Garage Wiring

[MRCLUNKER]

I am currently replacing my driveway and garage floor. In a year or so I plan on adding on a garage and workshop to my existing garage. currently I have 200 amp service to my house on the East wall. My garage is on the west side of my house with 60 amp service running off of the 200 amp service and this box is located on the East wall of the garage. My question is this; can I place a 100 amp service box on the west wall of the garage
and run this off of the 200 amp service and in addition disconnect the 60 amp service and run it off of the 100 amp service. The wires will run under the existing garage floor. Also do I need two separate conduits under the floor for the two cables and what size and type of conduit is recommended. Is there special wire specs required for the underground wire. I know this is a bit convoluted so I attached a jpg drawing. Any help or comments would be appreciated. Thanks

[HayZee518]

OK, both boxes in the garage will be classed as sub panel boxes. What you'll need for a feed for the 100 amp will be three THW/THWN #2 Aluminum cable in 1 1/2 inch conduit - pvc, rigid. You'll need to drive two ground rods at the external garage location. A #6 bare copper will be the ground wire size for the 100 amp. The panelbox adjacent to the 100 amp - the 60 amp is also classed as a sub panel. It also needs a #6 bare ground to the panel. A 60 amp feeder can be #6/3 with ground romex or three #6's THHN/THWN copper cables in a 1 inch conduit, again metal or pvc. Both sub panels need an isolated neutral strip and the addition of an auxillary ground strip to which the driven ground wire will attach.

[MRCLUNKER]

Thanks for the info. Hayzee518

You gave me all the information I needed.
This site is great!!

[normel]

According to your drawings, the existing garage and the proposed new garage are both attached to the house. If this is the case, you must run four wires between the main and the subpanels (two hots, neutral, ground). You DO NOT have to drive new ground rods. If you have space in the existing main, run the new subpanel from there and leave the existing as is.