Rice Lake Load Cells - Wiring for Hazardous Environments - Manual (Page 4)

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About This Manual
When specifying intrinsically safe (IS) applications, begin by identifying the environment as Classification I, II,
or III; Division 1 or 2; and Group A, B, C, D, E, F, or G. Plant safety engineers and licensed electricians should
provide you with hazardous environment classifications. Next, determine the location of each of the components
with respect to safe and hazardous areas. When going from hazardous to safe areas, IS barriers may be needed.
Upon confirming the classification and environment, review the relevant control drawings for each component,
remembering to check for any limiting factors. Generally, indicator control drawings take precedence over other
component control drawings. The next recommended step is to draft an installation plan. Make sure to have plant
safety engineers and licensed electricians verify and approve the plan before installation.
To help make specifying IS weighing applications easier, Rice Lake Weighing Systems offers a complete line of
Factory Mutual (FM) approved load cells, mount kits, and weighing platforms using FM-approved load cells.
Our IS indicators and full range of barrier options provide accuracy and durability in hazardous
environments.This equipment is intended only for industrial applications.
NOTE: Because of the restrictive nature of barriers, the use of sense leads between the barrier and the
indicator is always recommended.
Do not use these guidelines as your only references for scale installations. While
performing installation or maintenance, refer to the manufacturer’s manual for
procedures that are characteristic to the equipment being serviced. It is important to be
familiar with all standards, recommended practices, and codes that apply to your
installation.
Using the Drawing Package
This package provides FM-approved wiring diagrams for load cells distributed by Rice Lake Weighing Systems
and approved by Factory Mutual for explosive environments. To locate the appropriate wiring diagram in the
manual, you will need to know three things in addition to the environmental rating:
• Load cell model number (RL1140, RL70000, etc.)
• Manufacturer of the barrier (if any) used (MTL, Stahl, etc.)
• Maximum load cell excitation voltage supplied by your power source (10 VDC, 20 VDC, etc.)
This material is organized into three main sections, each comprised of a numbered control drawing with several
sheets. All FM-approved Rice Lake Weighing Systems load cells carry a label referencing one of these five
control drawings (shown below). On the Contents page, locate the section that deals with the control drawing
specified on the load cell’s label. Then look under that section heading in the Contents to find the pages dealing
with the barrier you are using. Turn to those pages and locate the correct diagram for the hazardous environment
rating and excitation voltage of your application.
FM Approved Load Cell Label
Caution
Intrinsically Safe Class I, II, III
Division 1, Groups A, B, C, D, E, F, G
Nonincendive Class I, Division 2
Groups A, B, C, D
Suitable Class II, Division 2, Groups F, G
Suitable Class III, Division 2
When Installed per RLWS Control Drawing 66090