The special requirements of air-con circuit protection

ABB Australia Pty Ltd

Monday, 21 June, 2021

The special requirements of air-con circuit protection

To satisfy the safety requirements of more stringent Australian wiring standards, ABB has introduced new residual current protection technology.

Australian Wiring Standards have been reviewed to acknowledge the increased use of electronics, as well as renewable and emerging technologies, where there is a greater impact from high frequency and DC waveforms on the AC supply.

The latest legislation, AS/NZS 3000:2018 Electrical Installations “Wiring Rules” clause, now requires all final sub-circuits in domestic and residential electrical installations to be protected by 30 mA RCDs. As a result, many air-conditioning manufacturers with inverter drives are recommending the use of Type F RCDs (residual current device) for the upstream protection of this equipment.

To meet these new standards, ABB’s residual current protection range now includes Type AC for basic linear loads with alternating current earth faults. The offer includes type A for loads with electronic rectifiers or phase control generating alternating current and pulsating DC earth faults, Type F for single phase frequency inverters generating multi-frequency currents and Type B for three-phase inverters generating multifrequency and smooth DC earth faults.

A single-phase air-conditioner frequency converter, commonly referred to as an inverter, is an often-used electronic drive which regulates the speed of an electric motor, operating on supply voltage and frequency. An incorrectly selected RCD can lead to nuisance tripping, poor performance and poor protection.

With the introduction of Type F to the ABB RCD range, ABB can now offer the ultimate in reliability, safety and performance for the demanding load of frequency converters.

Type F RCDs have been specifically designed for single-phase inverter applications to ensure superior protection in case of an earth with increased resistance to nuisance tripping including the ABB DS201 Type F RCBO (MCB+RCD).

“ABB’s new Type F RCDs clearly respond now to changing legislation and customer needs for reliable and accurate protection of circuits supplying single-phase inverters with a proven solution,” said Ian Richardson, Market Development Manager, Energy Distribution, Electrification business, ABB Australia.

“The DS201 Type F RCBO provides an ideal solution for sub-circuit protection of air conditioners in domestic and residential applications. The DS201 Type F is economic in both cost and space to provide the compliance required for AS/NZS 3000:2018.”

For severe loads, the ABB Type B RCD provides protection with increased frequency range and the capability to detect smooth DC earth faults.

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