Electrical

[Jeff000]

You would be surprised on the small panels I've seen in newer houses lately. If you panel is truly full most manufactures have double breakers available in the 15 and 20amp sizes that allow 2 15 or 20amp circuits per slot, or even a combo of the 2. I know Square D and Cutler do for sure as I've had to use both on my own house and garage.

I'm not great at using the NEC code book, but the CEC requires that at least 2 extra spaces be available in all newly installed panels. I wouldn't be surprised to see that in the NEC too, just not sure where to look for it.

But yes the slim breakers are a good option where available.

Running wiring outside and then just sticking it under the siding is NOT legal.. He has already been told that he should get a qualified electrician...

And I wouldn't ever run wiring outside or aquarium circuits (receptables there or not) without GFI protection of some sort.

teck 90 comes to mind....

Depending what code cycle the OP is using I know that AFC or GFI has to be used. But just because a cable goes outside does not mean that being GFI protected is nessisary or needed.
Running GFI for lighting is pointless really, it will not protect the secondary side of ballasts.