I am not sure what you mean by "pull the meter"? It is not legal to mess with the meter. I suspect you don't intend to and that I am just misunderstanding you. If you really need 100 Amp service in the garage, the 6-3 wire should work for that distance. See Table 2 at this link: http://www.metalwebnews.com/howto/ph-conv/ph-conv.html The disconnect box is very good for safety but also servicing anything down stream from the source. Larry

As I think of it, the size of the disconnect isn't an issue because if there's a problem the breaker in the sub-panel would trip. Any you're correct the dude isn't an electrician, but he's going to school and knows just enough to be danger-ous . Nonetheless, he's who the AC installers use, so I figured I'd better use his advice. He also told me that I needed to use a different wire to the unit from the disconnect and that it needed to be in a flexible shield. That wasn't a problem because I had the wire and they'll furnish the shield. Folks down in this neck of the woods can't always seem to get things right. Bob'll say something and then Ray'll say something else. But they got themselves a varmit that demands and will get what he has coming one way or another. The guy that gave the estimate, for example, promised to add an additional vent in the dinning room, which had been added on since original construction (just having air added to an existing central heat system). His work partner said they couldn't do it (and gave a good, understandable reason), but I told him there "ain't no such word as "cain't"; to "find" a way to do it! They have to finish today, so we'll see. I have an idea or so myself.

I think that Austin and I are looking at the same coin. Looking at the other side, a tradesperson that normally does residential (maybe some commercial) might get a chance to do some industrial work. I am sure that there is some learning or relearning that would need to be done. Some details are going to be different. At that point the decision is to bone up on the most relevant sections, or refuse the job because it is not worth the investment. Here is an example that while might not be realistic, I hope is amusing. An electricain is asked to be a subcontractor for an outdoor pool installation in Barrow Alaska. He's never seen an outdoor swimming pool much less built one. He's a busy guy, booked up for the next 6 months. Obviously, he has never been involved in an outdoor pool installation, but he remembers there are specifics that he does not remember or did not learn the detail. Why should he be familiar with that part of the code? Communication is often all about understanding a different point of view. It is perfectly understandable that someone working in industrial situations that has never considered a residential AC unit might be taken aback that he can't see a dedicated disco right next to it. An experienced person standing right next to him, and the compressor, points to the main panel 45 feet away and says that is is right there. You'd never want to have someone looking around in (line of sight) panels in a plant to find the breaker for a 30 HP mixer that requires shutting off for maintenance once a month or cleaning every day. Heck, you would not even consider using the type of disco used for residential HVAC equipment on a fractional HP motor, It is probably not durable enough. That is not what the situation is for the OP and other homeowners. The breaker as a disco is allowed and it works for me even though it might surprise someone who has not thought about it before. In the same vein, I remember a question, I think, in this forum. As it spun out, the OP suggested that the wires in the romex should be colored to indicate which of the two hot busses that they originated on so that when working far from the panel, he could tell. The poster was an electrical engineer. It turns out that he was, as a colleague of mine puts it, a "5V electrical engineer". He is used to looking at low voltage wire looms connecting boards. Electricians and engineers that are in the field working all the time with what he was thinking of for the first time got a good laugh about that.

"How would a HVAC tech know which breaker to flip in order to guarantee he won't be electrocuted?" Hvac techs carry little devices call vom for those situations. "If the circuit panel is right near by, then why would it cost $3000 to add a disconnect box?" It wouldn't. You must be talking about something that has not been discussed here. OP said " The cost would be over $3000 for new panel." Now back to our original program. .