MoellerNZM6-1603-Pole 160 A Frame Molded Case Circuit Breaker, Adjustable Thermal and Magnetic Trip, 690 V AC IEC / 600 V AC UL

Product Description

What this part is

A Klöckner Moeller NZM6 molded case circuit breaker in the 160 A frame, three-pole. The NZM6 breaker is a two-part product by design: NZM6-160 is the frame, and the trip unit that plugs into it carries its own ZM6 number that sets the actual thermal and magnetic ranges. Under IEC/EN 60947-2 it works as an inverse-time molded case circuit breaker with adjustable thermal and magnetic trips; under UL 508 and CSA 22.2 No. 14 the same device is listed as an HP-rated three-pole manual motor disconnect with built-in thermal overload trips.

Decoding the designation

NZM – Moeller molded case circuit breaker / motor disconnect switch family6 – frame series 6, covering 63 A, 100 A and 160 A frames160 – frame rating in ampsA ZM6-… suffix, where present, is the interchangeable trip module: ZM6-125 or ZM6-160 in this frame, with the trailing number in codes such as ZM6-125-2000 giving the top of the adjustable magnetic trip rangeNZMH6 rather than NZM6 marks the current-limiting high-fault version; -CNA and -NA suffixes mark the North American listing variants

What these specs mean in practice

Two adjustments matter on this breaker and they do different jobs. The front thermal dial is set to motor full-load current and gives overload protection; the magnetic trip sets the instantaneous pickup for short circuits, typically 1000 to 2000 A on a 125/160 A trip module. Per NEC, on a motor circuit the branch-circuit overcurrent protection still has to be provided separately — the NZM6 as a listed motor disconnect is not itself the branch-circuit device. For direct-on-line motor switching it is used with a listed magnetic contactor rather than as the switching element. Note that the 690 V figure is the IEC rated operational voltage; UL and CSA ratings for the family are stated at 600 V AC.

Published ratings and mounting data

Frame rating: 160 A, three-poleRated operational voltage: 690 V AC per IEC/EN 60947-2; 600 V AC under UL/CSATypical trip module ranges in this frame: thermal 100 to 160 A adjustable, magnetic 1000 to 2000 A adjustable (ZM6-160 class module)UL/CSA short-circuit current rating, standard NZM6B with ZM6 trip: 25 kA at 240 V AC, 25 kA at 480 V AC, 14 kA at 600 V AC (RMS symmetrical)UL/CSA short-circuit current rating, high-fault NZMH6: 100 kA at 240 V AC, 65 kA at 480 V AC, 25 kA at 600 V ACStandards: IEC/EN 60947-2, UL 508, CSA 22.2 No. 14; CE markedLine and load field-wiring terminals for cable connection are standard on this series

Quantity and configuration

Sold as 1 piece. In the NZM6 series the operating handle is supplied separately as a catalogue accessory, and so are rotary handle extensions, shunt and undervoltage trips, auxiliary and alarm switches and terminal shrouds — none of those are included here. If the breaker is going into an existing enclosure, the handle and shaft you already have will usually carry over.

Fitting notes

Set the thermal dial to the motor full-load current, then set the magnetic trip high enough to ride through motor inrush but low enough to be selective with what is upstream. Where the assembly needs a declared short-circuit rating as a combination motor controller, that rating is established only for the specific listed combination and enclosure — the breaker’s own interrupting rating is not automatically the assembly’s. Confirm which ZM6 trip module is fitted before commissioning, because it, not the frame number, determines the current ranges you can actually dial in.

Interchange guidance

NZM6-160 and NZM9-250 are different frames with different footprints, terminal spacings and interrupting ratings — not substitutes for each other. NZMH6-160 is the high-fault current-limiting version and is an upgrade in interrupting capacity, not a like-for-like part. N6-160-CNA looks similar but is a non-automatic disconnect switch with no overload or short-circuit trip at all, rated only 10 kA at 600 V AC. Within the NZM6-160 frame, swapping to a different ZM6 trip module changes the thermal and magnetic ranges, which is normally the point — but it also changes the catalogue number, so quote the full frame-plus-module string when ordering. The NZM6 generation is legacy Moeller, superseded by Eaton’s NZM1 to NZM4 range, which is not mechanically interchangeable.