Razer Book cranking up fan and temperature when plugged in to the wallcharger

Hy all. I need some help with the following issue. I have a Razer Book. Anytime I connect it to the wall charger the fans are cranking up and the CPU temperature is also starting to raise to 80 °C (176 °F). Doesn't matter if I just browsing the internet or working in MS Office programs or playing some LoL matches. If I disconnect the Book from the wall charger the issue that is written above stops. The fans stop and the CPU temperature goes down to 45-50 °C (113-122 °F) even if I play with LoL. So my question is whether this is a bug or a feature? Sry for my bad English. Thanks in advance.