ABB Emax 2 Preventive Maintenance Procedure and Schedule Guide
What is an ABB Emax 2 preventive maintenance procedure? An ABB Emax 2 preventive maintenance procedure is a structured inspection and servicing regimen for open air circuit breakers rated 400–6300 A under IEC 60947-2, encompassing mechanical verification, contact wear assessment, arc chute inspection, Ekip trip unit testing, and lubrication at defined intervals to sustain rated breaking capacity up to 150 kA. Deferred or improperly executed maintenance invalidates ABB's performance guarantees, accelerates contact erosion, and risks undetected trip unit drift that leaves downstream equipment unprotected during fault events. This guide covers mandatory IEC and ABB maintenance intervals, Level 1 through Level 3 field procedures, arc chute and contact wear thresholds, Ekip trip unit verification methods, and a spare parts procurement strategy.
Why Preventive Maintenance on an Emax 2 Is Not Optional
A common mistake is treating an air circuit breaker (ACB) as a "fit and forget" device. It isn't. The ABB Emax 2, like every low-voltage air circuit breaker, contains a spring-charged operating mechanism, silver-tungsten arcing contacts, an arc chute stack, secondary disconnects, and a microprocessor-based Ekip trip unit. Each of these ages differently. The mechanism wears with operations; the contacts erode with every fault interruption; the arc chutes accumulate ionised metal vapour deposits; the Ekip's internal supercapacitor and rogowski coils drift over time.
IEC 60947-2 §8.3 and IEEE C37.20.1 both treat scheduled maintenance as a precondition for the manufacturer's published endurance figures. ABB's own catalogue values — for example, 12,500 mechanical operations and 10,000 electrical operations at Ie for an E1.2 — assume the device is being inspected and lubricated at the prescribed intervals. Skip the schedule and you forfeit those numbers.
In our experience auditing data centres and process plants across Europe and the Gulf, roughly one in four nuisance trips on Emax-class breakers traces back to a missed inspection — typically a contaminated arc chute, a stiff secondary contact, or a trip unit running on a depleted backup capacitor. The cost of a 4-hour PM visit is trivial compared to one unplanned outage on a tier-III data centre busbar, which is precisely why facilities running Emax 2 in data center MDB designs treat PM as a non-negotiable line item.
For complete technical specifications and maintenance requirements of the ABB Emax 2 air circuit breaker family, refer to the ABB SACE Emax 2 product documentation, which details rated performance values, mechanical and electrical endurance, and prescribed inspection intervals aligned with IEC 60947-2.
Maintenance Intervals: What ABB and IEC Actually Require
ABB classifies Emax 2 maintenance into four levels, and the interval depends on three variables: number of operations, ambient conditions, and load profile. The published baseline for the ABB Emax 2 assumes a "normal" environment — indoor switchgear, 35 °C ambient, less than 50 % humidity, low dust. Anything outside that window compresses the schedule.
Standard Schedule for Normal Service Conditions
| Level | Interval (whichever first) | Scope | Outage required |
|---|---|---|---|
| L1 — Visual | 6 months or 1,750 ops | External inspection, indicator check, Ekip self-test log review | No |
| L2 — Functional | 12 months or 2,500 ops | Mechanical operation test, secondary disconnects, racking mechanism | Yes (breaker open, racked out) |
| L3 — Detailed | 5 years or 5,000 ops | Arc chute removal, contact wear measurement, lubrication, trip unit injection test | Yes (full isolation) |
| L4 — Overhaul | 10 years or at end of electrical life | Contact replacement, mechanism overhaul, full recalibration | Yes (workshop) |
Adjustments for Harsh Environments
For harsh service — coastal sites, cement plants, offshore platforms, anywhere with H2S, salt mist, or conductive dust — halve the L1 and L2 intervals. A 1600 A ABB 1SDA070861R1 E1.2B 1600 Ekip Dip LI running on a desalination plant in the UAE will accumulate enough salt deposit on the secondary disconnects in 4 months to cause intermittent auxiliary contact failure. We've seen it. The fix is a quarterly L1 with contact cleaning, not the standard 6-month visit.
Conversely, breakers operating well below their rated current — say, an ABB 1SDA070781R1 E1.2B 1000 A loaded to 350 A average — accumulate fewer thermal cycles and can safely stretch the L3 interval by 12–18 months, provided the operations counter and Ekip event log support that decision.
Level 1 and Level 2 Procedures: What to Actually Do
Engineers often overlook how much a competent L1 inspection on an ABB Emax 2 catches without ever opening the cubicle. Here's the procedure we use, adapted from ABB document 1SDH001000R0002 and aligned with IEEE 3007.2-2010 §6.3.
L1 Visual Inspection (Energised, No Outage)
With the breaker closed and on load, walk the front panel. Check the mechanical state indicators: spring charged or discharged, breaker open or closed, ready-to-close. Read the Ekip touch display: confirm no active alarms, review the last 20 events, note the operations counter and the cumulative I²t figure. Verify the trip unit's auxiliary supply LED. Thermographic scan the line and load terminals through the IR window — anything above 65 °C delta over ambient is a flag, anything above 90 °C absolute on the busbar joint is an immediate work order.
Listen. A healthy Emax 2 is silent. A buzzing or chattering sound from the closing solenoid points to a low-voltage condition on the YC coil, which on a 230 V AC supply means anything below roughly 195 V (85 % of Un per IEC 60947-2 §7.2.1.2).
L2 Functional Test (Breaker Racked Out, Cubicle De-energised)
Rack the breaker to the test position. Verify the racking handle torque — ABB specifies 8 N·m maximum on E1.2/E2.2 and 12 N·m on E4.2/E6.2. Excessive force here is the single most common cause of cluster contact damage on the primary disconnects. Operate the breaker manually 5 times using the closing pushbutton and the trip pushbutton. Observe spring charging time: typically 4–5 seconds on the geared motor operator. Anything beyond 7 seconds indicates a worn motor or a binding gearbox.
Test the trip unit. Use the Ekip TT test unit or the Ekip Bluetooth dongle to inject a simulated overcurrent and verify the trip occurs within tolerance. Per IEC 60947-2 Annex F, the long-time delay (L) function must trip within ±10 % of the set time at 6 × Ir. Document the result. If you don't write it down, the audit says you didn't do it.
Level 3: Contact Wear, Arc Chute, and Lubrication
This is where most maintenance teams get nervous, and rightly so. L3 requires opening the breaker, and a poorly executed L3 on an ABB Emax 2 can introduce more faults than it prevents. We recommend two technicians, an ESD-safe workspace, and an ABB-certified service kit.
Measuring Contact Wear
The Emax 2 uses a sacrificial arcing contact that erodes with each interruption. ABB provides a wear indicator on the moving contact carrier — a coloured band that becomes visible when wear reaches the replacement threshold. But the indicator alone isn't enough. For audit-grade documentation, measure the contact gap with a feeler gauge after the arc chutes are removed.
Formula: Cumulative Electrical Wear Estimate — Source: IEC 60947-2 Annex M, indicative
We = Σ (Ifault,i / In)2 × tarc,i
| Symbol | Description | Unit |
|---|---|---|
| We | Cumulative electrical wear index | p.u.·s |
| Ifault,i | RMS interrupted current of event i | A |
| In | Rated uninterrupted current of breaker | A |
| tarc,i | Arcing time of event i | s |
The Ekip trip unit logs each interruption with the I²t value, which makes this calculation straightforward in software. When We approaches the manufacturer's threshold (typically expressed as remaining electrical operations < 20 %), schedule contact replacement at the next planned outage. Don't wait for it to fail.
Arc Chute Inspection
Remove the arc chutes. Inspect the splitter plates for cracks, melted edges, or heavy carbon deposits. Light grey discolouration is normal — it's just the residue of normal interruption. Black carbonisation, blistering, or any deformation means the chute has interrupted near its design limit and must be replaced. On an E2.2 frame like the ABB 1SDA070981R1 E2.2B 1600, the arc chute kit is part number 1SDA0xxxxxR1 (consult current ABB spares list) and is replaced as a pole assembly, not as individual plates.
Lubrication Points
Use only ABB-specified greases. The closing/opening mechanism uses Mobilgrease 28 or equivalent low-temperature synthetic; the racking screw uses Molykote D321R dry film. A common mistake is applying generic lithium grease — it works for six months, then it gums up at low temperature and the closing time doubles. We've recovered breakers from a substation in Kazakhstan where this exact error caused failure-to-close at –15 °C.
Trip Unit Verification: The Ekip Dip and Beyond
The Ekip trip unit is the brain of the ABB Emax 2, and it deserves its own attention. The Ekip Dip — the basic LI variant fitted on devices like the ABB 1SDA070701R1 E1.2B 630 and the ABB 1SDA070741R1 E1.2B 800 — provides long-time and instantaneous protection. Higher-end Ekip Touch and Ekip Hi-Touch units add LSIG, measurement, and communication functions.
Verification has two layers. First, the self-test: every Ekip unit performs an internal diagnostic on every operation and stores faults in the event log. Read the log. Second, the secondary injection test: apply a calibrated current to the trip unit's test port and verify the trip time matches the curve within IEC 60947-2 tolerance bands.
For LSI units like the ABB 1SDA070782R1 E1.2B 1000 Ekip Dip LSI, also verify the short-time delay (S) function — typically set between 0.05 s and 0.4 s, and frequently the source of selectivity problems if drift occurs. We see S-function drift more often than L-function drift, probably because the short-time circuit involves more analog conditioning. If you're chasing intermittent upstream trips, see our companion article on Emax 2 nuisance tripping causes and solutions before blaming the load.
Spare Parts Strategy and Procurement
This is where procurement managers earn their salary. A maintenance plan without a spare parts plan is a fiction. ABB supports ABB Emax 2 spares for a minimum of 10 years after end of production, but lead times for specific kits can stretch to 16 weeks, especially for harsh-environment variants and the larger E4.2/E6.2 frames.
The minimum on-site spare kit for a facility running multiple Emax 2 frames should include: one complete arc chute set per frame size, one set of main contacts per frame size, two Ekip trip units of the predominant variant, a closing coil (YC), a shunt trip coil (YO), an undervoltage release (YU) if fitted, and a motor operator. For mission-critical sites — data centres, hospitals, continuous-process plants — we recommend a hot spare: a complete drawn-out unit of the highest-population frame, racked into a designated test cubicle and kept ready for swap.
For mixed installations using ratings from 1000 A through 1600 A, stocking a representative ABB 1SDA070821R1 E1.2B 1250 as a hot spare gives flexibility because the trip unit can be reset to match the protected feeder. Detailed sizing logic is covered in how to size ABB Emax 2 for LV distribution panels.
Documentation, Compliance, and the Audit Trail
If it isn't documented, it didn't happen. Every PM visit on an ABB Emax 2 must produce a record containing: date, technician name and certification, breaker tag and serial number, operations counter reading, Ekip event log export, contact wear measurement, lubrication confirmation, trip test results with injected currents and measured times, and a clear pass/fail verdict.
For facilities under IEC 61439 switchgear assembly compliance or NFPA 70B (the US equivalent maintenance standard), this record is what an insurer or AHJ will demand after any incident. ABB's Ekip Connect software exports a structured maintenance report directly from the trip unit; combine that with a paper checklist signed by the technician and you have a defensible audit trail.
For a refresher on what the Emax 2 actually is and where it fits in ABB's portfolio, see What Is the ABB SACE Emax 2? Features, Models and Key Benefits, and for the full ratings reference used in maintenance planning, the ABB Emax 2 full technical specifications article documents every Icu, Icw, and dimensional figure.
Coordinating Emax 2 Maintenance With Downstream Devices
An ABB Emax 2 rarely sits alone. It feeds downstream miniature circuit breakers, residual current devices, and protection relays, and the maintenance schedule must respect that hierarchy. There is no point recalibrating the Emax 2's S-function setting if the downstream MCB curves haven't been verified in the same outage window. Selectivity is a system property, not a device property.
In practice, we plan PM around the highest-impact device. The Emax 2 outage drives the schedule; downstream devices are inspected during the same window because the bus is already de-energised. This is also when you'd compare maintenance burden between vendor families — a question covered in ABB Emax 2 vs Schneider MasterPact MTZ, where total cost of ownership over 20 years is dominated by PM labour, not initial price.
Related Reading
- ABB Emax 2 Nuisance Tripping: Root Causes, Diagnostic Steps and Fixes
- ABB Emax 2 FullTechnical Specifications: Current Ratings, Breaking Capacity and Dimensions
- How to Size ABB Emax 2: Step-by-Step Calculator for LV Distribution Panels
- ABB Emax 2 in Data Centers: MDB Design, Redundancy and Uptime Considerations
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Frequently Asked Questions
How often should an ABB Emax 2 be inspected if it operates fewer than 100 times per year?
Even with very few operations, the calendar interval governs. Perform an L1 visual inspection every 6 months and an L2 functional test every 12 months. Mechanical lubrication degrades and electronic components age regardless of operation count, so the time-based schedule remains in force. Stretch the L3 detailed inspection only with documented justification based on Ekip event log data.
Can I use any synthetic grease on the operating mechanism?
No. Use only the lubricants specified in ABB document 1SDH001000R0002. Generic lithium or multipurpose greases work briefly, then either gum up at low temperature or migrate onto contact surfaces. We've documented failure-to-close events on Emax 2 breakers in cold-climate substations traced directly to non-approved grease, so this is not a place to economise.
What is the expected service life of an Emax 2 before overhaul?
For an E1.2 frame, ABB publishes 12,500 mechanical and 10,000 electrical operations at Ie. Larger frames such as E4.2 and E6.2 offer higher mechanical endurance — typically 20,000 operations. In calendar terms, expect 25–30 years of service with proper PM, and an L4 overhaul somewhere between year 10 and year 15. The exact figures depend on frame size and are documented in the Emax 2 technical specifications guide.
Do I need to test the Ekip trip unit if it shows no faults on the display?
Yes. The Ekip self-test verifies internal logic and power supply, but it does not verify the rogowski coil response, the trip coil energy, or the calibration of the protection curves. A secondary injection test using an Ekip TT or equivalent is the only way to confirm the device will trip within IEC 60947-2 tolerance at the actual set points. Self-test passed is necessary, not sufficient.
If a breaker has cleared a major short-circuit, what maintenance is required immediately?
Treat any interruption above 50 % of Icu as a special event. Rack the breaker out, remove the arc chutes, inspect contact erosion against the wear indicator, measure the contact gap, check the arc chute splitter plates for damage, and download the Ekip event log to record the I²t and arcing time. If contact wear has crossed the threshold or arc chute damage is visible, replace before returning to service. Do not assume that "the breaker tripped, therefore it's fine."
Can preventive maintenance be performed without de-energising the busbar?
Only L1 visual inspection. Anything beyond visual checks — racking out, mechanism operation, contact inspection, trip testing — requires the breaker to be in the test or disconnected position, and L3 work additionally requires the busbar isolated and earthed per the site lockout-tagout procedure. Live-line maintenance on an Emax 2 is not a recognised practice and is not supported by ABB.
What's the minimum spare parts holding for a site with ten Emax 2 breakers?
One complete arc chute kit per frame size present, one main contact kit per frame size, two spare Ekip trip units matching the most common variant, one each of YC closing coil, YO shunt trip, and motor operator, plus consumables (grease, cleaning solvent, secondary disconnect contacts). For critical sites, add a hot-swap drawn-out unit of the dominant rating — for many MDB designs that's a 1250 A or 1600 A E1.2/E2.2 frame.
Conclusion
Preventive maintenance on an ABB SACE Emax 2 is not a checkbox exercise. It's the engineered counterpart to the device's published ratings, and skipping it quietly invalidates the warranty, the breaking capacity, and the protection coordination study you paid a consultant to produce. The procedure scales with severity: visual checks every six months, functional tests yearly, detailed inspections every five years, and overhaul at end of electrical life or year ten. Adjust for environment, document everything, and stock spares against lead time, not against optimism.
The breakers themselves — from the 630 A E1.2B 630 through the 2000 A E2.2B 2000 — are designed for a 25 to 30 year service life, but only when the maintenance program matches the engineering. For the complete selection-to-service methodology including sizing, application, and lifecycle planning, see the parent ABB SACE Emax 2 selection, application and maintenance guide, and for the broader theory underpinning every ACB maintenance decision, the air circuit breaker engineering guide remains the reference we hand to every new commissioning engineer on day one.
