Originally Posted by stevemc
I'm a supervising electrician in Chicago and have been in business for 18 years. The neutral caries the difference between the phases. For example if the black has a load of 15 amps. and the red is 10 then the neutral is carrying 5 for that circuit. The wire you are referring to is larger than 12. I haven't seen a setup like this before though, looks like a #8.
Correct me if I'm wrong, but common sense tells me that the neutral wire should be rated for the worst case scenario (one phase loaded to maximum current, the other phase completely unloaded). The bare wire in question might be #8, but it's still visibly smaller than the red and black phase wires coming to the panel.