Cabling Recommendations; Earth Regimes - Honeywell Searchpoint Optima Plus Operating Instructions Manual

MAN0905_Issue 7_07/17

4.2 Cabling recommendations

The cable used should be appropriate for the hazardous area classification and meet local, national and
company regulations. The use of industrial grade, suitably armoured field cable is recommended.
For example, three-core copper cable, with screen (90% coverage) and suitable mechanical protection (e.g.
steel wire armour or conduit).
When using HART communications, there are some additional considerations. In particular, low
®
capacitance cable should be used. Further detailed information can be found at the HART
Foundation's website www.hartcomm.org.

4.3 Earth regimes

Any earthing regime employed must avoid earth loops.
The following information is provided to assist with proper earthing of Searchpoint Optima Plus: -
• Searchpoint Optima Plus has an earth wire (green and yellow) for connection to protective earth.
This is connected to the enclosure and isolated from the other wires. Maximum voltage between earth
and the other wires is 500 V.
• There is an earthing point on the outside of the Searchpoint Optima Plus enclosure for connection to
protective earth. Alternatively, an earth connection can be made via the mounting thread, e.g. to conduit,
a metal junction box, or a continuity plate in a plastic junction box.
• Searchpoint Optima Plus does not require an instrument earth connection.
Three options to connect to protective earth:-
1. Green / Yellow Earth wire
2. External Earth point
3. Mounting Thread
4. Electrical Installation
Circuitry
Searchpoint Optima Plus with optional HART
Searchpoint Optima Plus Enclosure
Protective Earth
26
Operating Instructions
2108M0550
Communication
®
Power, Signal and
Communications Wires
Earth Wire
(Green / Yellow)
RFI Protection
Filters
output
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