Ampcontrol has developed a unique arc fault vent design and testing regime which set benchmarks in performance and type testing.
A demonstration conducted at Ampcontrol Mackay showcased an enclosure subjected to simulated 22kA and 30kA arc faults. The enclosure was fitted with Ampcontrol’s unique arc vent design which ensures fast reliable venting; maximising personnel safety and protecting equipment.
The demonstration used specialised pyrotechnic materials that emulate the effect of arc faults in electrical enclosures. The controlled explosions generate pressure and time characteristics that are typical in arcing faults. These explosives triggered inside enclosures enable us to evaluate venting arrangements.
This testing method avoids the need to send equipment to specialist test facilities. It is also portable and can be taken to site if required and many tests can be completed in a single day.
This testing approach supports compliance testing for large enclosures that can’t be accommodated in existing test facilities and provides a convenient solution for type testing large equipment enclosures.
The test data can be used to determine safety margins on given designs and produce venting solutions for all sizes of enclosures, eliminating the need to conduct additional testing when retrofitting equipment, reducing turnaround times.
More about Arc Fault Management
Management of arc faults in electrical enclosures is needed to protect personnel and plant from the rapid pressurisation of electrical enclosures to avoid catastrophic mechanical failure of the cubicle.
Arc fault management generally utilises one of three strategies:
- Prevention – in which the design, layout and materials in the enclosure reduce the likelihood of an internal arc fault occurring
- Mitigation – in which the duration and energy of any occurring arcs is limited by protection regimes that reduce the fault energy to moderate levels
- Venting – in which steps are taken to manage the products of an arc fault until upstream protection clears the fault
The ideal situation is prevention, though in practice this approach is not sufficiently practical to remove the need for additional strategies.
Mitigation strategies include active devices such as optically triggered shorting switches and passive approaches such as line side fuses. The active approaches require high and proven integrity levels to meet required safety objectives. Passive approaches need careful design to match load transients and source impedances, both of which can vary during typical operations. In general, this approach can only be taken for new equipment and is not easily retro-fitted to existing installations.
Arc venting seeks to protect the mechanical integrity of the electrical enclosure by ensuring dedicated sacrificial panels open to the atmosphere to prevent enclosure pressurisation and subsequent failure. While simple in principle, testing has demonstrated that rapid deployment of the vent panels is critical to function.
Ampcontrol has developed a vent design that exploits the dissimilar properties of key materials in a true composite structure to ensure fast reliable venting. When matched to a given enclosure’s mechanical strength and the nominated fault current levels, Ampcontrol’s new vent covers offer a significant advancement in proven venting technology.