Parameter Specification
Device Type Rotary Load Break Switch / Disconnector
Product Series MJ / MJS Series
Rated Operational Current (Ie) 60 A (at specified utilization category)
Number of Poles 2 Poles (2P)
Rated Insulation Voltage (Ui) 690 V
Rated Operational Voltage (Ue) 400 V AC / 500 V AC
Utilization Category AC-22A (Switching of mixed resistive and inductive loads).
AC-23A (Switching of motor loads or other highly inductive loads).
Rated Making & Breaking Capacity Typically ≥ 10 x Ie (e.g., 600 A) for AC-23A at 400V.
Short-Time Withstand Current (Icw) Typically 10 kA for 1 second (This is a key safety parameter, ensuring it can withstand fault currents without damage).
Mechanical Durability ≥ 10,000 operations
Electrical Durability ≥ 5,000 operations (at rated current)
Control Method Manual rotary operation via a detachable handle. The handle can be padlocked in the OFF position (typically with up to 3 padlocks).
Mounting Mounts directly onto a panel or enclosure door via a mounting kit. The switch body is mounted behind the panel.
Terminal Type Screw clamp terminals. The "B" variant may include snap-on protective terminal covers.
Terminal Connection Capacity Typically up to 35 mm² (for 60A model).
Protection Degree Switch body: IP00 (must be installed inside an enclosure).
With handle mounted on door: Typically achieves IP54 or higher for the front.
Ambient Temperature (Operation) -25°C to +60°C
Standards Compliance IEC/EN 60947-1, IEC/EN 60947-3
The ABB MJS12-60B is a rotary load break switch / isolator switch from the versatile MJ/MJS series of manual control and switching devices. It serves as a robust and reliable main switch or functional isolator in electrical distribution boards, machine control panels, and industrial enclosures.