How to take an external connection from the main supply?
I am thinking of expanding my garage to a two new separated garage with workshop space. I might need two single-phase 240V and 120V circuits in the garage; I believe a 100A panel would be enough.
I have an external service panel with an electric meter outside my house. A 200A main breaker supplies to a 200A sub-panel located in my storeroom where all the house breakers are.
I want to use this outer 200A panel to supply a new circuit to a sub-panel placed in the new garage, but I can't take it into the underground because of the pool and septic system.
I thought of doing this myself with a little help from my electrical service contractors. Is there any reason I shouldn't do this on my own? If so, is there any reason I shouldn't use the existing exterior 200A service panel to supply my new garage?
Any help is welcomed!
Thanks for your advice.