10. What is the conductor ampacity required for a 20 kW, 240 volt central space heater? 11. What is the ampacity of three No. 4 THWN conductors installed in an ambient temperature of 30 degree Celsius? 12. What is the ampacity of three No. 3/0 conductors installed in free-air? 13. What is the ampacity of eight 4/0 THHN conductors installed a raceway in an ambient temperature of 100 degreee F? 14. What is the ampacity of ten No. 6 THWN conductors installed in a raceway in an ambient temperature of 40 degree C? 15. What is the ampacity of a No. 12 THW when in a conduit with 5 other No. 12 THW's and two bare No. 12 grounding conductors? (all are copper conductors) i need to know how to set up the problem and where to get the info in the nec code book please