To the point where you would not want to hold your hand on it for an extended period of time. I actually found this after googling exactly that issue. How To Make A Nearly Invincible Iphone 5 6 Ipad Lightning Charger Cable Lightning Charger Iphone Cable If the issue disappears check the cable and its adaptor. Iphone charger very hot . Typical threshold for hot pain is 42 C. You should still be able to handle the charger comfortably and it should never cause damage to nearby surfaces. If voltage is the speed water flows through the hose then amperage is the width of the hose or how much water can flow through at once. Simultaneously press and hold either volume button and side button until slide to power off appears on the display. Your iPhone gets hot because its CPU is r. Also if I smell the USB ports on the charger when its hot I can smell. If its your iPhone that gets hot it. IPhones can only charge at 5 volts but the amperage varies from charger to charger usu...