[...snip...]

At this point I'm really leaning towards putting a sub-panel in the
shop. I want to relocate the wire running to the dryer out to the shop
and use it as the feeder cable. The new sub panel would have a 50 amp
breaker for a main disconnect, a 30 amp breaker feeding new wire run
to the dryer, a 20 amp breaker feeding new wire to run the table saw,
and possibly a few 110v circuits for various outlets throughout the
shop. Any major problems with this plan?


I think it is a good plan, except you might consider getting a
subpanel with more expansion room, so that you don't have to go back
in a few years and increase the size of the subpanel.

In my case I had an electrician replace my old fuse box with a modern
200 amp panel about 15 years back. In my ignorance, I didn't specify
that we should spend a few extra dollars for a panel with plenty of
expansion room.

Since the house is older, I have added a lot of new circuits over the
years, often to reduce the load on the old wiring or to add outside
lights, dedicated circuits for things like the refrigerator, washer,
microwave, etc.

Anyway, I quickly maxed out the panel. When I ripped down my old
garage/utility room and replaced it with a shop worthy space, I got
the biggest Siemens type panel I could (Siemens breakers are widely
available and relatively inexpensive), took that old panel and put it
in the garage as a subpanel. It is nearly full now.

I've looked at the cable that
currently feeds the dryer, it is about 3/4" thick, round, grey and not
labeled - how best to identify it for sure? Would this plan require
any changes inside the main breaker box?

You could open up the outlet box the dryer plugs into and check out
the wires themselves.