Manual
    <2.  Handling Cautions>
2-1
IM 01C25T04-01EN
2.  Handling Cautions
2.1  Installation of an Explosion-
Protected Instrument
If a customer makes a repair or modication to 
an intrinsically safe or explosionproof instrument 
and the instrument is not restored to its original 
condition, its intrinsically safe or explosionproof 
construction may be compromised and the 
instrument may be hazardous to operate. Please 
contact Yokogawa before making any repair or 
modication to an instrument.
CAUTION
This instrument has been tested and certied 
as being intrinsically safe or explosionproof. 
Please note that severe restrictions apply to this 
instrument’s construction, installation, external 
wiring, maintenance and repair. A failure to abide 
by these restrictions could make the instrument a 
hazard to operate.
WARNING
Maintaining the safety of explosionproof 
equipment requires great care during mounting, 
wiring, and piping. Safety requirements also 
place restrictions on maintenance and repair. 
Please read the following sections very carefully.
WARNING
The range setting switch must not be used in a 
hazardous area.
IMPORTANT
All the blind plugs which accompany the 
transmitters upon shipment from the factory are 
certied by the applicable agency in combination 
with the transmitters. The plugs which are 
marked with the symbols “◊ Ex” on their surfaces 
are certied only in combination with the 
transmitters.
2.1.1  FM approval
a.  FM Explosionproof Type
Caution for FM Explosionproof type
Note 1. The transmitters with optional code /FF1 
are applicable for use in hazardous 
locations:
•  Applicable Standard:  
FM3600, FM3615, FM3810,  
ANSI/NEMA 250 
•  Explosionproof for Class I, Division 1, 
Groups B, C and D.
•  Dust-ignitionproof for Class II/III, Division 1, 
Groups E, F and G.
•  Enclosure rating: NEMA 4X.
•  Temperature Class: T6
•  Ambient Temperature: –40 to 60°C
•  Supply Voltage: 32V dc max.
•  Current Draw: 15 mA dc
Note 2. Wiring
•  All wiring shall comply with National Electrical 
Code ANSI/NFPA70 and Local Electrical 
Codes.
•  When installed in Division 1, “FACTORY 
SEALED, CONDUIT SEAL NOT 
REQUIRED.”
Note 3. Operation
•  Keep the “WARNING” nameplate attached to 
the transmitter.
  WARNING: OPEN CIRCUIT BEFORE 
REMOVING COVER. 
FACTORY SEALED, CONDUIT SEAL NOT 
REQUIRED. 
INSTALL IN ACCORDANCE WITH THE 
USERS MANUAL IM 01C25.
•  Take care not to generate mechanical 
sparking when accessing the instrument and 
peripheral devices in a hazardous location.
Note 4. Maintenance and Repair
•  The instrument modication or parts 
replacement by other than authorized 
representative of Yokogawa Electric 
Corporation is prohibited and will void 
Factory Mutual Explosionproof Approval.










