Honeywell Searchpoint Optima Plus - 4.2 Cabling recommendations; 4.3 Earth regimes

MAN0905_Issue 7_07/17 Searchpoint Optima Plus with optional HART
®
output
Operating Instructions
2108M0550
26
4.2 Cabling recommendations
Thecableusedshouldbeappropriateforthehazardousareaclassicationandmeetlocal,nationaland
companyregulations.Theuseofindustrialgrade,suitablyarmouredeld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
®
Communication
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.
4. Electrical Installation
Circuitry Searchpoint Optima Plus Enclosure
Power, Signal and
Communications Wires
Earth Wire
(Green / Yellow)
RFI Protection
Filters
Protective Earth
Three options to connect to protective earth:-
1. Green / Yellow Earth wire
2. External Earth point
3. Mounting Thread