Endress+Hauser Levelflex HART FMP51 Brief Operating Instructions page 36

Electrical connection
CAUTION
L
To ensure electrical safety:
‣
Do not disconnect the protective connection (6).
‣
Disconnect the supply voltage before disconnecting the protective earth (7).
Connect protective earth to the internal ground terminal (7) before connecting the
supply voltage. If necessary, connect the potential matching line to the external ground
terminal (11).
In order to ensure electromagnetic compatibility (EMC): Do not only ground the device
via the protective earth conductor of the supply cable. Instead, the functional grounding
must also be connected to the process connection (flange or threaded connection) or to
the external ground terminal.
An easily accessible power switch must be installed in the proximity of the device. The
power switch must be marked as a disconnector for the device (IEC/EN61010).
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Levelflex FMP51, FMP52, FMP54 HART
Endress+Hauser