Schneider Electric Masterpact MTZ air circuit breaker (MTZ1/MTZ2/MTZ3)

Schneider Masterpact MTZ air circuit breakers to 6,300 A and 150 kA, the most liquid modern ACB on the used market

Schneider Electric Masterpact MTZ air circuit breaker (MTZ1/MTZ2/MTZ3) is one of 41 data center switchgear tracked in the SecondWatt catalogue, each with specifications, lead times and indicative secondary-market pricing.

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 also a breaker, not a switchgear line, and the backlog category should say so. 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. Publishing that curve, with the 24 VDC VPS gotcha and counterfeit screens, is exactly the buyer intelligence nobody else offers.

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 ACBs in Square D/Schneider LV switchboards feeding UPS and mechanical buses; MTZ2/MTZ3 frames carry hyperscale mains.

Key specifications

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)

Pricing and availability

Published price range: $1,740 – $32,930. Trend: up 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.

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 charge/close/trip sequence without trip-free behavior 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 Auxiliary wiring — verify secondary disconnects, charging motor voltage (24-125 V options), and aux contacts Trip unit vintage — identify electronics generation; obsolete trip units reprice the breaker toward core value Counterfeit screen — verify serial numbers with the OEM; counterfeit LV breakers documented since the 2007 CPSC recall Ratings match — confirm frame, sensor/rating plug, and interrupting rating (kA at 480 V) against the application Listing match — verify cassette/cradle compatibility and UL 1066 or UL 489 listing matches the switchgear type Records — factory test report, service history, and injection results; missing records reprice toward as-is

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.