Hi, I'm wiring my kitchen recess light and wonder about the neutral wire...
Here is the display : 1 single breaker 15A, 2 wires roomex, getting to my double gang switches receptacle and then, from each switches, 3 wires roomex with a share neutral to the ceiling junction box were I split to 4, 50W recess light from one switch and, 2, 50W recess light, control by the other switch. My question is: on a single phase breaker line, what will be the max load tolarated by my neutral wire... if I understand well the limit will only be the amount of my 200W divided by 120V, wich is 1.6A on 1 circuit + the amount of my other circuit, wich is 100W, divided by 120V, wich will be only .8A, on the other circuit, wich will equal to 2.4A, running back in my neutral.
14 gauge wire can run up to a load 15A, the safest should be 12A.

Did I get the thing right, can someone enlighted me on this issue.

Thanks, Frank

The neutral has to be sized the same as the line wire. Usually it's 14 gauge for a 15 amp circuit, or 12 gauge for a 20 amp circuit.

The ground wire is another question.

1 single breaker 15A, (Are you using two tandem breakers with one neutral? Or are you using a single breaker?)

2 wires roomex (are you connecting two 14 AWG Hot conductors to one breaker [e.g. Black & Red])?

Getting to my double gang switches receptacle ( What type of switches are you using simple snap switches, three way or four way [Neutral (White) never connects to a switch. If white is connected to a switch it should have a black marking on it to signify that it is an ungrounded conductor, Normally you can bring power to the switch with a black, Neutral (White would by pass the switch and go directly to the first fixture. Another Black (switched) would also go to the first fixture.)

And then, from each switch, 3 wires romex with a share neutral to the ceiling junction box were I split to 4, 50W recess light from one switch and, 2, 50W recess light, control by the other switch. (As written this does not make sense to me)

My question is: on a single phase breaker line, what will be the max load tolarated by my neutral wire... if I understand well the limit will only be the amount of my 200W divided by 120V, wich is 1.6A on 1 circuit + the amount of my other circuit, wich is 100W, divided by 120V, wich will be only .8A, on the other circuit, wich will equal to 2.4A, running back in my neutral. (?) The maximum load allowed on a 15 amp line is 15 Amps. One advantage to using a shared Neutral is that you cancel out some of the current flow back to the Neutral connection.

14 gauge wire can run up to a load 15A (Correct), the safest should be 12A. (Why would you derate the switched lines?)

Hi Don, thanks for looking at my request.
First, I'm using a single pole 15A breaker. My roomex is a 14 gauge coming from my breaker to my switches box (I have to single switch 2 way) Then from the box, I run a 3 wires cable to my ceiling junction box were I have connected 1 circuit of X4 50W recess light (red wire) and then (the black wire) is connecting my other X2 50W recess light circuit. My concern was about the share neutral, I mean the split neutral in my ceiling jonction box.
I believed as long as I don't go over a maximum amperage, witch is 15A, running back in my neutral, everything is correct?

Franck

Franck,

Okay, let's see if we can define this circuit a little cleaner for yo.

1) Do you need the fixtures to be on different switches?

2) Do you understand that a shared neutral is defined as a circuit originating at the electrical panel. In your case it would consist of two 15 amp breakers, a 14/3 with ground cable with black on breaker 1, red on breaker 2, White on the Neutral bus bar and equipment ground attached to ground bus bar.

3) On the other end of the cable, Switch 1 (lower terminal screw) Black from breaker 1. Switch 2 (lower terminal screw) Red from Breaker 2. White is not connected to any of the switches it goes directly to the fixtures.

4) From Switch 1 (top screw) Black to Fixture 1, White to Fixture 1. Then connect Black and White to each succeeding fixture via pig tails.

5) From Switch 2 (top Screw) Red to fixture 2 set, White to fixture set 2.

Personally if you are only talking about six 50 Watt lights, you are only using 300 watts on a circuit that is capable of supporting 1800 watts.

I would not waste the breaker space. I would use I breaker and then split into two circuits. However, that is not a shared neutral, as defined in the NEC.

Remember to connect the equipment grounding conductor to all fixtures and switches.

Thanks Don,
I was just uncertain about the neutral, but your explanation make it clear.
I will have other question later on, for now, thanks a lot for your help!
Franck - Montreal

A 15 amp circuit will handle 1800 watts, since they could be on more than 3 hours, Max is 80%, or 1800 watts X .8 = 1440 watts.
That neutral is not a shared neutral, like in a Multi circuit.
Just make sure any recepticles, lights, or any loads neutrals are the neutral for that circuit.
Don't use that neutral with anothers circuits hot.