| Thermal Insulation | Thermal Insulation | Ambient Temp | Permissible Temp Rise | Normal Total Temp | Max Permissible Hotspot Temp |
|---|---|---|---|---|---|
| Class A | Class 60 | 40 ºC | 60 ºC | 100 ºC | 105 ºC |
| Class E | Class 75 | 40 ºC | 75 ºC | 115 ºC | 120 ºC |
| Class B | Class 130 | 40 ºC | 80 ºC | 120 ºC | 130 ºC |
| Class F | Class 155 | 40 ºC | 100 ºC | 140 ºC | 155 ºC |
| Class H | Class 180 | 40 ºC | 125 ºC | 165 ºC | 180 ºC |
| Class N | Class 200 | 40 ºC | 200 ºC | ||
| Class R | Class 220 | 40 ºC | 220 ºC | ||
| Class G | Class 225 | 40 ºC | 170 ºC | 210 ºC | 225 ºC |
| Class S | Class 240 | 40 ºC | 240 ºC | ||
| Class C | Class >240 | 40 ºC | >240 ºC |
Electrical Insulating Meterials are Nonconducting material that provides electric isolation of two objects at different voltages.
Electrical Insulating Meterials are classified into different class depending on Ambient Temperature, Permissible Temperature Rise and maximum permissible hot spot Temperature is callsed as Thermal Classification.
Current Flow through conductor/busbar causes Temperature Rise of the Assembly/Object. Tmperature Rise is Average Temperature Rise of the Object above Ambient Temperature When the Object is loaded to its Name Plate Rating. Permissible Temperature Rise is, Rise upto which Properties of Insulating material will not be detoriated.
Hotspot is high energy density spot. Hotspot is the Point of the Conductor/Object where Temperatue is higher than rest of the conductor/Object, Since that is not cooled similarly Or that spot is generating more heat as compared to other parts of the conductor/object. And due to which Temperature of the Hotspot will be much higher than other Parts of Conductor/Object, upto 15 point higher.
Max permissible Hostspot Temperatue of Insulating material is, Hotspot Temperatute upto which Properties of Insulating material will not be detoriated.