Grounding And Lightning Protection; Explosion-Proof Conduit Seal - Honeywell STT750 SmartLine User Manual

3.5.4. Grounding and Lightning Protection

Connect a wire from the Earth Ground Clamp or to the Internal Ground Connection (see
Earth Ground to make the protection effective. Use a size 8 AWG or (8.37mm
covered wire for this connection.
For ungrounded Thermocouple, mV, RTD or ohm inputs connect the input wiring shield(s) to the
Internal Ground Connection shown in
For grounded Thermocouple inputs, connect the Internal Ground Connection shown in
the same earth ground as used by the thermocouple.
As noted above, the Loop Power wiring shield should only be connected to earth ground at the power
supply end.

3.5.5. Explosion-Proof Conduit Seal

When installed as explosion proof in a Division 1 / Zone 1, Ex d Hazardous Location,
keep covers tight while the Transmitter is energized. Disconnect power to the Transmitter in
the non-hazardous area prior to removing end caps for service.
When installed as non-incendive equipment in a Division 2 hazardous location, disconnect
power to the Transmitter in the non-hazardous area, or determine that the location is non-
hazardous before disconnecting or connecting the Transmitter wires.
Transmitters installed as explosion proof in Class I, Division 1, Group A Hazardous (classified)
locations in accordance with ANSI/NFPA 70, the US National Electrical Code, Canadian Electric
Code CCSAC22.1, with 1/2 inch conduit do not require an explosion-proof seal for installation. If
3/4 inch conduit is used, a LISTED explosion proof seal to be installed in the conduit, within 18
inches (457.2 mm) of the transmitter.
Crouse-Hinds type EYS/EYD or EYSX/EYDX are examples of LISTED explosion proof seals that
meet this requirement. Transmitters installed as explosion proof in Class I, Division 1, Group A, B, C
or D hazardous (classified) locations do not require that explosion proof seal be installed in the
conduit.
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STT750 Temperature Transmitter User's Manual
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