Notes For Intrinsically Safe Installation - GE Masoneilan 12420 Instruction Manual & Safety Manual

2.2.7. N
OTES FOR INTRINSICALLY SAFE INSTALLATION
Note 1: HAZARDOUS LOCATION
Refer to the device label for the description of the environment in which the device may be installed.
For Div 1 areas the barriers are always required. For Div 2 areas the barriers are not required as long as Div 2 wiring practices
comply with the local electrical code and the supply voltages are normally less than 30 Volts.
Note 2: FIELD WIRING
Intrinsically Safe wiring must be made with grounded shielded cable or installed in grounded metal conduit. The electrical
circuit in the hazardous area must be capable of withstanding an A.C. test voltage of 500 Volts R.M.S. to earth or frame of the
apparatus for one minute. Installation must be in accordance with GE's guidelines. The installation including the barrier
earthing requirements must comply with the installation requirements of the country of use.
Factory Mutual requirements (USA): ANSI/ISA RP12.6 (Installation of Intrinsically Safe Systems for Hazardous (Classified)
Locations) and the National Electrical Code, ANSI/NFPA 70. Division 2 installations must be installed per the National Electrical
Code, ANSI/NFPA 70. See also, note 4.
CSA requirements (Canada): Canadian Electrical Code Part 1. Division 2 installations must be installed per the Canadian
Electrical Code Division 2 Wiring Methods. See also note 4.
Note 3: PRIMARY OUT (+) and (-) 4-20 mA Terminals
These terminals are the main loop power of the 12400 and provide a 4 to 20mA signal related to the level measurement or the
embedded controller output for level control process. A transmitter type barrier with 250 Ohm series resistance (internal or
external) is used for this connection; for example, MTL 788 or 788R. For controller application, an active barrier with 4-20mA
retransmit can be used to drive a valve positioner.
Entity Parameters: Vmax= 30 VDC; Imax=125 mA; Ci=2 nF; Li=500 μH; Pmax=900 mW
Note 4: SECONDARY OUT (+) and (-) 4-20 mA Terminals
These terminals provide an additional 4 to 20 mA signal related to the level measurement. Use a transmitter type barrier with
250 Ohm series resistance (internal or external) for this connection; for example, MTL 788 or 788R.
Entity Parameters: Vmax=30 VDC; Imax=125 mA; Ci = 9 nF; Li=500 μH; Pmax=900 mW.
NOTE: The secondary out must not be connected in an Intrinsic Safe installation which requires FM or CSA approval.
Note 5: SW1 & 2 (+) and (-) Terminals
There are two independent isolated solid state switch contact outputs on the 12400. They are labelled SW#1 and SW#2. The
switches are polarity sensitive – that is, conventional current flows into the plus terminal. Examples of suitable barriers are MTL
707, MTL 787 and MTL 787S.
Entity parameters are: Vmax=30 VDC; Imax=125 mA; Ci = 4.5 nF; Li=10 μH; Pmax=900 mW.
Note 6: Controller mode
The barrier is a Controller Output Type; for example, MTL 728. This barrier can be driven by an active barrier with 4-20mA
retransmit or by the control system.
Entity Parameters: The optional device may be an I/P type 8000 series or a valve positioner type SVI II AP.
Note 7: Entity Requirement
Cable capacitance and inductance plus the I.S. apparatus unprotected capacitance (Ci) and inductance (Li) must not exceed
the allowed capacitance (Ca) and inductance (La) indicated on the associated apparatus. If the optional HART handheld
®
Communicator (type DPI 620) is used on the Hazardous Area side of the barrier, then the capacity and inductance of the
communicator must be added and the communicator must be agency approved for use in the hazardous area. Also, the
current output of the Hand Held Communicator must be included in the current output of the associated equipment.
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