Schneider Electric Masterpact MTZ air circuit breaker (MTZ1/MTZ2/MTZ3)
Manufacturer: Schneider Electric
Schneider Masterpact MTZ air circuit breakers to 6,300 A and 150 kA, the most liquid modern ACB on the used market
This model is part of SecondWatt’s switchgear research catalogue. Specifications and price observations are included where supported by sources. Equipment availability and commercial terms require confirmation.
Schneider Masterpact MTZ dossier: MTZ1-MTZ3 breakers to 6,300 A and 150 kA, Micrologic X, used pricing 1,740-32,930 USD, counterfeit screens, inspection.
Masterpact MTZ is Schneider Electric's flagship LV air circuit breaker: MTZ1 (630-1,600 A, Icu to 65 kA at 415 V), MTZ2 (800-4,000 A, to 100 kA with 150 kA L1 variants), and MTZ3 (4,000-6,300 A), at 400-690 V AC under IEC 60947-2 with UL 1066/ANSI C37 versions, plus DC variants. The Micrologic X trip unit samples at 6.4 kHz, captures waveforms of the last 10 trips, swaps in about 10 minutes, and needs a 24 VDC auxiliary supply for full function, the single most-missed item on used units. The MTZ Active generation launched March 2024 with a 30% circularity claim.
It is a circuit breaker rather than a switchgear lineup, and dealers list it under low-voltage breakers rather than switchgear. The used market is deep and priced: a used MTZ2-30H 3,000 A sold at 1,740 USD, a new-in-packaging MTZ2 800 A listed at 9,000 USD, a gray-channel new MTZ2 40H1 4,000 A from Dubai at 12,000 USD, and a configured MTZ2 16H3 drawout in dealer stock at 32,930 USD.
Counterfeit exposure is documented: Schneider runs a formal counterfeit program citing 189 trademark-abusing shadow companies, and the 2007 CPSC counterfeit Square D recall remains the canonical warning for this brand's used channel.
Why it matters
Masterpact is the highest-liquidity modern breaker nameplate, which makes it the pricing benchmark for the whole LV secondary market: 1,740 USD used to 32,930 USD configured spans condition, operation type, trip unit, and warranty. That price curve, the 24 VDC VPS requirement and the counterfeit screens are what a used-MTZ buyer needs before bidding.
Who buys it
Data center and industrial owners of Masterpact-equipped switchboards buy spares and replacements; contractors buy tested units against distributor queues; gray-channel export stock tempts price-driven buyers who must then verify provenance, VPS modules, and firmware. The 19x observed price spread rewards buyers who know what drives it.
Role in the data center
Main and feeder air circuit breakers in Square D and Schneider low-voltage switchboards feeding UPS input, UPS output and mechanical buses. MTZ2 and MTZ3 frames carry hyperscale mains at 3,000-6,300 A, where the Micrologic X metering doubles as the branch-circuit measurement point for the power management system.
Key specifications
| MTZ1 range | 630-1,600 A (Icu to 65 kA @415 V) |
|---|---|
| MTZ2 range | 800-4,000 A (to 100 kA; 150 kA L1) |
| MTZ3 range | 4,000-6,300 A |
| US example rating | MTZ2 16H3: 1,600 A @635 V, 100 kA |
| Standards | IEC 60947-2; UL 1066/ANSI C37 |
| Trip unit | Micrologic X, 6.4 kHz, Bluetooth/Ethernet |
| Aux power requirement | 24 VDC VPS module for full function |
| Observed used MTZ2-30H | 1,740 USD (3,000 A, sold 2026-05) |
| Observed configured 16H3 | 32,930 USD (dealer stock) |
| MTZ Active launch | March 2024 |
Technical summary
Frames: MTZ1 630-1,600 A; MTZ2 800-4,000 A; MTZ3 4,000-6,300 A. Icu: 65 kA (MTZ1) to 100-150 kA (MTZ2 by tier). Voltage: 400-690 V AC; DC variants to 1,500 V. Standards: IEC 60947-2; UL 1066 / ANSI C37 versions. Trip unit: Micrologic X, 6.4 kHz sampling, last-10-trip waveforms. Aux requirement: 24 VDC (VPS module) for full trip-unit function. Field swap: trip unit replaceable in ~10 minutes. Generation: MTZ Active launched March 2024 (30% circularity claim).
Major variations
Three frames (MTZ1, MTZ2, MTZ3) across N1, H1, H2, H3 and L1 interrupting tiers, 3-pole and 4-pole, fixed or drawout, manually or electrically operated, in IEC 60947-2 or UL 1066 builds, with Micrologic X trip units from level 2.0X to 7.0X and DC variants for battery and solar duty. The 2024 MTZ Active generation is the current build. Legacy Masterpact NW and NT units share dealer channels and search terms but not cassettes, trip units or spare parts, which is the most common mis-purchase in this family.
Configurations and options
Three frames, MTZ1 at 630-1,600 A, MTZ2 at 800-4,000 A and MTZ3 at 4,000-6,300 A, and within a frame the N1, H1, H2, H3 and L1 interrupting tiers change capability and price without changing the ampere rating. The other order variables are 3-pole or 4-pole, fixed or drawout, manual or electrical operation, IEC 60947-2 or UL 1066 build, and the Micrologic X trip-unit level from 2.0X to 7.0X. DC variants exist for battery and solar duty, and the 2024 MTZ Active generation is the current build. On used stock the trip-unit level and the presence of the VPS module are what a buyer is actually paying for.
Compatibility and dependencies
The most-missed dependency on a used MTZ is the 24 VDC auxiliary supply: full Micrologic X function requires the VPS module, and a breaker bought without it will not deliver the metering and communications it was priced for. The trip unit is field-swappable in about ten minutes, which makes trip-unit level a serviceable variable rather than a fixed property. Drawout units need their own cassette, and legacy Masterpact NW and NT share dealer channels and search terms but not cassettes, trip units or spare parts, which is the most common mis-purchase in this family. Interrupting tier has to be coordinated with the available fault current at the board, and the build standard has to match the board, since an IEC 60947-2 unit is not a substitute in a UL 1558 lineup.
Pricing and availability
Published price range: $1,740 - $32,930. Trend: rising Circuit breakers are up 47% since 2021 per Electrical Trader's index, and Masterpact tracks the curve: used MTZ2 frames now clear at 1,740-9,000 USD while configured drawout units with current Micrologic X trip units hold 30,000+ USD dealer asks. Condition, operation type, and trip-unit level, not frame size alone, set the spread. Lead time, new: Distributor stock to weeks (common frames); lineup integration 52-72 weeks. Lead time, used or refurbished: 1-4 weeks. Warranty, used: 1-year typical from reconditioning dealers.
Lifecycle and maintenance
LV power circuit breakers serve 30-40 years on 3-5 year maintenance cycles per ANSI/NETA MTS and NFPA 70B, with mechanism lubrication and injection testing the critical items. A deep reconditioning ecosystem (Relectric, NAS, Bay Power, Bullock) tests to NETA specifications and warrants units for 1 year. OEM trip-unit retrofit programs (Eaton PXR, ABB EntelliGuard R, Siemens 3WA retrofit) extend installed platforms past electronics obsolescence, which sustains used-breaker values.
Thermal and emissions profile
Switchgear produces no combustion emissions; the regulatory profile is electrical safety and materials. NFPA 70B became a standard in its 2023 edition, making maintenance programs mandatory rather than recommended, and arc-flash rules (NFPA 70E) govern work practices. LV air-insulated gear carries no F-gas exposure, and construction standards (UL 891, UL 1558, IEEE C37.20.1) plus arc-resistant options under IEEE C37.20.7 define the safety envelope buyers should verify.
Common failure points
- Mechanism springs and lubrication — Slow trips, trip-free on close, failure to latch on aged units
- Trip unit electronics — Nuisance trips or no-trip from aged or obsolete electronics
- Contacts and arc chutes — Overheating and interruption failure from eroded contacts or cracked chutes
- Secondary wiring — Control faults from damaged secondary disconnects and aux switches
- Provenance and counterfeits — Counterfeit or mis-labeled breakers fail catastrophically under fault
- Cassette and racking wear — Misalignment and cluster contact damage on worn cradles
Inspection checklist
Mechanism: exercise open/close 10+ cycles; verify the charge/close/trip sequence completes and the mechanism latches on every close; treat any failure to latch on close as a finding and check it against the OEM acceptance procedure. Trip curve: primary injection test; NETA field data shows 22% of LV power breakers off their published curves. Secondary injection: verify all 4 protection functions (LSIG) against settings; record as-found/as-left values. Contact resistance: micro-ohm test each pole; investigate readings above 1.5x sister poles. Insulation resistance: megger at 1,000 V per ANSI/NETA MTS acceptance tables. Contact wear: inspect arcing contacts and wear indicators against the OEM replacement limit. Arc chutes: remove and inspect for cracks, erosion, and metal splatter; replace damaged chutes. Lubrication: verify mechanism grease condition; dried lubricant is the leading slow-trip cause on 20+ year units. Racking: exercise draw-out mechanism through connect/test/disconnect; verify shutter operation.
Procurement channels
eBay (BoulderBreakers, mccelectricalsupply), IPS configured stock, NAS Masterpact collection, and Surplus Record's Square D LV breaker category; counterfeit screening and VPS-module verification are mandatory steps.
Regional notes
Two separate builds under one name: IEC 60947-2 units at 400-690 V AC for IEC markets, and UL 1066 and ANSI C37 versions for North America sold under the Square D brand. The build has to be read off the nameplate rather than the model designation. Counterfeit exposure is documented and jurisdiction-relevant: Schneider runs a formal counterfeit programme citing 189 trademark-abusing shadow companies, and the 2007 CPSC counterfeit Square D recall remains the standing warning for this brand's North American used channel. Gray-channel stock exported from outside North America carries no verifiable warranty position.