Proper subplanel parameters.

Hi,
I'm remodeling my kitchen/hallway/powder room combination.
On the one hand, I just had a new 200amp service put in and a new 40circuit box installed and it's only half full. And it's also only 40ft away from the kitchen, on average.
But I still want a subpanel for the kitchen. My main rationale is neatness, It's an old house and there are several generations of ad hoc electrical improvements and I have literally tens of dead wires in the walls that go nowhere, there are wires from the 30's, 60's and 80's, etc. It is especially messy around the new box. I would have to have 10 or so more wires running all the way back to the box. So please, don't talk me out of doing a subpanel, I'm committed to doing it (I have additional reasons for doing it, too).
Here's what my kitchen will have: 1. A dual fuel range (requiring 30amps for the oven) 2. A heater/vent combination in the power room. 3. Possibly an underfloor heating mat 4. Microwave/convection oven/garbage disposal/toaster oven/tv/dvd/ outlets galore
Main question: How many amps should I have going into the subpanel?
And then there is something I don't get: does the subpanel have it's own main breaker or does it rely on the breaker that it comes off of in the main panel?
Many thank in advance,
Aaron
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*A 50 amp sub-panel feed would suffice, but I would go with a 70 amp (#4 wire) to allow for future expansion. The breaker at the main panel is all that is needed, but there is nothing wrong with having a main in your sub-panel.
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On Thu, 18 Dec 2008 17:34:59 -0500, "John Grabowski"

You can really get 85A out of #4 if you run wire in pipe but a cable like Romex (MC, or SER) is 70. You do not need a disconnect in the sub, the line side breaker on the feeder is sufficient. Just remember this is 4 wires (3 #4s and a #8 for the equipment grounding conductor) Use a separate grounding bus that you will have to buy.
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70 a sub can go on #6
#4 will get you a 100a sub.
s

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On Thu, 18 Dec 2008 19:07:16 -0600, "Steve Barker"

Thank you for playing our game
How did you get that? 310.15(B)(6) does not apply to sub panels and you can't use the 90c column of 310.16.
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