ATEX certified cable type sensors "i" protection concept



with thermocouple or RTD

Such sensors are designed for use in potentially explosive atmospheres in compliance with the 94/9/CE European Directive.

"i" protection concept - Intrinsic safety - demands that a Zener barrier or a galvanic isolator limits the energy delivered to the circuit in order to prevent any arc or spark from arising.

There are 2 levels of protection:

  • "ib": the equipment is able to resist one fault of its safety components. "ib" concept applies to zones 1 or 21 and 2 or 22.
  • "ia": the equipment is able to resist two faults of its safety components. "ia" concept is compulsory in zone 0.

Zoning lays under the end user's responsibility.More information about zone classification...

These cable-type temperature sensors are efficient and easy to implement. The active part which is generally small consists in either a thermocouple or a resistance probe. It is prolonged by a flexible cable of variable length with or without junction box.

The active part may be:

  • rigid
  • flexible, mineral insulated
  • half-flexible allowing shaping

Temperature range

•  Thermocouples: -40°C to 1700°C depending on thermocouple type. More information

•  PT100: -200°C to +500°C

Warning: The user must take all precautionary measures to ensure that the calorific transfer of the sensor does not reach the self-ignition temperature of the surrounding gas or dust.

Mechanical data

The selected materials as well as the fixing system must ensure a safe reliable use. The essential features defining the sensor performance are tightness, resistance to vibrations, corrosion, shocks, wear and tear and to any disturbing factors.


1) PT100

•  sensing element  - Class A : + 0,15 + 0,002 [t°]
                             - Class B : + 0,30 + 0,005 [t°]
                             - Reduced tolerances on request  thermocouple wire tolerances
•  sensor
                             - as per  IEC 751 standards according to type of assembly: 2, 3 or 4 wires  
                             - tolerances as per  UTE 46202 standard

2) Thermocouple

•  Thermocouple wire tolerances as oer IEC 584 standard

Response time
to reach x% of the temperature scale interval (in seconds)

Diameter: 6 mm









Tests carried out without thermowell
(*)  as per UTE C46-202 standard, on a 1 x PT100 sensor, 3 wire-assembly, temperature range: –20°C + 100°C.
(**) as per UTE C46-201, on a type K thermocouple, ungrounded hot junction, inconel 600 sheath.

Applicable standards 

•  PT100 : IEC 751 & UTE 46202
•  Thermocouple: IEC584 & UTE 46201
•  94/9/CE European Directive, Potentially explosive atmospheres
•  97/23/CE European Directive, Pressure equipment
•  Whenever requested by specific applications, other applicable standards are also complied with


Cable type temperature sensors with "i" protection concept may be used in potentially explosive atmosphere provided that the requirements of the 94/9/CE European directive as well as our EC-type examination certificate LCIE 03 ATEX 6427X are complied with. Download certificate...

   All our ATEX temperature sensors are also GOST R - NANIO CCVE N° 7454152 certified.Download certificate...


"L" length: per customer request

"L1" length:

Diameter :
1.6 to 8 mm: "ia" protection concept
0.25 to 0.50 mm: "ib" protection concept

Sensing element :
  • resistance: 100 Ohms at 0°C : 1x ou 2x
    2, 3 ou 4 wire assembly
  • simplex or duplex thermocouple 
    type : K, J, T, N, S, E, B, R, C
    ungrounded hot junction

protecting sheath / tip :
for encapsulated sensors:
•  metallic (stainless steel, brass, aluminium)
•  annular, hexagonal or square crimping on cable

sheath :

for mineral insulated sensors :
      •  standard : 304L SS, 316L SS, 310 SS, inconel 600
      •  specific: inconel 601, incolloy 800, hasteloy X, AISI 446, tantale, platinum


insulation :
•  Magnesium oxide (Mgo), standard or high purity

process connection :

•  welded fitting
•  compression fitting


marking :

Marking aims at clearly indicating the use limits of the sensor. It must be readable, durable and indestructible : usually a lable under transparent protection


Each individual ATEX certified sensor is delivered with a French-English mounting instructions datasheet which can be provided in other languages on customer request.

Compensation cable international colour codes: 





















 SC / RC








(IEC 584-3 standard)

Advice :

  • immersion length: 10 x ø
  • Ohm/4-20mA transmitters may be used with the thermocouples.