• PTC Thermistors are semi conductor sensors. These have typical characteristics that change their resistance instantly at a specified pre-defined response temperature
    (NRT). As soon as the surrounding temperature of PTC reaches its NRT value the body resistance of PTC Thermistor rises sharply from 200 / 250 Ohms to more than 5000 Ohms.The PTC Thermistors are embedded in the overhang location of the motor windings.The NRT value of PTC is selected according to the Insulation Class of the copper windings of motor or transformers.


Technical Specification

Selection Chart for NRT of PTC Thermistors.
NRT °C Class of Ins. Cable Colour Code
70 White – Brown
80 White – White
90 Green – Green
100 A Red – Red
110 Brown – Brown
120 E Grey – Grey
130 B Blue – Blue
140 White – Blue
150 F Black – Black
160 Blue – Red
170 H White – Green
180 C White – Red
190 Orange – Black

Minilec offers CBCT for our Earth fault relay & Earth Leakage Relay.

  • Ordering InformationPrimary & Secondary Current
    Inner DiameterOuter Diameter
    Minilec Relay Model Name
  • Wherever not specified Contact Rating : 5A @ 230 V AC (resistive)