background image

UNPACKING
Remove the Packing List and verify that you have received all equipment.  If
you have any questions about the shipment, please call the OMEGA
Customer Service Department at 1-800-622-2378 or (203) 359-1660.  When
you receive the shipment, inspect the container and equipment for any signs
of damage.  Note any evidence of rough handling in transit.  Immediately
report any damage to the shipping agent.
NOTE
The carrier will not honor any claims unless all shipping material is saved for
their examination.  After examining and removing contents, save packaging
material and carton in the event reshipment is necessary.

Fig. 2.  Connection Diagram:  Model SBG41705

Hazardous Location

Note:  For 120V application, only one fuse is
required in the  ungrounded circuit of the input line.

Fig. 1.  Connection Diagram

(All Models Except SBG41705)

Note:  All intrinsically safe wiring must be segregated
           from non-intrinsically safe wiring.

Fig. 3.  Multiple units grouped on a common,
            earth-grounded mounting plate.

Important:  Read carefully and completely before
installing or connecting the solid-state relays.

• 

Whenever possible, the actual measured parameters should be

   used in making the determination of allowable length.

 Shielded cable is not required, but if used in the application, the

   shield must be returned to ground, the same point at mounting
  tab.

GROUP

A & B

C

D

CAPACITANCE

0.1 µF

0.2 µF

0.3 µF

INDUCTANCE

3 mH

10mH

20mH

Example:  Typical values of capacitance for a twisted
pair of copper wires is between 20 and 60 pF per foot.
Using the maximum value of 60pF/ft, Groups A & B
could have a run of 1500+ feet with safety.  Inductance
of a typical twisted pair is between 0.10 and 0.20 µH/
ft, thus making a cable run in this example essentially
determined by the capacitance.

The OMEGA

® 

 SBG22445, SBG25872, SBG25873 and SBG41705 Solid-

State Relays are used as "intrinsically safe switching circuits in hazardous
locations, with non-voltage- producing sensors.  When installed in accor-
dance with this manual, these field sensors are suitable for Class I, Division
1, 2, Groups A, B, C and D, and Class II, Division 2, Groups E, F and G as
defined by Article 500 of the National Electric Code.

DESCRIPTION

SBG22445, SBG25872, SBG25873 (Non-Latching),
SBG41705 (Latching) Solid-State Relays
for Intrinsic Safety Use
Instruction Sheet M1773/0794

*(Lockwashers to be internal or external tooth type)

Fig. 4.  Unit Mounting Detail

ASSOCIATED EQUIPMENT
Caution:
  The intrinsically safe relays can be installed in panel assem-
blies in Class I, Div.2, Groups A, B, C and D or in a non-hazardous
location.  Only the sensor's terminals provide an intrinsically safe switch
circuit (Fig. 1, 2).  (Exia) means associated equipment "Appareilage
connexe", located in safe area.
MOUNTING AND ENCLOSURE CONSIDERATION

• 

Field wiring of intrinsically safe circuits is to be segregated from

   non-intrinsically safe wiring by use of suitable barriers, separate
   wireways or trays (see Fig. 3).

 Intrinsically safe and non-intrinsically safe connection points should

   be located sufficiently apart to prevent any possibility of bypassing
   or miswiring during installation or servicing of equipment.

 The enclosure shall contain a cautionary statement as follows:

   "CAUTION:  ANY SUBSTITUTION OF COMPONENTS MAY
   IMPAIR INTRINSIC SAFETY".

 The mounting plate must be grounded to ensure intrinsic safety.

   Resistance between the plate and earth ground should be less than
   one ohm.  (See Figs. 4 and 5 for recommended selection of
   grounding hardware and refer to Article 250 of the National
   Electrical Code for methods and practice.)
INSTALLATION OF SENSOR SWITCH AND ASSOCIATED
FIELD WIRING

 The nature of the sensor switch must be that it is a non-voltage-

    producing, essentially resistive termination or other device
    specifically examined and approved for use with the intrinsically
   safe solid-state relay.

 The conductors of the intrinsically safe circuit should be sealed in a

    rigid metal conduit at the point where the wiring enters the hazardous
   area.  The wiring and sensor switch should be such that conductive
   dusts in the hazardous area will not close the circuit.

 Hazardous area field wiring will store energy due to distributed

   capacitance and inductance in proportion to its length.  It is
   therefore recommended that the characteristics of the cable be
   known and judged against the length of
   run and atmosphere of exposure.  The
   following chart is presented as a guideline
  in determining the limits of reactance for
  signal loops in the hazardous area wiring
  for the intrinsically safe solid-state relays.

WARNING

Product must be maintained
and installed in strict accor-
dance with the National Elec-
trical Code.  Failure to observe
this warning could result in
serious injuries or damages.

Input

VAC

(EXIA)

Load

Fuse F1

Fuse

F1

Non-Hazardous
Location

Hazardous Location

Sensor Switch

Sensor Switch

LOAD

VAC

AC

Load

Latching Solid-State

Relay  SBG41705

On

C

Off

Non-Hazardous
Location

Earth

Ground

(2 Places)

Common

Earth-

Grounded

Mounting

Plate

Intrinsically

Safe Wiring
To Sensors

Non-Intrinsically

Safe Wiring

Multiple

Units

Resistance to ground must be from bracket to
earthing member to insure integrity of system.
(Must be below one ohm.)

Mounting

Plate

#10
Nut

Intrinsically Safe

Solid-State Relays

#10 Screw

#10 Lockwasher*

#10 Lockwasher*

Reviews: