Type KAF-K & KBF-K: Explosion proof bulb and capillary thermostats for incorporation(Under development)


Explosion proof bulb and capillary thermostats for incorporation

Wires electrical connection (component approval)

Automatic reset high limit (not fail safe), front mounting

                                                              *Under development, will be put into the market soon*

General rules for installation:

Important note: This thermostat is considered as a component by the standards of equipment for potentially explosive atmospheres.

Its incorporation into a product mandatory requests the approval of the entire device by a professional competent certified body.

These models with front mounting allow incorporation inside most existing “Ex e” junction boxes in aluminum or polyester and inside a fitting height of 60 mm.

These thermostats are intended to monitor or control temperatures in hazardous areas.

They can be used in zones 1 or 2 with gas, smoke and fog, class IIC, surface temperature T6, and for ambient temperature on housing of -50 to +80°C.

This thermostat uses a flameproof micro-switch type II2Gb, Ex dIIC .

The thermostat must be installed in an increased safety enclosure, type Ex-“e”, and electrical connections at the end of the wires must be made inside this EX-“e” enclosure.

The thermostat capillary exit must be performed by a cable gland with gasket adapted to the diameter of the capillary and providing the level of protection required by the standard.

Approvals: These thermostats are ATEX and IECEx certified.

ATEX: INERIS13ATEX9026 –U;  IECEx: INE13.0100U


Housing: aluminum, 82,2 x 37 x 57,5mm

Bulb and capillary: Copper for temperature ranges up to 50°C, stainless steel over 50°C. Capillary length 1500 mm or 3000 mm. Capillary minimum bending radius 5mm.

Temperature sensing element: oil filled bulb and capillary.

Electrical connection: H05S-K wires, 1.5 mm², standard length 500mm.  Wire ends with crimped terminals. Other lengths on request.

Ground terminals: Two M4 grounding terminals with saddle are located on the side.

Adjustment:  fixed setting, non-adjustable, factory sealed. Calibration made in liquid bath with thermostat body at 20°C +/-3°C, 100 mm capillary and bulb immersed. Temperature rise speed less than 0.5°C/min. The tripping temperature may be shifted slightly depending on the location and the ambient temperature on the housing and on the capillary. These parameters vary upon models. Consult our technical department for more information.

Mounting: Front bracket with 2 x M4 threads, 28 mm distance

Contacts: SPDT (snap action contact)

Electrical rating: Suitable for power control, remote control of relay coils or PLCs circuits.


Max rating (A) Switch Electrical life (cycles)
400VAC (KA type only) 10



15 500000
125VAC 15



15 500000
15-30VDC 2



These devices use silver contacts or silver alloy contacts. Due to the possible oxidation of the contacts in time, we do not recommend the use of AC or DC low-voltage circuits (24V or less) if the switched intensity is less than 100mA, or the switched power less than 800mW. Contact us for those applications that require gold-plated contacts. The electrical ratings given are normalized resistive circuit values.

Mechanical life: > 500.000 cycles




2D&3D Drawing

Main references with 500mm wires length (L1) 

References with standard differential References with reduced differential Calibration temperature


Capillary length

(C, mm)

Bulb diameter

(D2, mm)

Bulb length

(L2, mm)

KA, standard



KB, reduced



Max temperature on bulb (°C)
KAF——225K KBF——225K -25~ +25** 1500 6.4 152 3+/-2 2+/-1 50
KAF——205K KBF——205K 0 ~+50** 1500 6.4 152 3+/-2 2+/-1 60
KAF——525K KBF——525K 0~+70 1500 4.8 120 5+/-3 3+/-2 160
KAF——125K KBF——125K 0~+70 3000 4.8 120 5+/-3 3+/-2 160
KAF——505K KBF——505K +20~+90 1500 4.8 120 5+/-3 3+/-2 160
KAF——105K KBF——105K +20~+90 3000 4.8 120 5+/-3 3+/-2 160
KAF——505K KBF——505K +10~+150 1500 4.8 120 5+/-3 3+/-2 160
KAF——105K KBF——105K +10~+150 3000 4.8 120 5+/-3 3+/-2 160
KAF——015K KBF——015K +50~+300 1500 4 100 10+/-4 6+/-4 320