MasterPact UR

Ultra-fast circuit breakers, to protect lines up to 5000 and 6000 A, under extremely powerful energy supply conditions.

Part of PacT Series

MasterPact UR features outstanding performance in case of short circuit in terms of detection speed, breaking capacity, and current limitation. It contributes to safety and performance wherever high short-circuit current is involved..

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The worldwide benchmark for high current circuit breakers for ultra-rapid protection

  • The MasterPact UR is a low voltage power breaker (based on the Thomson effect technology) with an ultra-rapid opening system on very high short-circuit levels. Its breaking performance makes it possible to limit the short-circuit current and the prospective energy, and consequently protect the electrical installation against the electrodynamic and thermal effects of short-circuit.

  • It is a key component in very high-power installations equipped with several sources connected in parallel, where the short-circuit current can reach very high levels and where continuity of service is a must. These power breakers provide outstanding performance in terms of speed of tripping, suitable for bus bar coupling onboard merchant vessels and off-shore platforms, and for loop networks in industry, cement plants, petrochemical industry, etc..

  • Icu=Ics=50kA & Icw(1sec)=42kAThe range comes with a wide choice of standardized accessories. Its universal design allows most accessories to be used across the entire line. MasterPact UR provides peace of mind in terms of choice, installation, and operation..

  • Specifications:-

  • Rated current: 5000 and 6000 A.

  • Breaking performances: 150 kA at 440 V – 100 kA at 690 V AC.

  • Voltage rating: 690 V AC.

  • Draw out version only.

  • 3-pole construction.

  • MasterPact UR is equipped with 2 control units:

  • An electronic MicroLogic control unit for protection against overloads, low short-circuits and insulation faults.

  • A specific control unit “UR control” module for protection against high short-circuits. This module is associated with the “UR power” module which stocks the energy for tripping by Thomson effect (T.E.C.).

  • Optimized range of field-installable auxiliaries and accessories.

  • Compliance with IEC 60947-2 standard.

  • Compliance with specifications of marine classification companies: Bureau Veritas, Lloyd’s Register of hipping, Det Norske Veritas, etc.


Built from Schneider Electric’s highly reliable standard air circuit breaker, MasterPact UR was developed to allow much higher installed power with a LV design (no MV needed). It contributes to the reliability and continuity of service wherever high short-circuit current is involved, thanks to:

Optimized safety

  • Faultless protection.

  • Strong limitation.

  • High resistance to environmental stresses.

Integrated monitoring for energy efficiency

  • Electronic MicroLogic control units, integrating current, voltage, power and energy metering enabling energy-management, earth leakage protection and other advanced protection or network analysis functions.

  • Local and remote communication with trip cause (earth leakage, overload, short-circuit) and alarms (earth leakage, overload) allowing proactive operational and energy efficiency.

  • Advanced MicroLogic control unit can assist in providing corrective, preventive and predictive maintenance and energy management to identify potential savings.

Seamless installation

  • Easier maintenance: no MV needed.

  • Standardized range of auxiliaries and accessories.


Specific applications wherever high short-circuit current is involved:

  • Busbar coupling onboard merchant vessels, off-shore platforms.

  • Loop networks in industry, cement plants, petrochemical industry, etc..