I am re wiring my 100 year old house. Trying to pull new circuits into a new panel box while leaving the existing 100 amp service up until I change over. I wired the entire upstairs outlet to one circuit and the lights to a separate one, however I used 14-2 wire because I had it.. can I just use a 15 amp circuit breaker on both of those circuits?

If you used 14-2, it has to be 15 amp breaker, if you used #12 you could place on a 20 smp breaker.
If it gets cold up there, I would have a 20 amp circuit as well(pair of #12's), for a plug in heater.

The entire second floor on only two circuits?? How many rooms?

Very small just 2 bedrooms and an open floor space.. So in all I have 3 lights with switch legs and 13 outlets.

\Sounds like I should spread the outlets out in the J box so all 13 aren't on the same circuit, since the lighting circuit is not full

Yeah, I would have split the two rooms up on the two circuits.
I am not one of those who always keeps ALL lighting and receptacles separate. In situations like this I see absolutely no reason to.

Do these bedrooms have to use arc fault breakers? Arethese for outside and bedroom use only.

Please see 2008 NEC code # 210.12.

ALL -Family rooms, dining rooms, living rooms, parlors, libraries, dens, sunrooms, recreation rooms, closets, hallways or similar areas.

Since you are upgrading your Main Service Panel, you will lose the "Grandfather" clause that protected the original Service Panel.

Since you are upgrading tour Main Service Panel, you will lose the "Grandfather" clause that protected the original Service Panel.What do you mean by this? Are you saying AFCIs would have to be used for a panel change?

If so then this would be pretty rare. I have only heard of this being required in one or two areas.
Definitely something I would check.

Stan,

Is it not true that when you upgrade your panel with new electrical service, that the new wiring must be in accord with the current recognized level of code being used by the LAHJ?

From my perspective, which may be skewed, that is what he is doing. Quote, "I am re wiring my 100 year old house."

I guess I should have been more specific.

A panel change typically has no bearing on the existing branch circuit wiring.

Adding new circuits yes, you absolutely do have to follow current codes.

Okay, you bring up a good question for me.

If I just do a panel change because, for example, the neutral bus bar has rusted. Then I am still within the Grandfather protection, correct?

If I add circuits to an existing panel, the new circuits have to be up to current level code, correct?

If I take the panel from 100 amp service to 200 amp service, the new panel must be connected according to current level code, correct?

Just because a service entrance is changed, for any reason, does not require the entire home to be upgraded to current code.

Only new circuits need to comply with new code. Or if any space is renovated.

Thank you.