Trying to buy just the exact amount for the job is an exercise in frustration. Those in the business constantly use NM cable and any surplus can be used for (and charged to) a future job. The need for a neutral at every switch location has vastly increased the use of 3- conductor NM-- and with a significant increase in cost as a consequence.

OB? Sounds to me that you are depending on amatures to properly wire what I presume is a new house you are building. First thing you need to do is check on local codes included hard wired smoke alarms. In our area, all new construction must be wired with 12ga wire and 20amp breakers. A journeyman electrician usually works under the license of master electrician who is responsible for his/her work.

Do you have a lighting design? Location and # of switches? How big is your service going to be? What HVAC technology are you using?

You aren't buying enough larger sizes (feeders,hot tub, etc.) to save anything in "bulk". Use your Lowes card for 5% discount if you don't have a jobber/wholesale connection.

A rule of thumb is 1ft per 1cf of space but until you know 14ga vs 12ga, 2-wire vs 3-wire, which NEC code your state/city is using, etc. you can't do much pre-buying.

You mentioned "separate workshop". Is that physically separate from the house? An shed of some type? That will require additional investigation.

Going to wire RG6 or any Cat5e/cat6 to the rooms as well?

And check codes for GFCIs/AFCIs and proper bonding. Just because your Dad has done some wiring in the past, don't get yourself into a problem when it comes time for the inspection. Codes change.

Can I presume you are in Texas? Texas has a statewide mandate that all the local jurisdictions adopt the 2011 NEC.
This means TR receptacles, AFCIs in almost all the living spaces, neutrals in switch boxes, as the two previous posters have alluded.

Getting some proper help at the design stage can avoid you buying a lot of stuff you won't be legally able to use, even if your journeyman friend was smart enough to keep you from installing it in a non-compliant manner. I've seen plenty of plans (even done by professional architects) that have pages of violations of the code if they were actually built as drawn (It's easy to draw them, harder to get them through inspection).

If you're going to put more than one circuit in your workshop, it's going to take it's own grounding system, and accessory buildings on grade take GFCI protection as well.

Hot tubs/spas and pools have their own article in the code and requires specific attention to detail not only because the rules for the wiring running to it are different but there are very specific safety requirements when you're going to immerse your family into a pool of water that you've wired up.

"We are an OB and plan to break ground in a month"

What does being an obstretician have to do with breaking ground?
Just curious

If your main question is "how much wire should I buy" then I would say this project is not for you. I rarely take that stance and usually support DIYers instead... but here it's not just how much - but what kind, how much of 12/2, 12/3, 14/2, 14/3, 10/3, and even bigger... what kind of panel, how many boxes, metal vs plastic, what knock-out connectors, lighting requirements, Title-24... it just goes so far beyond how much cable to buy.

I'm not an electrician... but I'd be comfortable doing a whole house, having progressed from small projects over the last 10 yrs... but I started small... installing a bar, some outlets, moved on to subpanels, then main panels, then doing an addition, basement remodel, etc. All along the way I talked to inspectors and others about what I'd done wrong, what to improve, etc. It seems like you're jumping into the hugest possible residential job as your first wiring project. 3600sf is an immense house. Why are you doing new construction on a house and not having it wired by the GC? He would have it knocked out in a couple days.

To answer your question, I would start w the biggest roll HD or Lowes sells of 12/2 and 14/2. 500' I think it is. And evaluate where I'll need 12/3 or 14/3. Maybe the 250' rolls of those. Depending on how many 3-way switches you have to install, maybe a big roll of 14/3 as well. This is all assuming you're not in a city that requires conduit instead.

OB = Owner Builder not obstetrician.
The reason his GC isn't doing it is there is no GC.

I like to think I'm pretty competent for a devoted amateur but I'm not sure I'd take on wiring a whole house without some professional guidance.

There are estimating books that might give the OP some guidance.

And however much you estimate, you will NOT have enough.

Unless money is VERY tight, go for receptacles every 6 feet on the walls instead of the code minimum of 12 feet apart.

It greatly minimizes the need for extension cords.

This post was edited by brickeyee on Thu, Apr 25, 13 at 15:13

1100 sq. ft. addition in 2012 we used;

1000 ft 12-2 for outlets

1000 ft 14-2 and 500 ft 14-3 for lighting

measure for electric range 6-3, electric dryer 10-3, electric water heater 10-2.