Judging by the 'keyhole' mounting hole there, the panel was installed upside down. Neat work though. Are (or were) yellow phase conductors usual for some reason in the area, or is it a case of 'what the guy had on the van'.
I'd have been a little worried about 'yellowing' of the white wires causing phase and neutral to appear similar.
Re: Residential Service ca. 1960#152611 11/05/0502:48 PM11/05/0502:48 PM
According to the NEC, it is perfectly acceptable to use whatever color you have on the truck for an ungrounded conductor, as long as it is not white, gray, or green. There is an additional restriction on orange, which must be and may only be used on the 208V-to-ground leg of a four-wire delta, if such a system exists on the premises.
Many jurisdictions, including my own, are more restrictive.
Yes, there is double-lugging going on in here. That might have been legal at the time.
For the ungrounded branch circuit conductors, I see three colors: yellow, orange, purple, and another color which is debatable. Is it blue? Gray? Green? My wife voted for teal. It looked green enough to me that I wouldn't have used it for a phase.
The question is, if it is green: Is this grandfathered?
Re: Residential Service ca. 1960#152615 11/05/0506:00 PM11/05/0506:00 PM
Just George wrote: "You could mark all three conductors orange in a midpoint-grounded delta system. It just wouldn't be very helpful."
Well, I just looked it up, and my previous statement was not exactly correct. 110.15 states that "only the conductor or busbar having the higher phase voltage to ground shall be durably and permanently marked by an outer finish that is orange in color or by other effective means". I thought I remembered learning that this meant orange couldn't be used anywhere else in the building, but it says only within the system.
Orange is typically used in 480V systems, because buildings with such systems rarely if ever also have a four-wire delta system, and therefore there is no potential for confusion.
Here in my area, orange is absolutely forbidden except in this one area of application. Around here this type of service is fairly common, in contrast to some areas.
If you have a single-phase service, and you are in an area with no local restrictions, you may certainly use orange, as seen here.