Can I mix outlets and lighting on one 20 amp circuit all with 12 g wire?
I have an open unfinished basement with a 20 amp circuit which supplies only a junktion box. It used to have a pull light on it. I have continued the 12 gage wire, which entered the junction box originating in the panel, from the junction box to two new floresent lights and ran further 12 gage wiring up the stairs to a single pole swtich at the basement's enterence. I had planned to put outlets tapping off the two lights and the switch. I have seen electricians tap off 20amp supplied outlets to supply over head lights (even then switching from the 12 gage wire, which supplied the outlet from a 20 amp breaker, to a 14 gage wire to supply the overhead's single pole light switch and conninue the 14g on to the light itself). I have also seen electricans tapping off 15 amp light circuits to put in an outlet and beyond that an outside GFCI circuit.
My first concern had been that the light fixtures had wiring which should not be on 20 amp circuit. But fixtures always seem to come with gages much smaller than even the 14 g wire. I referred to the lights instructions and saw no mention of circuit capacity restrictions. I referred to NEC2008 and it seems they note that 18 gage fixture wiring is permissible with 20amps. Furthermore, light circuits are permitted on 20amp service.
My next concern was mixing lighting and outlet receptacles even though I see that it is common in homes. Current would be drawn through the junction box suppling the light fixture to the outlets running devices drawing more electricity than the light does. But since these fixture wires can be on strings of lights down the line from them and together they pull more current than the first light in the string would pull on its own thereby exposing the first fixture to more current in the same way a device would, then an outlet down the line should be no problem either. Also since I have an example in my home done by a licenced electrican where by he put an outlet and an outside GFCI off a 15 amp light circuit, outlets tapped off the light circuit should not present any overload problems for the light fixtures.
I had become concerned when I read a piece on Bob Vilas web page stating that one should never mix a light circuit with a 20 amp circuit. But I think he meant to say a 14 gage supplied light circuit mixed with a 20amp and otherwise 12 gage supplied circuit. He gave a possible exeception of a bathroom GFCI and a further tap up to one over head bathroon light. I think he meant a mix of wiring was possible here (20 to the outlet and 14 to the light) as I have seen done. But I am not sure since I see that it is controversial as to whether the NEC allows for this kind of mixing of wires. But I have used all 12 gage wires and a 20 amp breaker. So can my lights and my outlets get along safely and within code?
I understand that current codes are starting to ask more ideally that a string of outlets in a basement be on a separate dedicated to them alone 20 amp circuit in new construction or magor renovations. But outside of that concern, am I missing some reason why I cannot add these outlets to this 20amp, entirely 12 gage wired, 2 light fixture run?
Thank you
Jam
