Masterpact MTZ2/MTZ3 Operating Conditions

Masterpact MTZ devices are designed and tested for operation in industrial atmospheres. It is recommended that equipment be cooled or heated to the proper operating temperature and kept free of excessive vibration and dust.

Masterpact MTZ—Ambient Temperature

Masterpact MTZ devices can operate under the following temperature conditions:

  • Electrical and mechanical characteristics specified for an ambient temperature of -25°C to +70°C (-13°F to +158°F).

  • Circuit breaker closing specified down to -35°C (-31°F) by manual operation with closing pushbutton.

Storage conditions are as follows:

  • -40°C to +85°C (-40°F to +185°F) for the device without the control unit.

  • -25°C to +85°C (-13°F to +185°F) for the control unit.

Masterpact MTZ—Extreme Atmospheric Condition

Masterpact MTZ devices have successfully passed tests for extreme atmospheric conditions, defined by the following standards:



IEC 60068-2-1

Dry cold, at -40°C (-40°F)

IEC 60068-2-2

Dry heat, at +85°C (+185°F)

IEC 60068-2-30

Damp heat (temperature +55°C (+131°F), relative humidity 95%)

IEC 60068-2-52 level 2

Salt mist

Masterpact MTZ—Industrial Environments

Masterpact MTZ devices can operate in the industrial environments defined by IEC 60947 (pollution degree up to 3).

Check that devices are installed in suitably cooled switchboards without excessive dust.



Corrosive industrial atmospheres

Category 3C3 compliant with IEC 60721-3-3

Sea salts 0.8 to 8 mg/m² day average over the year

Compliant with IEC 60721-2-5

Mechanically active substances

Category 3S3 compliant with IEC 60721-3-3

Beyond these conditions, Masterpact MTZ devices must be installed inside switchboards with an IP rating equal to or greater than IP54.

Masterpact MTZ—Vibration

Masterpact MTZ devices have successfully passed tests for the following vibration levels, in compliance with IEC 60068-2-6 and IEC 60068-2-27:

  • 2 Hz to 13.2 Hz: amplitude +/- 1 mm.

  • 13.2 Hz to 100 Hz: constant acceleration of 0.7 g.

Masterpact MTZ—Altitude

Masterpact MTZ devices are designed and tested to operate at altitudes below 2,000 m (6562 ft.).

At altitudes above 2,000 m (6562 ft.), the characteristics of the ambient air (electrical resistance, cooling capacity) lower product characteristics as follows:



2,000 m
(6,562 ft.)

3,000 m
(9,843 ft.)

4,000 m
(13,123 ft.)

5,000 m
(16,505 ft.)

Impulse withstand voltage (kV)





Rated insulation voltage (V)





Maximum rated operational voltage 50/60 Hz (V)





Rated current (A) at 40°C (104°F)

1 x In

0.99 x In

0.96 x In

0.94 x In

NOTE: Intermediate values can be obtained by interpolation.

Masterpact MTZ—Electromagnetic Disturbances

Masterpact MTZ devices have protection against:

  • Overvoltages caused by devices that generate electromagnetic disturbance.

  • Overvoltages caused by atmospheric disturbance or by a distribution-system outage (for example, a lighting system outage).

  • Devices emitting radio waves (for example, radio transmitters, walkie-talkies, or radar).

  • Electrostatic discharge produced by users.

Masterpact MTZ devices have successfully passed the electromagnetic-compatibility tests (EMC) defined by IEC 60947-2, appendix F.

The devices have passed the above tests and therefore:

  • Nuisance tripping from electromagnetic interference does not occur.

  • Tripping times are respected.

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