Kitchen heater have no individual fuse supply to fuse board. That means your electrican have to get power from lighting which inside the same lighting plate.
I think if your 電氣師父 must know and check this before take the cable out. Take care your electrician whether is a professional one.
Same case as Toilet exhaust fan. Get electricity from lighting.
Told him forget the black cable. Join two black cable together and seal it in the box.
I think exisitng switch plate is too ugly...I also replace it all.
:em02:
thank you very much. actually i asked him many times and told him many neighbours had changed. i have no idea why he said can't do it. Anyway i will ask him again tomorrow.