EXHeat HEF 100, Installation, Operation, & Maintenance Instruction, Page: 9 / 27

6. Installation Instructions
Page 9
Electrical Supply Connection
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Refer to wiring diagrams in Section 13 .
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There are no cable entries on the HEF Anti-Condensation heater. Connection is
to be made via the manufacturer installed 3 core supply cable.
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Connections to this heater are to be made via the 3-core flex. The flex is to be
installed into suitable rated terminals/joint box, crimped and terminated correctly.
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Refer to Section 7.
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Before connection ensure that the supply corresponds with that specified on the
nameplate label, and that the sizes and types of cables to be used are suitably rated
for the load and temperature of the product.
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Each heater circuit must be protected by a suitably rated over current device and
earth leakage circuit breaker device. See below for earth connection details.
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The HEF heater is not designed to be taken apart and inspected as all of the internal
connections are sealed.
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CAUTION – Check nameplate for correct voltage and classification.
Earth Connection
WARNING – These heaters MUST BE EARTHED.
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The internal earth connection on the HEF range is obtained by the connection of the
3-core supply cable. The external earth connection is to be made via one of the
heaters fixing methods. No additional earth connections are required.
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Should a thermostat be used, please refer to the thermostats IOM for earth
connection points.
Earth-fault Protection
For safety reasons, it is essential to limit the magnitude and duration of earth-fault currents.
It is impractical to cover all possible systems, however note that, regardless of which system
is used, the heater must be protected by a suitable device wired to shut down the heater in
the event that a heater element fails to earth. Suitable devices include a residual current
device (RCD) – this is the preferred method and should be used whenever possible – or an
insulation monitoring device.
•
Maximum recommended setting for the RCD: 300mA/10mS. The duration time of
10mS (ten milliseconds) ensures that any fault is detected within a single cycle of a
thyristor system (where applicable).
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Maximum recommended setting for the insulation monitoring device: Insulation
resistance is not greater than 50 ohms per volt of rated voltage.
Ensure that the equipment is earthed in accordance with the plant earthing philosophy.