AS/NZS 3000: 2018 Wiring Rules Standard for RCDs in Commercial Buildings

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 2.6.3.2.3).

 

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.

Major benefits for installing Retrofit Air Circuit Breakers into switchboards

In building maintenance, seeking regular routine electrical inspections for industrial or commercial switchboards is of high importance. Thermal imaging or thermographic scanning by an electrician is recommended every six months, and having existing switchboards fitted with retrofit air circuit breakers (ACBs) is now also proving to be an invaluable process for building owners and facility managers.

Air circuit breakers are commonly used in low voltage switchboards and due to their typically passive operation, are often forgotten about until there is a trip or circuit breaker failure, leading to a disruption in the power supply. Whilst circuit breakers may remain inactive for many years, they may be called into operation at any time, as their main role is to prevent damage to the installation from various forms of overcurrent.

Rectifying improbable issues and correcting possible faults before they arise is invaluable, saving on loss of productivity, downtime, danger to personnel and in many cases, exuberant costs, all which could have been avoided if the problem had been identified earlier. Rather than replacing a low voltage switchboard which causes severe disruption on operations and tenants, or an entire air circuit breaker and its components, there is now the option to retrofit the circuit breaker only.

What are the benefits of Retrofitting a low voltage switchboard?

Many of today’s low voltage industrial and commercial switchboards, are protected by air circuit breakers that have been in operation for decades, some for fifty years. Any circuit breaker that’s been in service for such a time period will either be very close to the end of its working life or at worst, beyond it. It is important to remember, that low voltage circuit breakers are in fact safety devices. They must be in working order and provide protection when called upon.

A proactive approach to system protection includes routine commercial and industrial electrical maintenance, however, as aging breakers become obsolete, this may be insufficient to satisfy tenants needs such as improving the electrical and mechanical performances, extending the life of the system or complying with safety regulations. As production or process requirements change and as safety codes and standards become more stringent, it is important to ensure coordination and protection within the system.

A dilemma faced by facilities managers is ensuring planned production downtime is kept to a minimum and essential components like air circuit breakers don’t fail without notice. A solution is to install retrofit air circuit breakers. This allows end users to modernise their air circuit breakers without compromising on downtime, along with the added benefit of increased cost savings compared with major alterations to an entire switchboard. The key components of the system can be quickly replaced during routine air circuit breaker maintenance, leaving the current copper busbars and steelwork intact.

When air circuit breakers fail, building and facility managers have a decision to make:

  • replace the switchboard
  • repair the faulty circuit breaker or
  • retrofit the circuit breaker with a new, modern air circuit breaker.

Retrofit air circuit breakers provide much less disruption and downtime and are far cheaper than the other options. Put simply, a switchboard is a large metal box that contains circuit breakers, which are connected by copper busbars. If power is properly maintained to the required standard, the only part of the switchboard that can drastically fail is the air circuit breaker. So you may think “why not just replace the circuit breaker?” When the existing air circuit breaker is replaced with a modern version the chassis has to stripped out and copper busbars have to be modified to suit the switchboard on-site. This process can be a perfectly fine solution, however, “how do we know that the new copper conductors that were designed and manufactured on-site can withstand the forces of potential fault currents, should the switchboard be subject to a short circuit?” Well, we don’t know.

Air circuit breakers can be designed and modified to fit into the existing switchgear of a switchboard, by a cradle replacement fit, or a hard-bus retrofill design. A cradle fit is simply a roll in replacement, that fits exactly where the old one was removed from, using the same components to operate. Retrofill is a modernisation process replacing the circuit breaker and main functional components of the original switchgear, embedding an integrally safe plug-in technology to connect the new circuit breaker to an existing panel. Air circuit breakers have been designed according to Australian Standards and upgrade options are available for most brands and models.

How much does it cost to install Air Circuit Breakers?

Scenario A: Installation of a Retrofit Air Circuit Breaker

During a buildings routine electrical maintenance shut-down, a retrofit air circuit breaker can be easily measured up for as little as $500 and no interference to the main switchboard’s structure is required. Therefore, no extra downtime is added to the installation of a replacement air circuit breaker when the existing one fails beyond repair. A retrofit air circuit breaker for a low voltage switchboard would take approximately 8-10 hours to install, costing around $20,000-$25,000.

Scenario B: Installation of an Air Circuit Breaker

If a fault was to suddenly arise, the power to the building would be compromised and a shut-down to the entire switchboard would result, for a lengthy period. Installation of a new air circuit breaker would take approximately 2-3 days, equating to around 40 hours of labour and cost between $35,000-$40,000. If a replacement of the entire switchboard was required, this would prove very costly and more importantly could render the building or process in-operative for several weeks.

What are the benefits for Retrofit Air Circuit Breaker installation?

Systems change, loads can increase and environments evolve over time, deteriorating vital electrical equipment. Installing a new low voltage retrofit air circuit breaker offers many advantages over their older counterparts. Key benefits include:

  • no structural changes
  • much smaller than older models
  • increased life cycle of switchgear
  • improved reliability and safety
  • maintaining original configuration of switchgear equipment
  • ease of facility maintenance and functionality of the system
  • low investment costs (compared to those required for the installation of new switchgear or switchboard)
  • planned scheduling and implementation with minimal downtime (cost reduction of maintenance and repairs)
  • service continuity guaranteed with protection of investments
  • provide additional protection and monitoring benefits (adding substantial value to the integrity of the low voltage switchboard)
  • full interconnectivity with existing distribution systems
  • adaptations to auxiliary circuits
  • greater control with new electronic protections
  • upgrading of the switchboard with new technology (as power management and energy saving)
  • customised solutions based on specific client needs.

One of the best solutions is to have a retrofit air circuit breaker designed and installed by an electrical engineer, using Computer Aided Design (CAD). The new, interconnecting coppers can then be tested ensuring they withstand short circuit stresses (set by the computer program). If planned and carried out as a design exercise, the retrofitting of circuit breakers can prove to be a cost effective solution for facility managers, especially on buildings where downtime has to be kept to an absolute minimum. When there is a fault, the new air circuit breaker can be installed in a very short time frame.

 

Prolux Electrical Contractors offer retrofit air circuit breaker installation and programed electrical maintenance for all types of commercial and industrial switchboards. Call us today on 1800 800 880 for a no obligation discussion on how we can improve the efficiency of the buildings you manage.

Commercial Switchboard Maintenance – Goldman Sachs

Prolux Electrical Contractors carried out the annual Power-Down and Power-Up Maintenance on all electrical systems at Golden Sachs, 101 Collins St, Melbourne: Saturday 18th & Sunday 19th April 2015.

Works comprised of full electrical maintenance on 37 Main Switchboards / Distribution Switchboards, including:

  • 287 (Residual Current Device) RCD’s tested and replaced / repaired where required
  • Air Circuit Breaker (ACB) testing
  • Circuit schedules verified and updated
  • UPS input and outputs tested
  • Thermal imaging; including remedial works on 52 electrical items
  • All electrical componentry cleaned
  • Hinges, seals, screws replaced/repaired where required

All works were successfully completed by four teams of Prolux electricians in less than two days, with minimal disruption to the building’s tenants.

 

Call Prolux Electrical Contractors today on 1800 800 880.
Commercial & industrial electrical maintenance, switchboard repairs and thermal imaging.