Arc faults are a serious event where a large amount of electrical energy is explosively released causing serious burns and death of operators in the area. Additionally, they can result in significant damage to switchgear, conductors, switchboards and installations. Here we look at how new electrical safety technology can prevent disaster and protect personnel from hazardous consequences.
The most likely time for an arc fault to occur in a switchroom is during electrical and mechanical operations, such as switching, isolation and racking of circuit breakers. It is common practice in the industry to use arc flash personal protective equipment (PPE) for operator protection during these operations, however it is ideal to isolate the operator entirely from the arc fault hazard.
Controlling the risk
To control any risk in the workplace, the hierarchy of controls is used to determine what action will best reduce or remove the hazard at hand. In order of most to least effective, the hierarchy includes elimination, substitution, isolation, engineering controls, administrative controls and PPE.
In the case of arc faults, elimination and substitution are not possible, so instead we should take steps to reduce the overall risk through isolation, which involves personnel being separated from the energised electrical equipment and conductors. Ideally, personnel would not have to operate or perform work on the electrical equipment.
Racking air circuit breakers remotely
The time spent in a potentially dangerous area can be minimised by utilising common accessories for switchgear, which facilitate remote operation, such as motor operators and open/close coils. There are also methods available to complete the racking of circuit breakers remotely. These allow the operator to be away from the switchroom when switching and racking operations are occurring.
NHP’s TemRack iR is a fully integrated automated racking device, which enables remote racking of the Terasaki TemPower 2 AR Air Circuit Breaker (ACB) body in and out of its associated carriage. The automated racking function permits safe isolation of the ACB with zero physical interaction between personnel and the ACB, thereby reducing the risk of exposure to explosive arc fault events and high incident energy.
TemRack iR’s mechanical interlocks and safety functions integrate seamlessly with the ACB and the ACB’s functionality remains unaffected. Similarly, onsite electrical protection methodology/systems also remain unaffected. It features integrated digital I/O for control and feedback, allowing the operator to remotely rack the ACBs in or out from outside the switchroom.
Remote control can be performed via a local control station or other remote methods utilising the integrated I/O on your automation system. Where ACBs are fitted with open/closed coils, the remote operation of the ACB can also be performed as a further risk mitigation strategy.
NHP’s TemRack iR can be fitted as part of a new ACB build or retrofitted to an existing Terasaki AR ACB by NHP’s Service and Solutions Team. Minimise your risks and maximise your safety on site with NHP’s TemRack iR.
For further information, please call 1300 NHP NHP or email [email protected]
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