Schneider NSX Breakers NZ | ComPacT NSX MicroLogic MasterPacT

Schneider ComPacT NSX and MasterPacT Breakers

Schneider / ComPacT NSX and MasterPacT breakers

The trip unit has its own current rating, separate from the breaker frame. An NSX250 fitted with a 100 A trip unit is a 100 A breaker.

ComPacT NSX is the Schneider moulded case range and MasterPacT the air circuit breaker range, both under the Pact Series name. In switchboards across New Zealand.

The frame and the trip unit are rated separately

Start here, because it changes what you order.

A trip unit such as the MicroLogic 2.2 is sold with its own rating and fits several frame sizes. Schneider lists one part as a MicroLogic 2.2 for Compact NSX 100, 160 and 250, rated 100 A, 3 pole.

Component	What it sets
Frame	Maximum capability and physical size. NSX100, 160, 250, 400, 630
Trip unit	The actual protection rating and settings

So reading the frame off the front does not tell you the breaker's rating. You need the trip unit too.

It also means a trip unit failure does not need a new breaker, and that is a substantial saving. Tell us whether you need the breaker, the trip unit, or both.

Trip units need snap-off screws, and they are single use

A small part that stops a job, and Schneider is emphatic about it.

It is mandatory to use snap-off screws LV429513 to install a MicroLogic trip unit, and when installing you must check that the snap-off screws break when tightened.

They break by design, which means they cannot be reused. Every trip unit fit needs a new set.

So if you are ordering a trip unit, order the screws with it. Without them the job stops, and an ordinary screw is not a substitute.

Schneider also notes that MicroLogic 5 and 6 trip units must be installed with the internal rubber insulation screen in the right position.

Changing to a different rating

If a replacement trip unit has a different rating from the one removed, Schneider requires that you adapt the connection characteristics.

So a rating change is not just a swap. Tell us if you are changing rating rather than replacing like for like.

The MicroLogic digit is the protection set

MicroLogic	Protection
2	Long time, short time, and fixed instantaneous
5	Long time, short time, instantaneous, all adjustable
6	As 5 plus earth fault
7	As 5 plus earth leakage

The step from 5 to 6 adds earth fault protection. If the installation relies on it, a MicroLogic 5 is not a substitute for a 6, and nothing about the breaker will tell you it is missing.

Same principle as the G in Ekip LSIG on our ABB Tmax page.

What a MicroLogic 2 actually adjusts

Worth knowing, because the answer is less than people assume.

Setting	Adjustable?
Long time pickup, Ir	Yes. Two dials
Long time delay, tr	No. Fixed
Short time pickup, Isd	Yes. In multiples of Ir, precision plus or minus 15 percent
Short time delay	No. Fixed
Instantaneous	Fixed

Neither time delay is adjustable on a MicroLogic 2. If a discrimination study calls for a specific time delay, that needs a MicroLogic 5 or above.

The two-dial long time setting

The long time pickup Ir uses two dials working together:

Dial	Function
Preset dial	Sets Io, displayed in amperes. The maximum preset equals the trip unit rating In
Adjustment dial	Fine tunes Ir, displayed in multiples of Io

Both dials matter and both need recording before a trip unit is removed. A replacement arrives at default, and reading only one dial gives you the wrong setting.

Photograph the front. That is the whole answer.

Neutral protection on four pole breakers

On a four pole breaker, neutral protection is set on the trip unit using a three-position dial.

Another setting that arrives at default on a replacement, and one that is easy to overlook because it is not about the phases.

The NSX400K exception

Worth flagging because it breaks the pattern.

The ComPacT NSX400K is equipped with a non-interchangeable MicroLogic 2.3 trip unit with no test port.

So on that specific breaker the trip unit is not a separate orderable part, and there is no test port for a secondary injection test.

If your breaker is an NSX400K, the trip unit and the breaker are one item.

NS and NSX accessories are compatible one way only

An excellent piece of information from Schneider's own substitution guide, and it decides whether an upgrade is straightforward.

Accessory	On a Compact NS	On a Compact NSX
NSX rotary handle	Yes	Yes
NS rotary handle	Yes	No
NSX motor mechanism	Yes	Yes
NS motor mechanism	Yes	No

The newer accessory works on both. The older one does not.

So when replacing a Compact NS with an NSX, the handle and motor mechanism have to come from the NSX range. And if you are buying an NSX accessory, it will also serve an older NS breaker elsewhere on site.

That makes NSX accessories the sensible thing to stock on a mixed board.

The cutouts are the same

Good news for a substitution. For Compact NSX there is only one cutout for all control types, and it is identical in size to the large cutout for Compact NS.

So the door does not change.

There is also a larger cutout option that provides access to the trip unit. With the standard cutout, access to the trip unit is not possible without opening the door.

Worth deciding at design stage. If the settings need checking regularly, the larger cutout saves opening a live board.

Reading an NSX designation

Take NSX250H.

Part	Meaning
NSX	Range
250	Frame size in amps
H	Breaking capacity class

Breaking capacity classes run F, N, H, S and L, with K on certain frames. The letter is the fault performance, not a model variant.

An NSX250F and an NSX250H are the same frame with different breaking capacity. Substituting down is a protection decision that depends on the prospective fault current at that point, and it belongs with whoever did the fault level study.

Same convention as ABB Tmax XT and Emax.

Physical details

Item	Value
Pitch, NSX400 and NSX630	45 mm across F, N, H, S and L
Pitch with spreaders	52.5 mm, fixed front or withdrawable

Spreaders are a separate set, and they change the connection pitch. If your busbar is on 52.5 mm centres, that is why.

Plug-in and withdrawable need auxiliary connectors

A separate order line that gets forgotten.

Schneider notes that if any internal accessories are required for plug-in and withdrawable devices, add the necessary auxiliary connectors, giving LV429273 and LV432523 as examples.

So a withdrawable breaker with auxiliary contacts needs the connectors that carry those signals through the cradle. The breaker and the auxiliaries alone are not enough.

Also note the safety trip interlock LV432520 for NSX400 and NSX630.

The ranges

Range	Type	Status
ComPacT NSX	Moulded case, 100 to 630 A	Current
ComPacT NSXm	Smaller moulded case	Current
Compact NSX	Previous name for the same range	Renamed
Compact NS	Earlier moulded case range	Superseded
Vigicompact	NSX with integral earth leakage	Current
MasterPacT MTZ	Air circuit breaker	Current
MasterPacT NW, NT	Air circuit breaker	Superseded by MTZ
PowerPacT	North American moulded case	Current

Pact Series is the umbrella name covering ComPacT, PowerPacT and MasterPacT.

Vigi is the earth leakage function. A Vigicompact is an NSX with earth leakage protection built in, and it is a different part from a plain NSX.

MicroLogic spans the ranges

Schneider notes that MicroLogic electronic trip units are designed for use in both PowerPacT and MasterPacT circuit breakers.

The more advanced units add energy and power quality metering.

So a MicroLogic is not automatically interchangeable across ranges, but the family spans them. Send the full trip unit reference along with the breaker.

The Ready LED

A useful diagnostic. On the MicroLogic 2.2, the green Ready LED flashes if the circuit breaker is ready to trip, and alarm LEDs indicate overloads.

A trip unit with no flashing Ready LED is not ready, and that is worth checking before assuming the breaker is fine.

What to send us

The frame and breaking capacity letter. NSX250H and so on.

The trip unit type and its rating. These are separate.

The dial settings, photographed. Both long time dials, the short time dial, and the neutral dial on a four pole.

Pole count.

Fixed, plug-in or withdrawable, and whether you need auxiliary connectors.

Whether you need the snap-off screws. You almost certainly do.

Whether it is a Vigi version.

What we can supply

Current production. ComPacT NSX and NSXm, Vigicompact, MasterPacT MTZ, MicroLogic trip units, rotary handles, motor mechanisms, auxiliary contacts, connectors, spreaders and snap-off screws. Quoted with a delivered lead time.

Trip units separately. Often the cheaper repair.

Superseded. Compact NS, MasterPacT NW and NT, and earlier trip units. Surplus and tested used, which keeps an existing board as it is.

We buy Schneider breakers

Moulded case and air circuit breakers hold significant value, and so do MicroLogic trip units. If a switchboard is being replaced, do not scrap the breakers or the trip units. See Sell To Us.

Send us your references

Send the breaker and the trip unit separately, because they are separate parts with separate ratings. And order the snap-off screws with any trip unit. Quotes in NZD including GST.

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Industech is an independent supplier of new, surplus and used industrial automation equipment. We are not an authorised distributor of, approved by, sanctioned by, or affiliated with Schneider Electric. Schneider Electric, ComPacT, MasterPacT, PowerPacT, MicroLogic, Vigicompact and Pact Series are trademarks of Schneider Electric. All trademarks, brand names and references are the property of their respective owners and are used here for identification purposes only. Information on this page is for identification and does not constitute electrical design advice. Breaking capacity and protection settings depend on the installation and belong with whoever is responsible for its protection design.