ABB SACE Emax 2 Technical Specifications, Ratings and Dimensions Guide
What is the ABB SACE Emax 2? The ABB SACE Emax 2 is an electronically controlled air circuit breaker family rated 400–6300 A at up to 1000 V AC under IEC 60947-2, offering breaking capacities (Icu) up to 200 kA and short-time withstand currents (Icw) up to 100 kA for 1 second. Misreading the catalog code, selecting an incorrect frame size, or overlooking Ics derating factors can result in underprotected busbars, failed type-test compliance, or costly mid-project substitutions. This guide covers Emax 2 frame sizes and current ratings, Icu/Ics/Icw definitions and selection logic, physical dimensions and mounting envelopes, catalog code decoding, real-application sizing methodology, and accessory and communication option specification.
What Are the Frame Sizes and Current Ratings of the Emax 2 Family?
The ABB Emax 2 range is built around four mechanical frames: E1.2, E2.2, E4.2, and E6.2. Each frame covers a defined current band, and within each frame ABB offers performance classes (B, N, S, H, V, L, X) that determine the rated ultimate short-circuit breaking capacity Icu. This two-axis structure — frame size by current, performance class by Icu — is the core of how you specify an Emax 2.
In our experience, the most common mistake at tender stage is treating the frame and the performance class as one selection. They are not. A 1600 A breaker can sit in an E1.2 frame (compact, up to 66 kA) or in an E2.2 frame (taller, up to 100 kA) depending on the upstream fault level. Picking the wrong combination either wastes panel space or, worse, leaves the breaker undersized for the prospective short-circuit current.
Frame and Rated Current Overview
The E1.2 frame covers 630 A to 1600 A. Typical SKUs include the ABB 1SDA070701R1 E1.2B 630 Ekip Dip LI for sub-distribution feeders and the ABB 1SDA070861R1 E1.2B 1600 Ekip Dip LI for incomers in mid-size MCCs. E2.2 covers 800 A to 2500 A and is the workhorse for transformer secondaries up to 1600 kVA. E4.2 covers 3200 A to 4000 A and is the typical choice for 2500 kVA transformer feeders. E6.2 reaches 6300 A and is reserved for very large incomers, paralleling schemes, and bus-tie applications in heavy industry.
Technical specifications and ratings for the ABB Emax 2 air circuit breaker family are defined in accordance with IEC 60947-2 Low-voltage switchgear standard.
How Are Breaking Capacities (Icu, Ics, Icw) Defined and Selected?
IEC 60947-2 specifies three short-circuit ratings that engineers must understand to select an ABB Emax 2 correctly. Icu is the rated ultimate short-circuit breaking capacity — the maximum prospective fault current the breaker will interrupt once and remain safe to isolate, but not necessarily fit for further service. Ics is the rated service short-circuit breaking capacity, expressed as a percentage of Icu (typically 100% for Emax 2), meaning the breaker remains fully serviceable after the interruption. Icw is the rated short-time withstand current — the current the breaker can carry for a defined time (usually 1 s or 3 s) without tripping, which is critical for selectivity with downstream devices.
Engineers often overlook Icw. In a typical industrial switchboard, you need the upstream incomer to delay tripping by 200–400 ms while a downstream feeder clears its fault. If the incomer's Icw is lower than the let-through energy during that delay, you lose discrimination — the main breaker trips with the feeder, blacking out the entire board. The Emax 2 E2.2N at 1600 A, for example, offers Icw = 42 kA for 1 s, which is enough to coordinate with most MCCBs operating at sub-cycle clearing times.
Performance Classes Compared
| Criteria | E1.2B (Basic) | E2.2N (Normal) | E4.2H (High) |
|---|---|---|---|
| Rated current band | 630–1600 A | 800–2500 A | 3200–4000 A |
| Icu @ 415 V AC | 42 kA | 66 kA | 100 kA |
| Ics (% of Icu) | 100% | 100% | 100% |
| Icw (1 s) | 42 kA | 66 kA | 85 kA |
| Typical application | Sub-distribution, generator backup | Transformer secondary up to 1600 kVA | Main incomer, 2500 kVA transformer |
| Frame width (3P) | 324 mm | 404 mm | 566 mm |
For deeper discussion of test sequences and certifications behind these numbers, the article on ABB Emax 2 IEC 60947-2 Compliance: Standards, Type Tests and Certifications walks through the O-CO-CO sequence and how Ics is verified.
Formula: Prospective Short-Circuit Current at Transformer Secondary — Source: IEC 60909-0 §6.2
Ik = (Sn × 100) / (√3 × Un × uk)
| Symbol | Description | Unit |
|---|---|---|
| Ik | Three-phase short-circuit current | kA |
| Sn | Transformer rated apparent power | kVA |
| Un | Rated line-to-line voltage | V |
| uk | Short-circuit impedance | % |
For a 2000 kVA, 400 V, 6% uk transformer: Ik ≈ 48 kA. An E2.2N at 66 kA Icu gives a 37% safety margin, which is healthy. An E1.2B at 42 kA would be undersized — a real example we saw in a Middle East petrochemical project where a value-engineered substitution caused a re-tender at procurement.
What Are the Physical Dimensions and Mounting Envelopes?
Panel space drives more selection decisions than most engineers admit. The ABB Emax 2 frames have well-defined external envelopes that must be respected for arc venting, ventilation, and accessory clearance. Both fixed (F) and withdrawable (W) versions exist, with the withdrawable version adding roughly 80–120 mm to the depth because of the cassette.
Frame Dimensions (Fixed, 3-Pole)
| Frame | Width (mm) | Height (mm) | Depth (mm) | Weight (kg, approx.) |
|---|---|---|---|---|
| E1.2 | 324 | 302 | 277 | 32 |
| E2.2 | 404 | 302 | 277 | 45 |
| E4.2 | 566 | 422 | 302 | 78 |
| E6.2 | 746 | 422 | 302 | 120 |
For 4-pole versions, add roughly 100 mm to the width on E1.2 and E2.2, and 130 mm on E4.2/E6.2. Withdrawable versions add the cassette: typically +90 mm depth on E1.2/E2.2 and +110 mm on E4.2/E6.2. The 1000 A withdrawable variants such as the ABB 1SDA070782R1 E1.2B 1000 Ekip Dip LSI are popular in projects where future serviceability matters more than initial panel cost.
Clearance and Arc Venting
ABB specifies a minimum 50 mm clearance above the breaker for arc venting on E1.2/E2.2 and 100 mm on E4.2/E6.2. In switchgear designs tested to IEC 61439-1/2, this clearance becomes part of the form-segregation strategy. A common mistake is to bolt the breaker directly under a horizontal busbar trunking with only the catalog minimum — which works on paper but fails the internal arc fault test (IEC 61641 / IEC TR 61641) because the gas plume hits the busbar insulation.
How Do You Read the Emax 2 Catalog Code?
The ABB ordering code looks intimidating but follows a strict logic. Take 1SDA070741R1: this is the order number for an E1.2B 800 A, 3-pole, fixed, with horizontal rear terminals and Ekip Dip LI trip unit. Once you decode the pattern, you can read any ABB Emax 2 SKU at a glance.
The format is: [Frame].[Class] [In] [Trip unit] [Poles] [Mounting] [Terminals]. So ABB 1SDA070981R1 E2.2B 1600 Ekip Dip LI 3p F HR reads as: E2.2 frame, B class (42 kA), 1600 A In, Ekip Dip with LI protection, 3-pole, Fixed mounting, Horizontal Rear terminals.
Trip Unit Codes
Ekip Dip is the entry-level digital trip unit. Suffixes describe protection functions: LI = Long-time + Instantaneous, LSI = adds Short-time delay, LSIG = adds Ground fault. For most distribution applications, LSI is the practical minimum because it enables time-graded selectivity. LI alone trips instantaneously on any short-circuit, which destroys discrimination with downstream MCCBs. We typically see LI specified only for generator protection or end-feeder service where no downstream coordination is needed.
For higher functionality, Ekip Touch and Ekip Hi-Touch trip units add measurement, communication (Modbus, Profibus, Profinet, IEC 61850), and advanced protection (directional, voltage, frequency). The overview of Emax 2 features and models covers the full Ekip family.
How Should Engineers Size an Emax 2 for a Real Application?
Sizing an ABB Emax 2 is more than picking a current rating. You need to evaluate continuous load, harmonic content, ambient temperature, altitude, prospective fault current, and selectivity requirements. The continuous load calculation alone has caused more nuisance trips than any other single error.
In a recent data center project we reviewed, the design team specified an E1.2B 1000 A on a UPS bypass feeder that was carrying 880 A continuous in a 45 °C switchgear room. The breaker is rated for 40 °C ambient. At 45 °C, the In must be derated by approximately 5%, giving 950 A effective — uncomfortably close to the actual load. After three months, the bimetal in the trip unit drifted, nuisance trips started, and the operator blamed the breaker. The fault was sizing.
Ambient Temperature Derating
Formula: Temperature-Corrected Current Rating — Source: ABB Emax 2 Technical Catalog (consistent with IEC 60947-2 §7.2.1)
In,corr = In × kθ
| Symbol | Description | Unit |
|---|---|---|
| In,corr | Corrected rated current | A |
| In | Rated current at 40 °C | A |
| kθ | Temperature derating factor (1.00 at 40 °C, 0.95 at 50 °C, 0.90 at 60 °C) | — |
For a more comprehensive sizing workflow including selectivity studies and cable coordination, the dedicated step-by-step sizing calculator for LV distribution panels walks through worked examples.
Altitude Derating
Above 2000 m the dielectric strength of air decreases. ABB specifies derating of both rated voltage and current above 2000 m. At 3000 m, Ue drops from 690 V to about 600 V, and In drops by roughly 2%. For Andean mining projects (Peru, Chile) at 4000 m elevation, you may need to step up one performance class to retain margin. This is documented in the Emax 2 technical catalog and aligns with IEC 60947-1 §7.1.2.
What Accessories and Communication Options Should You Specify?
Accessories drive the wiring and the panel layout, and they are frequently forgotten until the ABB Emax 2 breaker is on site. The main categories are: auxiliary contacts (AUX), shunt trip (YO), undervoltage release (YU), closing coil (YC), motor operator (M), and mechanical interlocks. For automated transfer schemes, the motor operator and the closing coil are non-negotiable.
For communication, Ekip Touch supports Modbus RTU as standard. Add the Ekip Com module for Modbus TCP, Profibus DP, Profinet, EtherNet/IP, or IEC 61850. In data center applications, IEC 61850 is increasingly mandated for integration with the substation automation system. The data center MDB design guide discusses redundancy and protocol selection in more detail.
Common Accessory Combinations
For a typical incoming breaker with auto-transfer logic, you'll need: 4 NO + 4 NC AUX contacts, YO shunt trip (24 V DC for control system tripping), YC closing coil, M motor operator, and an Ekip Com Modbus TCP module. Budget approximately 18–25% of the breaker base price for accessories — engineers and procurement teams routinely under-allocate this.
How Do Emax 2 Specs Compare to Competitors?
The closest competitor is the Schneider MasterPact MTZ family. Both meet IEC 60947-2, both reach 6300 A, both offer 100 kA performance classes. Mechanically and electrically they are peers. The differences emerge in trip unit ergonomics, communication ecosystems, and spare parts logistics in your region. We discuss the head-to-head in ABB Emax 2 vs Schneider MasterPact MTZ: Technical Specs, Features and Price Compared.
Some engineers argue Schneider's Micrologic X has a better touchscreen UI; others prefer ABB Ekip Touch for its connectivity options and the Ekip Bluetooth interface for commissioning. In my experience the deciding factor is rarely the trip unit — it's whether your standard panel builder is already tooled for one brand. Switching brands mid-project costs more than any spec advantage justifies.
Beyond the Emax 2, Stoklink stocks the broader range of air circuit breakers, miniature circuit breakers, residual current devices, and protection relays needed for a complete LV distribution build.
What Are Common Field Issues with Emax 2 Specifications?
Three issues recur in ABB Emax 2 commissioning reports. First, undersized neutral on 4-pole breakers serving non-linear loads — VFDs and LED lighting create third-harmonic currents that flow back in the neutral. The neutral conductor and the breaker's neutral pole need to be rated 100% (not 50%, which is an option on some configurations). Second, mis-set Ekip Dip thresholds at handover. The factory default is rarely correct for the actual installation. Third, accessory wiring done with insufficient cross-section, leading to voltage drops on long shunt-trip runs.
For systematic diagnostics on tripping issues that appear weeks or months after commissioning, see ABB Emax 2 Nuisance Tripping: Root Causes, Diagnostic Steps and Fixes.
One specific case worth mentioning: on a 1250 A feeder using the ABB 1SDA070821R1 E1.2B 1250 Ekip Dip LI, the commissioning team left the L pickup at the default 1.0 × In. The actual continuous load was 1180 A with brief 1240 A peaks during morning startup. The breaker tripped on long-time protection three days in a row before someone reviewed the settings. Adjusted to 1.05 × In with a t1 delay aligned to the load profile, the problem disappeared. Settings matter as much as hardware.
How Do You Verify Emax 2 Compliance During Factory Acceptance?
Factory Acceptance Testing (FAT) for switchgear containing ABB Emax 2 breakers should verify three things at minimum: rating plate against the Bill of Materials, trip unit settings against the protection coordination study, and accessory operation against the wiring diagram. The Ekip Bluetooth or Ekip Connect software lets you download the actual settings into a PDF report — keep this with the project handover documents.
The primary injection test is the gold standard but expensive. Most projects rely on secondary injection through the Ekip T&P test unit, which simulates current at the trip unit input and verifies the algorithm's response. This catches setting errors but not CT wiring errors. For critical applications — utility substations, hospitals, data centers — primary injection is worth the day of testing.
Routine and Type Test References
IEC 60947-2 Clause 8.3 defines routine tests every breaker undergoes at the factory: mechanical operation, dielectric verification at 2 × Ue + 1000 V, and trip unit calibration check. Type tests under Clause 8.3.4 (short-circuit performance, temperature rise, mechanical endurance) are performed on representative samples and documented in the type-test certificate. Always request the type-test certificate from your supplier — for the Emax 2, ABB makes these available on request and they reference KEMA, CESI, or IPH laboratory reports.
Related Reading
- What Is the ABB SACE Emax 2? Features, Models and Key Benefits
- ABB Emax 2 IEC 60947-2 Compliance: Standards, Type Tests and Certifications
- How to Size ABB Emax 2: Step-by-Step Calculator for LV Distribution Panels
- ABB Emax 2 vs Schneider MasterPact MTZ: Technical Specs, Features and Price Compared
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Frequently Asked Questions
What is the maximum breaking capacity of the ABB SACE Emax 2?
The Emax 2 reaches Icu = 200 kA at 415 V AC in the X performance class on E2.2 and E4.2 frames, although the more common high-end is 100 kA in the H class. Icu and Ics are equal (Ics = 100% of Icu) across the entire range, which is rare in the LV breaker market and an advantage for service continuity. Always check the type-test certificate for your specific frame and class combination.
What is the difference between Emax 2 fixed and withdrawable versions?
Fixed versions are bolted to the panel and require disconnection of cables for breaker replacement. Withdrawable versions sit in a cassette, allowing the breaker to be racked out for maintenance without disturbing the wiring — useful for critical installations where downtime is expensive. Withdrawable adds approximately 90–110 mm of depth and 25–35% to the unit cost. For details on selection trade-offs, the Emax 2 selection and maintenance guide covers this in depth.
Can I use an E1.2B for a 1600 A application above 42 kA fault current?
No. The E1.2B is rated 42 kA Icu at 415 V, which is the maximum it can interrupt. If your prospective fault current exceeds 42 kA, step up to E1.2N (50 kA) or move to E2.2N (66 kA) on the same 1600 A In. The ABB 1SDA070861R1 E1.2B 1600 is appropriate for sub-distribution where upstream impedance limits Ik.
What ambient temperature is the Emax 2 rated for?
The standard rating is at 40 °C ambient inside the switchgear, per IEC 60947-2. Operation up to 70 °C is permitted with current derating: roughly 5% reduction at 50 °C, 10% at 60 °C, and 15% at 70 °C. Storage range is −40 °C to +70 °C. For switchgear in hot climates without HVAC, always assume internal temperatures 10–15 °C above the room ambient.
How do I select between Ekip Dip, Ekip Touch, and Ekip Hi-Touch?
Ekip Dip is sufficient for standard distribution where you only need protection (LI, LSI, or LSIG). Ekip Touch adds measurement (current, voltage, power, energy), Modbus communication, and a graphical display — choose this when the breaker is part of an energy management or SCADA system. Ekip Hi-Touch adds advanced protections (directional, voltage, frequency, synchrocheck) for generator and bus-coupling applications. For nuanced trip unit issues, see the article on nuisance tripping diagnostics.
What is the mechanical and electrical endurance of the Emax 2?
Mechanical endurance is 12,500 operations on E1.2 and E2.2, 10,000 on E4.2, and 5,000 on E6.2 (without maintenance, per IEC 60947-2 Clause 7.2.4.3). Electrical endurance at rated current ranges from 6,000 cycles (E1.2) down to 1,500 cycles (E6.2). For frequent switching applications such as motor breakers or capacitor banks, plan a maintenance interval at 50% of the mechanical endurance figure.
Conclusion
Specifying the ABB SACE Emax 2 correctly comes down to four disciplined choices: the right frame for the current, the right performance class for the fault level, the right trip unit for the protection scheme, and the right accessories for the operating logic. Get any of these wrong and you either overpay at procurement or pay later in nuisance trips, retrofit work, and lost production. The good news is that the Emax 2 catalog, once decoded, gives you a coherent matrix that scales from a 630 A feeder like the E1.2B 630 Ekip Dip LI to a 2000 A incomer like the ABB 1SDA071021R1 E2.2B 2000 Ekip Dip LI with consistent dimensions, accessories, and trip unit logic across the range.
For the full selection methodology — including coordination studies, maintenance planning, and procurement strategies — see the comprehensive ABB SACE Emax 2 Air Circuit Breaker: Selection, Application and Maintenance Guide. When in doubt, specify one performance class above your calculated requirement: the cost difference is small, and the operational margin pays for itself the first time fault levels grow with a system upgrade.
