
Instruction Manual Supplement
D104229X012
3660 and 3661 Positioners
February 2017
FM Hazardous Area Approvals
™
Fisher
Hazardous Area Classifications and Special Instructions for “Safe
Use” and Installations in Hazardous Locations
Certain nameplates may carry more than one approval, and each approval may have unique installation/wiring
requirements and/or conditions of “safe use”. These special instructions for “safe use” are in addition to, and may
override, the standard installation procedures. Special instructions are listed by approval.
Note
This information supplements the nameplate markings affixed to the product and the 3660 and 3661 Positioners instruction
manual (D101402X012
Always refer to the nameplate itself to identify the appropriate certification.
3661 Positioners
), available from your Emerson Automation Solutions sales office or at www.Fisher.com.
WARNING
Failure to follow these conditions of “safe use” could result in personal injury or property damage from fire or explosion, or
area re‐classification.
Intrinsically Safe, Type n, and Non‐incendive
No special conditions for safe use.
Refer to table 1 for approval information.
Table 1. Approval Information
Certification Body Certification Obtained Entity Rating Temperature Code
FM
Intrinsically Safe
Class I Zone 0 AEx ia IIC T4/T5/T6
per drawing GE28590 (see figure 1)
Class I, II, III Division 1 GP A,B,C,D,E,F,G T4/T5/T6
per drawing GE28590 (see figure 1)
Type n
Class I Zone 2 AEx nA IIC T5
Class I Division 2, GP A,B,C,D T5
Class II, III Division 2, GP F,G T5
Vmax = 30 VDC
Imax = 150 mA
Pi = 1.25 W
Ci = 0 nF
Li = 0 mH
T4 (Tamb ≤ 82°C)
T5 (Tamb ≤ 62°C)
T6 (Tamb ≤ 47°C)
- - - T5 (Tamb ≤ 82°C)
- - - T5 (Tamb ≤ 82°C)
www.Fisher.com

3660 and 3661 Positioners
February 2017
Figure 1. FM Loop Schematic for Fisher 3661 Positioner (Drawing GE28590)
HAZARDOUS LOCATION NON-HAZARDOUS LOCATION
INTRINSIC SAFETY
CLASS I, II, III, DIV 1, GROUPS A,B,C,D,E,F,G
CLASS I ZONE 0 AEx ia IIC
NON-INCENDIVE
CLASS I, DIV 2, GROUPS A,B,C,D
Instruction Manual Supplement
D104229X012
FISHER TYPE: 3661
Vmax = 30 VDC
Imax = 150 mA
Ci = 0 nF
Li = 0 mH
Pi = 1.25 W
WARNING
FOR INTRINSICALLY SAFE APPLICATIONS: THE APPARATUS ENCLOSURE CONTAINS
ALUMINUM AND IS CONSIDERED TO CONSTITUTE A POTENTIAL RISK OF IGNTION BY
IMPACT AND FRICTION. AVOID IMPACT AND FRICTION DURING INSTALLATION AND USE TO
PREVENT RISK OF IGNTION.
NOTES:
1. THE INSTALLATION MUST BE IN ACCORDANCE WITH THE NATIONAL ELECTRIC CODE (NEC),
NFPA 70, ARTICLE 504 AND ANSI/ISA RP12.6 OR ARTICLE 505.
2. CLASS 1, DIV 2 APPLICATIONS MUST BE INSTALLED AS SPECIFIED IN NEC ARTICLE 501-4(B).
EQUIPMENT AND FIELD WIRING IS NON-INCENDIVE WHEN CONNECTED TO APPROVED
BARRIERS WITH ENTITY PARAMETERS.
3. LOOPS MUST BE CONNECTED ACCORDING TO THE BARRIER MANUFACTURE'S INSTRUCTIONS.
4. MAXIMUM SAFE AREA VOLTAGE SHOULD NOT EXCEED 250 Vrms.
5. RESISTANCE BETWEEN BARRIER GROUND AND EARTH GROUND MUST BE LESS THAN ONE OHM.
6. NORMAL OPERATING CONDITIONS 30 VDC 20 mADC.
3. FOR ENTITY INSTALLATION (I.S. AND NI):
Vmax > Voc or Vt Ci + Ccable < Ca,
Imax > Isc or It Li + Lcable < La.
Pi > Po, or Pt
GE28590‐B
FM APPROVED BARRIER
Neither Emerson, Emerson Automation Solutions, nor any of their affiliated entities assumes responsibility for the selection, use or maintenance
of any product. Responsibility for proper selection, use, and maintenance of any product remains solely with the purchaser and end user.
Fisher is a mark owned by one of the companies in the Emerson Automation Solutions business unit of Emerson Electric Co. Emerson Automation Solutions,
Emerson, and the Emerson logo are trademarks and service marks of Emerson Electric Co. All other marks are the property of their respective owners.
The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy, they are not
to be construed as warranties or guarantees, express or implied, regarding the products or services described herein or their use or applicability. All sales are
governed by our terms and conditions, which are available upon request. We reserve the right to modify or improve the designs or specifications of such
products at any time without notice.
Emerson Automation Solutions
Marshalltown, Iowa 50158 USA
Sorocaba, 18087 Brazil
Cernay, 68700 France
Dubai, United Arab Emirates
Singapore 128461 Singapore
www.Fisher.com
2
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