NLS | 3P+N RCBO 32A 6kA C Curve | 30mA Type A with Neutral Lead
The NLS 30937 is a three-module RCBO rated 32A, combining overload, short circuit, and 30mA earth leakage protection in one 3P+N device. The 30937 switches three active poles and carries a solid neutral fed by a 900mm lead. It has a 6kA breaking capacity, a C curve tripping characteristic, and Type A residual current sensing rated 400/415VAC.
Prospective fault current rises as a circuit sits closer to the supply, and a 32A three-phase circuit frequently sits close. A protective device must interrupt the fault current available at its terminals, not merely the load it carries in service. The 30937 provides a 6kA breaking capacity, so the prospective fault current at the point of installation requires checking against that figure before the device is specified.
A shared RCD protecting several three-phase circuits drops the entire group on a single earth fault, and the callout then begins with splitting the group to locate it. The 30937 places overload, short circuit, and earth leakage protection on one circuit, so a fault isolates that circuit alone. It mounts on standard 35mm DIN rail and accepts line conductors to 35mm², with a 900mm neutral lead reaching the bar.
Features
- 32A rated current — sized for three-phase circuits drawing up to 32A per phase.
- 6kA breaking capacity — interrupts prospective fault currents up to 6000A; verify the fault level at the point of installation does not exceed this figure.
- Per-circuit protection — the 30937 combines overload, short circuit, and earth leakage protection on a single circuit rather than across a shared RCD group.
- 3P+N in three modules — the 30937 switches three active poles and carries a solid neutral, inside the 54mm width of a standard 3 pole MCB.
- Solid neutral on a 900mm lead — the neutral is not switched; it lands at the bar through a 900mm flying lead, with a spare crimp ferrule supplied.
- Type A earth leakage sensing — detects sinusoidal AC and pulsating DC residual current, rated at 30mA.
- C curve tripping — magnetic trip at 5 to 10 times rated current, which allows normal inrush on motor and mixed load circuits.
- Line terminals to 35mm² — the 30937 accepts line conductors up to 35mm² and load conductors up to 25mm², torqued to 2.5Nm.
- 400/415VAC rated — operates at 50/60Hz on standard Australian three-phase supply.
- 35mm DIN rail mounting — clips to standard rail without adaptors or backing plates.
- Tested endurance — rated beyond 6000 electrical operations and 10,000 mechanical operations.
- IP20 rated — the 30937 is finger-safe at the terminals only, which suits mounting inside a switchboard rather than exposed or damp locations.
Where to use
- Larger three-phase circuits — the 30937 covers loads drawing up to 32A per phase on a single protective device.
- Circuits needing individual isolation — suits installations where an earth fault should drop one circuit rather than a shared RCD group.
- Boards with verified fault levels — appropriate where the prospective fault current at the device is confirmed at or below 6kA.
- Three-phase motor circuits — the C curve absorbs start-up inrush at 5 to 10 times rated current without tripping.
- Three-phase-three-wire circuits — the manufacturer lists motor circuits running without a neutral among the intended applications for this device.
- Dual-phase appliances — listed by the manufacturer as an intended application, covering appliances that draw across two phases.
- Switchboard upgrades — the 30937 replaces an existing 32A 3 pole MCB in the same 54mm width, adding earth leakage protection without widening the board.
The 30937 is not suitable for 480V single phase SWER supply, and is not rated for installations where prospective fault current exceeds 6kA. It is rated IP20, which suits mounting inside a switchboard enclosure rather than exposed or damp locations. On circuits carrying EMC filtering, such as inverter drives, the filtering can cause unwanted tripping, so confirm the recommended residual current device type with the equipment manufacturer.
