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	Subject - Changing size of conductors Rockelec I have a exhaust fan the one of my guys ran #12 thhn to, he had a voltage drop problem and bumped the circuit up to #10 thhn but left the last 20% of the run with the #12. He claims this was ok because it was on a 20 amp breaker. I know at one time there was something in the code about not being able to change size of conductors. I have failed to be able to locate this. Anyone give me a hand?? Thanks for the help! Keith Pierre Belarge This is permitted, as long as he has followed the proper splicing procedures. Also 250.122(B) requires the equipment ground conductor to be sized accordingly for change in size of the phase conductors. I would bet (I did not do the calculations) the EGC needs to be upsized to conform to this requirement. Pierre lctrc789 Yes, think of the #10 wire as a bus and the last 20% being the conductors if this helps any. As far as upping th equipment ground, not necessary here because #12 is allowed for up to 20 amp circuits. Ryan_J Pat: See 250.122(B). The EGC needs to be increased in size to #10 for the same length that the ungrounded conductors changed size.