Terminal boxes and switches in intrinsically safe circuits can be assumed to have a temperature rise of less than 40 K and can thus have a temperature classification of

• T6 at ambient temperature not exceeding 40 °C,
• T5 at an ambient temperature not exceeding 55 °C or
• T4 at an ambient temperature not exceeding 80 °C.

So ambient conditions have their influence on safe operation even if intrinsically safe.

Keep up good work!

Arpad

veress@exprofessional.com

exprofessional.com