According to the Australian Institute of Health & Safety, there are between six and eleven incidents involving arc faults each year in Australia that result in serious burns or death. Implementing these seven safety measures can reduce the risk of dangerous arc fault events and ultimately save lives.
NHP Channel Manager – Regulatory & Standardisation, Jeff Davis – who has been on committees to design electrical standards including EL-06-08 Switchboards, EL-001 3000 Wiring Rules, EL-001-17-01 Construction and Demolition and EL-007 High Voltage Switchgear – explained how disaster could be avoided by following seven simple steps.
NHP’s CUBIC Modular system can protect personnel from dangerous arc fault events if all the doors and covers are in place on the switchboard.
2.Incorporate polycarbonate covers
By adding polycarbonate covers to busbars and all connection joints you can come close to eliminating the risk of an arc flash.
3.Opt for a fast-acting circuit breaker
A fast-acting air circuit breaker (ACB) is a must have. NHP’s Terasaki TemPower 2 is the fastest acting ACB on the market. A single millisecond is a lifetime where high-incident energy exists, so an ACB that opens and clears the fault as quickly as possible is essential. The TemPower 2 does it comfortably within 30 milliseconds. One of the highest risk operations with any switchboard is switching the main ACB on or off, because at that point you’re connected directly to the transformer. NHP’s Terasaki ACBs and TemBreak Pro moulded case circuit breakers can be operated remotely, so personnel don’t have to enter the switchroom to perform this procedure.
4.Install a photo-optic sensor
Photo-optic sensors like Rockwell Automation’s ArcLogix use fibreoptic tubes – or point sensors – laid throughout the switchboard. If an arc flash occurs, extremely bright energy of approximately 10,000 lux is released and detected super quickly. It signals to the ACB to open and remove the supply to the switchboard, ultimately reducing the level of damage.
5.Install moulded case circuit breakers
This allows you to reduce the risk of arc faults even further, by segmenting the reticulation system into smaller groups, which are controlled by fast operating, current limiting moulded case circuit breakers.
6.Eliminate human exposure
The other high-risk operation is to rack the main ACB in or out. NHP’s TemRack iR is an automated ACB racking device, which is installed within the body of the ACB and allows for the remote racking of the ACB, thus eliminating the need for humans to enter a live switchroom and be exposed to dangerous arc fault events.
7.Install live line indicators
REMLIVE live line indicators can be installed in the CUBIC switchboard, providing a visual reminder that a circuit is live, which reduces the risk of accidents, speeds up the fault-finding process and ultimately saves lives.
PPE is the least effective method of protection and reliability in the “hierarchy of control”, while “elimination”– which the above steps achieve – is the most effective means of protecting personnel. Given personnel don’t have to enter the switchroom, they are also not required to wear heavily insulated PPE, which has been the cause of recent incidents of heat fatigue.
The unique Arc-Killer for medium voltage safety
NHP’s Arc-Killer is a unique worldwide patented, fast-acting earthing switch system that diverts a high energy arcing fault into the low energy short circuit, which is finally cleared by an upstream circuit breaker. Arc quenching is achieved within 48 milliseconds for the DF-2+ switchgear and 25 milliseconds for the DR-6+ RMU, protecting people from significant injury.
NHP’s Services and Solutions Team is available to visit your site to assist you with implementing these measures into your switchboards, including ACB retrofits and connecting TemRack iR into your existing TemPower 2 ACB.
