ABB Emax 2 vs Siemens 3WL Air Circuit Breaker Comparison Guide

What is an ABB Emax 2 vs Siemens 3WL air circuit breaker comparison? An ABB Emax 2 vs Siemens 3WL comparison is a structured evaluation of two IEC 60947-2-compliant low-voltage air circuit breakers rated up to 6300 A, examining how their architecture, trip unit logic, and short-circuit withstand ratings differ across equivalent frame sizes. Selecting the wrong platform for a given application — mismatched Icw ratings, incompatible protection relay ecosystems, or overlooked zone-selective interlocking topology — can compromise coordination studies and extend fault clearance times. This guide covers architectural differences between the two platforms, Ekip versus ETU trip unit capabilities, breaking capacity and short-time withstand performance, real-world application fit, and a head-to-head specification table.

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

Why the Emax 2 vs 3WL Question Comes Up at All

In our experience, the ABB Emax 2 versus 3WL comparison surfaces in three scenarios. A consultant is preparing a tender for an LV main switchboard. A panel builder has been asked to value-engineer an existing design. Or a maintenance manager is sourcing a like-for-like replacement and wants to know if cross-platform substitution is viable. It almost never is, by the way — the cradles, accessories, and trip unit logic do not interchange. But the underlying question is fair: in catalogs, both brands hit nearly identical headline ratings, so what actually separates them?

The honest answer is that the differences live in the details. Trip unit firmware behavior under low-grade arcing faults. Auxiliary contact wiring conventions. Spare parts lead times in your region. The way each brand handles maintenance mode (ARMS for ABB, "reduced let-through" for Siemens). These are the criteria that shape a 20-year ownership experience, not the glossy datasheet.

For complete catalog ratings, dimensions, and trip unit options governing the ABB Emax 2 family, refer to the manufacturer's ABB SACE Emax 2 product portfolio.

Architectural Differences You Will Feel on Site

Both families come in three frame sizes. ABB markets the Emax 2 in three principal frames — E1.2, E2.2, and E4.2 (with E6.2 reserved for very high currents). Siemens uses 3WL Frame I, II, and III. On paper the current bands overlap almost perfectly — the ABB Emax 2 E1.2B at 1600 A maps to a 3WL Frame I at 1600 A. In the cubicle, however, they look and feel different.

Footprint and Cubicle Engineering

The Emax 2 E2.2 is roughly 30 mm narrower than a 3WL Frame II in equivalent ratings. That sounds trivial until you are squeezing eight ACBs into a 2200 mm-wide assembly with cable entry from below. Panel builders working with the ABB 1SDA070981R1 E2.2B 1600 Ekip Dip LI in horizontal rear-connection (HR) configuration consistently report tighter, cleaner busbar runs compared to the equivalent 3WL Frame II.

Drawout Mechanism Philosophy

ABB uses a screw-driven racking system on Emax 2 with three discrete positions: connected, test, and isolated. Siemens uses a similar approach but with a different torque profile — the 3WL needs about 15 N·m of crank effort versus around 12 N·m on the Emax 2 in the connected-to-test transition. Engineers often overlook this until they have racked their twentieth breaker on a hot Saturday during a planned outage. It matters.

Trip Unit Comparison: Ekip vs ETU

This is where the two product lines diverge most sharply. The ABB Emax 2 trip unit lineup — the Ekip family (Dip, Touch, Hi-Touch, G Hi-Touch) — and Siemens' ETU series (ETU200 through ETU800) both implement IEC 60947-2 protection functions, but with different feature segmentation.

Protection Function Granularity

The Ekip Dip LI trip unit fitted to the ABB 1SDA070701R1 E1.2B 630 handles long-time and instantaneous protection — basic, but adequate for downstream feeders. Step up to the Ekip Dip LSI on the ABB 1SDA070782R1 E1.2B 1000 Ekip Dip LSI and you add short-time selectivity, which is non-negotiable for incoming and tie breakers in a coordinated system.

Siemens' ETU200 is roughly equivalent to Ekip Dip LSI. Where the architectures differ is at the higher tiers. Ekip Hi-Touch offers full power quality measurement (THD per harmonic up to the 50th, voltage unbalance, individual phase power factor) while Siemens places similar functionality in the ETU600 and above. In practice the measurement accuracy is similar — both quote ±1% on current per IEC 61557-12 — but the user interfaces are very different.

The Maintenance Mode Question

Arc flash mitigation is now table stakes. ABB calls its solution ARMS (Arc Reduction Maintenance System); Siemens markets a similar function under the term "maintenance mode" with reduced instantaneous pickup. Both reduce incident energy by lowering the instantaneous threshold during work. A common mistake is assuming they behave identically. They do not. ARMS on Emax 2 reverts automatically when the maintenance switch is released; some 3WL configurations require an explicit ETU command. For an arc-flash-conscious facility — which is to say, every facility working under NFPA 70E or IEEE 1584 — auto-revert is a meaningful safety advantage.

For a deeper look at trip unit behavior in real installations, see the article on ABB Emax 2 nuisance tripping causes and solutions, which covers ground-fault sensitivity issues that apply (with different thresholds) to both brands.

Breaking Capacity and Short-Time Withstand

Both lines hit the headline numbers at 415 V AC. ABB Emax 2 E1.2B is rated Icu = 42 kA; the 3WL Frame I in equivalent class hits 42 kA as well. The differences emerge at higher voltages and in the short-time withstand current rating (Icw), which governs whether a breaker can hold in for the time delay needed for downstream selectivity.

For a 50 kA prospective fault with a 0.4 s short-time delay, the Icw required is roughly 31.6 kA. The Emax 2 E2.2B holds 42 kA Icw for 1 s — comfortably above. The 3WL Frame II at the equivalent rating holds 50 kA for 1 s in some configurations, which gives Siemens a small edge in coordination headroom for very stiff networks. For most industrial applications, both pass. For utility intertie or large generator paralleling, run the numbers carefully against the actual prospective fault.

Head-to-Head Specification Table

The table below benchmarks comparable ABB Emax 2, Siemens 3WL, and Schneider MasterPact MTZ models across three frame classes. Values are taken from current manufacturer catalogs at 415 V AC, three-pole, fixed mounting.

Real-World Application Scenarios

Data Center Main Distribution Board

For a 2 MW data center MDB feeding multiple PDUs, the typical incoming ACB lands around 2500–3200 A. Tier III and Tier IV designs require 2N redundancy at the MDB level, which means breaker reliability and selectivity matter more than absolute breaking capacity. ABB has invested heavily in IEC 61850 GOOSE messaging on Ekip Touch trip units, which streamlines fast bus-transfer schemes between A and B feeds. We covered this in detail in the analysis of ABB Emax 2 in data centers — MDB design and uptime considerations. Siemens supports the same protocol but the implementation maturity in the field, in our experience, is slightly behind ABB as of late.

Oil and Gas Onshore Facility

A 6.6 kV / 415 V LV switchgear at an onshore terminal needs ACBs that survive ambient temperatures up to 50 °C without derating. Both brands publish detailed thermal derating curves. The Emax 2 with the standard horizontal busbars holds full rating to 40 °C and derates linearly to about 90% at 55 °C. The 3WL is similar but in some configurations starts derating at 35 °C. For procurement teams sourcing for hot-climate sites, this curve check is essential — and it is the kind of detail buried in datasheet appendix C that is easy to miss.

Generator Paralleling Switchgear

For a generator main breaker rated 800–1000 A, both ABB 1SDA070741R1 E1.2B 800 and ABB 1SDA070781R1 E1.2B 1000 are common choices. Siemens equivalents are 3WL1108 and 3WL1110. The reverse-power and loss-of-field protection functions are usually handled by an external relay (e.g., ABB REG670 or Siemens 7UM62), so the ACB itself is doing standard LSI plus shunt and undervoltage release. Here, the choice often defaults to whatever the genset OEM has standardized on.

Lifecycle, Spares, and Total Cost of Ownership

This is the section that procurement managers care about most. Both ABB and Siemens guarantee spare parts availability for 10 years post-discontinuation, which is the IEC standard expectation. In practice, both honor this. Where the brands differ is in regional stocking depth.

Spares Lead Time Reality

Trip units, racking handles, and auxiliary contacts are typically stocked locally for both brands in major industrial regions (Europe, North America, Gulf, East Asia). Frames, racking cradles, and arc chutes are not — those ship from a regional warehouse and can take 4–8 weeks. For a critical site, this means stocking at least one spare frame regardless of brand. Some engineers argue Siemens has a small edge in Germany and Central Europe; in our experience, ABB's Italian production base gives it slightly better lead times in the Mediterranean and Middle East. Your regional reality should drive the decision.

Trip Unit Obsolescence

ABB has been aggressive in updating the Ekip family — Ekip Touch firmware has gone through several major revisions since 2018. Siemens has been more conservative, which some maintenance teams prefer because it means less retraining. Neither approach is wrong; it is a question of organizational culture.

Pricing Bands

List prices for comparable units (e.g., 1600 A frame with LSI trip unit, fixed-mount, three-pole) sit within roughly 8% of each other globally. After distributor discounts, the delivered price gap usually narrows further. We have seen tenders where Siemens won by 3% and others where ABB won by 5%. Anyone telling you one brand is consistently cheaper is selling you something.

Communication and Digital Integration

Both brands fully support modern industrial protocols: Modbus RTU and TCP, Profibus DP, Profinet IO, and IEC 61850. The ABB 1SDA070861R1 E1.2B 1600 with an Ekip Com Hub gateway can stream up to 200 measurement points to a SCADA system. The 3WL with COM35 module delivers similar functionality. Where they diverge is in the cloud integration layer — ABB Ability Electrical Distribution Control System and Siemens Powerys Connect Box. Both require subscriptions. Both promise predictive maintenance. In our field experience, the value extracted depends entirely on whether the maintenance team will actually look at the dashboards.

For the broader feature set, the article on what the ABB SACE Emax 2 is, its features and key benefits walks through the digital ecosystem in more depth.

Sizing and Selection Methodology

Whether you choose Emax 2 or 3WL, the selection process is the same. Determine the load current, apply ambient and harmonic correction factors, verify the prospective short-circuit current is below Icu, confirm Icw supports your selectivity time, and check mechanical endurance against expected operating cycles. The detailed walkthrough is in how to size ABB Emax 2 with a step-by-step calculator, and the framework applies equally to Siemens 3WL.

For the underlying ratings — including the temperature derating curves and dimensional drawings — see the full ABB Emax 2 technical specifications, ratings and dimensions reference.

When the Comparison Includes Schneider

Frequently the choice is not two-way but three-way: ABB, Siemens, and Schneider MasterPact MTZ. The MTZ shares more with Emax 2 than with the 3WL in terms of trip unit philosophy and physical layout. We treat the Schneider comparison separately in the dedicated ABB Emax 2 vs Schneider MasterPact MTZ technical comparison, but the short summary is: MTZ is closer to Emax 2 in feel, while 3WL is the more distinctive option of the three.

Practical Selection Checklist

If you are still on the fence after reviewing both datasheets, here is the discriminating question set we use in switchgear design reviews:

What is the existing brand standard at this site? Which brand has a service center within 200 km? What are the regional spares stocking commitments in writing? Is IEC 61850 GOOSE messaging required for fast bus transfer? Will the maintenance team be trained on the trip unit interface, and which interface do they already know? Is arc-flash maintenance mode auto-revert a regulatory requirement on this site? What does the genset OEM's ATS specify?

Answer those seven questions and the decision usually makes itself. If the answers point both directions, default to the brand you have more of in the rest of the gear. Standardization wins.

Browse the full

Browse the full air circuit breakers collection at Stoklink for available frames and trip unit configurations from both manufacturers, along with cross-references for legacy units. For downstream feeder protection that coordinates with these ACBs, the miniature circuit breaker collection and residual current device collection cover the smaller end of the protection chain.

Field Notes from Recent Projects

Three quick observations from projects we have specified or commissioned in the last 18 months. They are not statistically significant. They are honest field experience.

First, on a 1.8 MW pharmaceutical facility in Ireland, the design team initially specified 3WL for a tie breaker and Emax 2 for the incomers because of legacy stock. The mixed fleet caused trouble during commissioning when the SCADA integrator had to maintain two separate device libraries and two protocol mappings. The cost overrun on engineering hours wiped out the perceived spare-parts savings. Lesson: standardize.

Second, at a Saudi petrochemical plant we observed a 3WL trip unit fail intermittently due to dust ingress through a poorly sealed cubicle. The replacement ETU was on a 6-week lead time. The site had no spare. After that experience the operator switched future orders to Emax 2 — not because Emax is more dust-resistant (both are IP54 with proper enclosures), but because their regional ABB partner held local stock of Ekip trip units. Logistics, not technology, drove the decision.

Third, on a UK data center retrofit, the customer wanted IEC 61850 GOOSE for fast source transfer between two 2500 A incomers. The Emax 2 with Ekip G Hi-Touch handled it cleanly. The 3WL quote on the alternative tender required an external IEC 61850 gateway, adding cost and complexity. For that specific use case, Emax 2 was the simpler engineering solution.

Accessory Ecosystem and Auxiliary Devices

Both ACB families support a comparable set of accessories: shunt trip coils, undervoltage releases, motor operators, mechanical interlocks, key locks, and auxiliary contact blocks. The wiring conventions differ. ABB uses a numbered terminal block that maps directly to the wiring diagram in the catalog. Siemens uses a similar approach with slightly different terminal numbering. Engineers who have wired one brand for years will fumble the first few cabinets of the other. Plan for that learning curve in your project schedule.

For control circuit components downstream — interposing relays, timers, latching relays for ATS logic — both ABB and Siemens offer broad portfolios. The relay collection covers the most common interposing devices used alongside ACB control circuits.

Motor Operators and Spring Charging

Motor operators are rated for endurance in operations per hour. Emax 2 motor operators are typically rated for 60 ops/hour continuous; 3WL operators sit in the same band. For a transfer scheme that may operate dozens of times during a utility disturbance, that endurance number matters. Both brands derate when operated at the upper limit of their voltage range (usually 110 V DC ±15%), so size your control transformer or DC battery accordingly.

Standards Compliance Snapshot

Both Emax 2 and 3WL are tested and certified to:

IEC 60947-1 (general rules for low-voltage switchgear), IEC 60947-2 (circuit breakers), IEC 61000-4 series (EMC), IEC 60068-2 (environmental tests), and where applicable UL 1066 / UL 489 for North American applications. NEMA AB 4 guidelines for field inspection apply to both. IEEE C37.13 covers the broader category of low-voltage power circuit breakers and is referenced in many North American specifications. If your project is in the United States, verify the specific UL listing rather than assuming the IEC certification translates — it usually requires a separately listed variant.

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 Schneider MasterPact MTZ: Technical Specs, Features and Price Compared
• ABB Emax 2 in Data Centers: MDB Design, Redundancy and Uptime Considerations

Conclusion

The Emax 2 versus 3WL decision is, at its core, a question about ecosystem fit rather than electrical performance. Both families meet IEC 60947-2 with margin. Both support modern protocols. Both have decade-plus spare parts commitments. The difference is in cubicle dimensions, trip unit user experience, regional logistics, and how each brand integrates with the rest of your facility's electrical fleet. Senior engineers we trust have specified both successfully on projects from 400 A feeders to 6300 A incomers. The wrong choice is the one made on price alone, ignoring the 25-year ownership cost.

For the complete selection framework — including derating curves, accessory selection, and commissioning checklists — return to the ABB SACE Emax 2 selection, application and maintenance guide as your reference document. And when the specifications are locked, the air circuit breaker portfolio at Stoklink covers the full Emax 2 catalog from E1.2 through E4.2 with stock available for the most common frame and trip unit combinations.