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CIRCUIT PROTECTION
581
Standards and approvals
Sentry switch disconnectors are designed
to fully comply with the requirements of
BS EN 60947-3.
They all feature positive contact status indication
in accordance with the 17th Edition IEE Wiring
Regulations (537.2.2.1 and 537.3.2.2).
TECHNICAL SPECIFICATION
ELECTRICAL
VOLTAGE RATING
230V/400V a.c.
OPERATING FREQUENCY
50Hz
RATED SHORT CIRCUIT CAPACITY ICN
6000A
SERVICE SHORT CIRCUIT CAPACITY ICS
6000A
When backed up by a BS 1361, 100A fuse, then
the breaking capacity of the MCB is increased to
16,000A.
Energy limiting class:
3
PHYSICAL
AMBIENT OPERATING TEMPERATURE
–5°C to +40°C
CALIBRATION TEMPERATURE
+30°C
IP RATING
Front face IP4X, screw IP2X
TERMINAL CAPACITY
35mm
2
TIGHTENING TORQUE
3Nm Max
MAX. INSTALLATION ALTITUDE
2000 metres
Sentry Technical
Miniature Circuit Breakers (MCBs)
Description
Sentry MCBs are of the thermo-magnetic, current limiting type and are available with
either Type B or Type C operating characteristics.
The operating dolly may be locked in either the ON or OFF position without
affecting the ability of the trip mechanism to operate. The contacts themselves are
manufactured from carefully chosen materials, selected specifically for their low
electrical resistance and low propensity to weld under fault conditions.
Positive contact status indication
When the green indicator is visible, then a contact gap of 4mm has been achieved.
Sentry MCBs may therefore be used as single pole isolating switches where
appropriate.
Terminals
The Sentry MCB features tunnel terminals of 35mm
2
capacity on all ratings. Each
terminal has a protective shutter to prevent cable being installed incorrectly. The
terminal screws are touch proof to IP2X, captive and feature combination heads.
Modes of operation
The mechanism of the Sentry MCB has been carefully designed and engineered using
thermal and magnetic elements to detect overcurrents due to both overload and fault
currents. The MCB will operate and interrupt the supply to prevent damage to the
installation.
The thermal component is a carefully calibrated, thermally operated bi-metal element.
Larger overloads and fault current situations are dealt with using the magnetic
tripping mode of the MCB. This acts very quickly, overriding the thermal operation.
BS EN 60898 requires the tripping to occur within 100 milliseconds and the design
of the Sentry MCB allows fault currents of up to 6000A (M6) to be safely interrupted
well within this time scale.
OFF
ON