32 Amp, exemptions can be applied for when:
- sub-circuits supply power to specialised equipment
- the equipment develops a fault where a greater danger exists than leakage current
- the equipment operating under normal conditions has the ability to produce earth leakage of a level that will trip a 30 Amp RCD
- a single item of electrical equipment (e.g. a socket-outlet or light) which is not RCD-protected is replaced with an equivalent item in the same location – like for like
- the reliability of the equipment is essential to the business operation.
The common complaint of nuisance tripping is not a valid reason for an exemption.
Comply with the Standards, it could save someone’s life, including yours.
What are the requirements for RCDs with alterations or replacement to switchboards?
RCD requirements are applicable when switchboards are altered or replaced. In an alteration, RCDs are required for final sub-circuits. RCDs are also required to protect power-outlets when added to an existing circuit (in accordance with the requirements for new sub-circuits, in the part of the installation in which they are located).
Where power-outlets are being added to an existing circuit and RCD protection is required, the RCD protection is only required to be fitted at the origin of the additional wiring. Where all circuit protection on a switchboard is replaced, additional protection by RCDs are required for the final sub-circuits supplied by that board.
As a Facility Manager, what do these changes mean for you?
The cost of installing new circuits for additional electrical equipment will be substantially higher, with the inclusion of RCDs. Be prepared for an increase in costs for additional circuits (especially 3 Phase), which may lead to the requirements for a switchboard upgrade, in order to facilitate the installation of the RCDs.
As commercial and industrial electrical contractors, it’s important that we are across all of the changes for our clients, awareness and safety are paramount.
Alex Lamblin – Director
For advice and assessment on your commercial and industrial electrical requirements call Prolux on 1800 800 880.