Then wiring in my house is old, much of it cloth wiring. The electrical cabling goes from an outdoor main panel down a conduit into the ground and comes out in the crawlspace. I'm wanting to rewire a good portion of my house with new wiring and reroute it through the attic. Is the best approach to run conduit through an exterior wall from the crawlspace to the attic? I'm thinking of using thhn wire. It's all 12 AWG wiring. How much can I run through one such conduit? There a better way to do all of this? Thanks.
Addendum: There really isn't any existing conduit. Some of the wires run through this rubber conduit toward the center of the home, and some wire runs exposed to different parts.
When you say to terminate the wires into a junction box, are you talking about a pull box? How can one terminate 10+ circuits into a junction box?