Hotend Heater going too high?

Not sure if anything is going wrong, have rapido 1.0 hotend with 104 thermistor. I was printing PLA and was going to go back to ABS, but I noticed it was crackling and smoking a lot. I checked the temperature with a camera and it was almost 300 C when it was set to 250 C and was reading as 250 C. Seems odd as it is working at 220 C correctly.