ABB Emax 2 vs Schneider MasterPact MTZ: Air Circuit Breaker Comparison

What is an air circuit breaker comparison between ABB Emax 2 and Schneider MasterPact MTZ? An ABB Emax 2 vs Schneider MasterPact MTZ comparison evaluates two low-voltage ACBs rated up to 6300 A under IEC 60947-2, each offering ultimate breaking capacities (Icu) reaching 150 kA at 415 V with fully electronic trip units and native digital communication. Selecting the wrong platform — mismatched Icu/Ics ratings, incompatible SCADA protocols, or underestimated mechanical endurance requirements — risks protection failures, forced downtime, and non-compliance with arc-flash coordination studies. This guide covers breaking capacity and short-circuit performance, Ekip versus MicroLogic X trip unit intelligence, mechanical and electrical endurance ratings, communication architecture and digitalization, and a practical sizing calculator.

Published: 2026-04-27 | Last updated: 2026-04-27 | By Stoklink Engineering Team

The decision matters because an ACB at the incomer of a 2 MVA transformer is not a commodity. A wrong choice cascades into ten years of spare-parts headaches, retrofit pain when the protection coordination study gets revised, and — worst of all — nuisance trips at 3 a.m. when the on-call engineer has no idea why the LSIG curve was shaped the way it was. So we will be specific. Concrete values, real catalogue references, named clauses.

What exactly are we comparing: Emax 2 and MasterPact MTZ at a glance

Both the ABB Emax 2 and MasterPact MTZ ranges target the same application space: low-voltage incomers, bus-tie breakers, and large outgoing feeders in industrial and commercial switchgear. They are not interchangeable, but the design intent is similar enough that procurement teams often request quotations from both vendors for the same single-line diagram.

The Emax 2 family

ABB's Emax 2 splits into four frame sizes: E1.2 (up to 1600 A), E2.2 (up to 2500 A), E4.2 (up to 4000 A), and E6.2 (up to 6300 A). Breaking capacity (Icu) ranges from 42 kA on the E1.2B up to 200 kA on the E6.2X at 440 V. The flagship feature is the Ekip trip unit, which goes from a basic Ekip Dip up to the Ekip Hi-Touch with full IEC 61850 GOOSE messaging and embedded power-quality analytics.

Typical references we ship from stock include the ABB 1SDA070701R1 E1.2B 630 A 42 kA Ekip Dip LI for small generator outputs, the ABB 1SDA070821R1 E1.2B 1250 A for mid-size MDBs, and the ABB 1SDA070981R1 E2.2B 1600 A as a step-up frame when future expansion is on the table. For a deeper view of the range, see what is the ABB SACE Emax 2.

The MasterPact MTZ family

Schneider's MasterPact MTZ also splits into three main frames: MTZ1 (630–1600 A), MTZ2 (800–4000 A), and MTZ3 (4000–6300 A). Breaking capacity tops out at 150 kA at 440 V on the MTZ3 H3. The trip unit is the MicroLogic X, which Schneider markets heavily for its smartphone Bluetooth connection and embedded "digital modules" — software features sold as licensed add-ons.

For complete technical specifications and ordering data of the ABB Emax 2 range, refer to the ABB SACE Emax 2 product portfolio, which documents frame ratings, Ekip trip unit variants, and compliance with IEC 60947-2.

Breaking capacity and short-circuit performance

Breaking capacity is where most ABB Emax 2 and MTZ specifications start, and rightly so. The breaker has to clear the maximum prospective short-circuit current at the installation point without welding, fragmenting, or causing collateral damage to adjacent gear.

For a 2000 kVA transformer at 400 V with uk = 6%, that gives roughly 48 kA. So an E1.2B at 42 kA is already marginal, and you would step up to the E2.2N at 66 kA — or on the Schneider side, the MTZ2 N1 at 65 kA. In practice, both manufacturers offer comparable Icu values in the relevant ranges, though there are pockets where one is meaningfully better.

Where Emax 2 has the edge

At 690 V — common in marine, oil & gas, and large pump installations — the Emax 2 E2.2 retains 66 kA Icu in the N performance class, whereas the MTZ2 drops to 50 kA at the same voltage. For petrochemical clients running 690 V motor switchboards, this is not a minor detail. We have seen at least two retrofit projects where the original MTZ frame had to be upsized because the short-circuit study was revised after a transformer upgrade, and the Emax 2 in the same physical footprint would have absorbed the change.

Where MasterPact MTZ has the edge

At the very top end — 6300 A frames at 440 V — Schneider's MTZ3 H3 publishes 150 kA Icu, which matches the Emax 2 E6.2X. They are functionally equivalent. Below 4000 A there is no real differentiator in pure breaking capacity for most projects.

Trip unit intelligence: Ekip vs MicroLogic X

This is where the ABB Emax 2 vs MTZ comparison gets interesting, and where engineers often overlook the long-term implications. The trip unit determines not just protection coordination but how the breaker integrates into a building or plant management system over its 25-year service life.

Ekip platform philosophy

ABB sells Ekip as a hardware-tiered platform: Dip, Touch, Hi-Touch, G Hi-Touch. You choose the hardware tier at order time and it ships with the protection functions baked in. LSI, LSIG, neutral protection, earth-fault, directional protection — all selected by part number. The ABB 1SDA070782R1 E1.2B 1000 A Ekip Dip LSI, for example, ships with full LSIG-capable hardware but the G (ground) function is software-enabled via Ekip Connect.

What we typically see in the field: the Ekip Touch interface is more intuitive for switchboard technicians who do not want to pair a phone every time they need to read a setting. The dot-matrix display shows real-time currents, last trip cause, and waveform capture without any external device. For routine maintenance walks, this saves time.

MicroLogic X philosophy

Schneider takes the opposite approach. The MicroLogic X hardware is the same across the range; differentiation happens through software "digital modules" you license from the EcoStruxure Power app. Power metering Class 1, waveform capture, predictive maintenance — all add-on purchases. Some engineers argue this is more flexible because you can unlock features later. In my experience, it more often becomes a budget surprise three years post-commissioning when the facility manager discovers that the metering accuracy they assumed they were paying for is actually a $1200 license per breaker.

The Bluetooth/smartphone connection is genuinely useful for spot diagnostics, but it requires the local engineer to install the app, get cybersecurity clearance on a corporate phone, and maintain the pairing. Not always a smooth path on a regulated industrial site.

Mechanical and electrical endurance

Endurance numbers tell you how often the ABB Emax 2 — or any comparable ACB — can be operated before it needs major service. For a tie-breaker in an automatic transfer scheme that switches twice a week for 20 years, this matters.

For a more detailed Siemens comparison, see ABB Emax 2 vs Siemens 3WL.

The "feels overbuilt" factor

Numbers on a datasheet are one thing. Picking up the breaker in a workshop is another. The Emax 2 cradle feels noticeably more rigid than the MTZ cradle in the same current rating — heavier brass shutters, sturdier rails. Whether that matters depends on your service environment. In a clean data center, no. In a cement plant where the panel gets vibration from a nearby raw mill, yes.

Communication architecture and digitalization

Modern switchgear, including the ABB Emax 2 and its competitors, is judged as much on its data interfaces as on its protection performance. Both manufacturers support the major industrial protocols, but the integration patterns differ.

ABB approach

ABB sells dedicated Ekip Com modules: Modbus RTU, Modbus TCP, Profibus DP, Profinet, EtherNet/IP, IEC 61850, and DeviceNet. Each is a snap-on module to the trip unit. Importantly, IEC 61850 with GOOSE messaging is supported natively on the Ekip G Hi-Touch — meaning the breaker can publish a "trip armed" signal to a peer breaker in under 4 ms without going through a separate gateway. For zone-selective interlocking (ZSI) across multiple boards, this is the cleanest topology we have deployed.

Schneider approach

MicroLogic X integrates through the IFE or EIFE Ethernet interface, which acts as a gateway. Modbus TCP is well supported. IEC 61850 is available, but the architecture typically routes through the gateway rather than embedding directly in the trip unit. This adds one network hop. For most building-management applications it makes no practical difference. For high-speed protection schemes, the ABB native approach is cleaner.

Sizing and selection: a practical calculator

Frame selection looks easy on paper but trips up junior engineers regularly. The rated current In is not the only number; you have to derate for ambient temperature, switchboard ventilation, and harmonic content. For a structured walkthrough, see how to size ABB Emax 2: step-by-step calculator.

Working through an example: a continuous load of 1400 A in a panel running at 50 °C internal temperature gives roughly 1882 A. That pushes you to a 2000 A frame, which on the ABB side would be the ABB 1SDA071021R1 E2.2B 2000 A. On the Schneider side, an MTZ2 20 N1.

Total cost of ownership: beyond the unit price

List prices for comparable ABB Emax 2 and MasterPact MTZ frames are remarkably close — within 5–8% across the two ranges in most regional markets. The real cost differences appear elsewhere.

Spares and lead time

ABB's Emax 2 has been in production since 2014 and the spare-parts ecosystem is mature. Replacement trip units, contacts, and motor operators are typically available within 2–4 weeks globally. The MTZ launched in 2017 and is also well-supported, but in some regions we still see longer lead times for specific MicroLogic X variants — particularly when a digital module license has to be re-issued for a replacement unit.

Software licensing

This is the quiet cost driver. A MasterPact MTZ with all "digital modules" enabled (waveform capture, ION-class metering, predictive maintenance) can add €800–€1500 per breaker over the project life. The equivalent functionality on an Ekip Hi-Touch is included in the hardware tier price.

Retrofit kits

Both manufacturers offer retrofit kits for replacing legacy breakers (Emax 1, MasterPact NW) within existing cubicles. ABB's RetroFITT-able kits are particularly well-engineered for swapping older Emax 1 units; the bus connections and door cutouts often match without panel modification. Schneider's MTZ retrofit on existing MasterPact NW cubicles works similarly. For brownfield projects, this is a meaningful selection criterion.

Application scenarios: where each one fits

Data center main distribution

For Tier III/IV data centers, redundant power feeds with sub-cycle transfer requirements lean toward the ABB Emax 2 because of the native IEC 61850 GOOSE in the trip unit. We covered this in detail in our piece on Emax 2 in data center MDB design.

Marine and offshore (690 V systems)

Emax 2 wins here on Icu performance at 690 V and on type approvals from the major classification societies (DNV, ABS, Lloyd's Register). MTZ also has marine approvals but the breaking-capacity headroom is smaller.

Commercial buildings

Either works. Schneider tends to have stronger pricing on standard 1600–2500 A configurations in some regional markets, particularly in France and the UK where local stock is deep. ABB tends to be stronger in DACH and the Middle East.

Heavy industry with high harmonics

Variable-frequency drives create THD that can falsely trigger thermal overcurrent functions. Both trip units handle harmonics, but the Ekip Touch's true-RMS measurement up to the 51st harmonic is documented; the MicroLogic X claims similar but the published bandwidth is the 31st. For arc furnace or large VFD installations, this matters. We have a separate article on Emax 2 nuisance tripping causes that addresses this directly.

Installation and commissioning notes from the field

A common mistake on both products: torquing the bus connections to the wrong specification. The ABB Emax 2 horizontal rear connections call for 70 Nm on M12 studs (per ABB document 1SDH001000R0002); the MTZ equivalent is 50 Nm on M10. Using the wrong torque value leads to overheating at the joint within months, and the cause is misdiagnosed as "the breaker is faulty" when it is actually a loose primary connection.

Another field pattern: setting the long-time pickup (Ir) too tight on commissioning day. Engineers often size Ir at 1.0× In to "be safe", then get nuisance trips during morning startup when motor inrush adds 20% to the steady-state current for 30 seconds. Both Emax 2 and MTZ allow Ir as low as 0.4× In; in practice, 0.95× In with a generous tlong delay is the right starting point for most distribution applications. For full technical specifications, see ABB Emax 2 full technical specifications.

For specific frame sizes we keep in stock, browse our full air circuit breakers collection, along with complementary protection devices in the miniature circuit breaker, residual current device, and relay ranges.

Cubicle ventilation and ambient temperature

Both manufacturers publish derating curves in their technical catalogues, but the assumptions differ. ABB rates the Emax 2 at 40 °C ambient inside the switchboard with full performance; above 50 °C, derating begins. Schneider's MTZ uses similar reference conditions. The trap: both vendors quote the breaker temperature, not the panel ambient. Engineers often confuse the two.

If the room is at 35 °C and the panel internals run 15 °C above ambient (typical for a moderately loaded switchboard with no forced ventilation), you are already at 50 °C internal — which means the 1600 A rated breaker effectively delivers around 1490 A continuous. For projects in the Middle East or Southeast Asia, we routinely specify the next frame up to absorb this reality.

Earthing and neutral handling

Three-pole versus four-pole selection still confuses procurement teams. For TN-S systems with neutral current under 50% of phase current, three-pole with a neutral CT (the typical Ekip configuration on a 3p F F variant like the ABB 1SDA070861R1 E1.2B 1600 A) is sufficient. For TT systems or where neutral currents exceed 50% of phase due to triplen harmonics, four-pole becomes mandatory per IEC 60364-5-53 §535.4.2.

Standards conformance and type testing

Both the ABB Emax 2 and MasterPact MTZ ranges are tested to IEC 60947-2 for utilization category B (suitable for selectivity under short-circuit conditions). They also carry UL 1066 and ANSI/IEEE C37.13 marks for the North American market — important if your project is engineered to NEC and NEMA conventions but installed elsewhere.

One nuance: the IEC 60947-2 utilization category B test sequence requires the breaker to demonstrate Icw (short-time withstand) at the rated value for 1 second without tripping, then break Icu afterward. Both Emax 2 and MTZ pass this comfortably at 85 kA Icw on the larger frames. NEMA equivalents test slightly differently — the published "withstand" rating in ANSI may not numerically match the IEC Icw, so do not assume direct substitution when reading vendor datasheets prepared for one market and applied in another.

For seismic qualification, ABB publishes IEEE 693 compliance for the Emax 2 mounted in System pro E Power switchgear up to moderate seismic zones. Schneider has equivalent qualification for the MTZ in BlokSeT switchgear. For nuclear-adjacent applications and seismic zone 4 sites, both vendors can supply additional qualification documentation on request, but neither is "qualified out of the box" for those environments.

Related Reading

• What Is the ABB SACE Emax 2? Features, Models and Key Benefits
• ABB Emax 2 Full Technical Specifications: Current Ratings, Breaking Capacity and Dimensions
• ABB Emax 2 vs Siemens 3WL: Breaking Capacity, Digitalization and Total Cost Compared
• ABB Emax 2 in Data Centers: MDB Design, Redundancy and Uptime Considerations

Conclusion: which one should you specify?

There is no universal answer because the right choice depends on voltage class, region, software-licensing tolerance, and the rest of the digital infrastructure on the site. Some engineers argue that any modern ACB will do the job, but in my experience the lifecycle differences emerge clearly by year five or six.

If you are building a 690 V industrial board, integrating with IEC 61850 GOOSE, or running heavy harmonics, the Emax 2 is the safer technical choice and we recommend frames like the ABB 1SDA070741R1 E1.2B 800 A and the ABB 1SDA070781R1 E1.2B 1000 A for typical incomer applications. If you are building a 400 V commercial MDB in a region where Schneider local support is dominant and the digital-module commercial model is acceptable to the end user, the MasterPact MTZ is a solid and well-supported choice.

Specify deliberately. Quote both. Compare TCO, not just unit price. And document the trip-unit settings before you energize, not after the first nuisance trip wakes someone up at 3 a.m. For the complete selection, application, and maintenance methodology covering frame sizing, protection coordination, and commissioning checks, see our ABB SACE Emax 2 engineering guide and the broader air circuit breaker engineering guide.