An unfinished basement requires at least one GFI protected receptacle. In almost every case, the basement is a "damp" location, so ordinary boxes can be used. The furnace -even if it is gas heat, with only a small blower- needs to be on its' own circuit. It does not need to be GFI protected. Indeed, where a spark igniter is used, I would worry about nuisance tripping of the GFI here. While there is no code requirement, I would suggest a separate circuit for any sump pump that might be present. Assumint this is a basement- and not a crawl space- the lights can be part of any lighting circuit, and need not be GFI protected.
Where I grew up (Ohio) basements were considered a damp area. Now that I'm in Seattle, every one gives me a funny look when I suggest that a basement is a damp area. Maybe its because the whole area is damp so what is damp to you is normal for us. Perhaps its because many basements here are daylight basements (one wall at grade level). But most here seem to consider damp areas to be REALLY damp areas, like the area under a dock or maybe an unheated building.
[This message has been edited by markp (edited 12-04-2005).]
Well, one might argue that I am unqualified to comment, since basements are rare as hen's teeth around here, but I've lived in basement territory and I can read the NEC, so here goes:
1. You have to have at least one lampholder, switched from the top of the stairs. If you choose to have more than one light, the remainder can be pullchains if you so desire (I recommend having them all on one switch, but that's just me). Lighting does not have to be GFCI-protected, and indeed I don't recommend it.
2. My understanding is that the NEC considers finished-basement spaces to be dry locations, and unfinished spaces to be damp locations. You know and I know that that all depends on how well the basement is built, but finished spaces do not require GFCI-protected receptacles, and unfinished spaces do.
3. Other than the GFCI requirement, the damp location thing doesn't affect the selection of wiring methods or enclosure types. I have never heard of dry-location boxes being rejected in a basement, unless they were in a sump area. Unprotected NM below ceiling level, however, is usually rejected on the grounds that it is "subject to physical damage". If you sleeve the NM in EMT wherever it drops down a wall, this is usually satisfactory.
4. Nothing but the receptacles are required to be GFCI-protected. Reno's comment about an individual branch-circuit for a combustion appliance applies regardless of whether or not it is located in the basement, and GFCI protection is not required. If you have a washer, dryer, refrigerator or freezer down there, you may have a single (not duplex) receptacle for it, which does not have GFCI protection (not all jurisdictions enforce single receptacles). If you have more than one general-purpose receptacle in the basement, it must be GFCI-protected.
5. The GFCI requirement only applies to 125V, 15- and 20-A receptacles. If you have power tools down there that require 240V, GFCI protection is not required by the NEC, but I do recommend it anyway.
The reason I referred to a basement as a 'damp' location is because the NEC includes, in its' definitions of damp locations, a reference to masonry (or concrete) in direct contact with the earth. In an unfinished basement, this would more than likely be whaer a receptacle would be mounted.