- U.S.A. Voltages/power present.
- My house has a 125A Power Mains breaker at the street.
- A buried line runs from the street breaker to my main panel on exterior wall outside of house.
- The main panel has 3 220VAC breakers: a 30A, 40A, and 50A.
- I have proven the 30A runs to a 3-prong 220VAC Electrical Dryer plug.
- I have proven the 50A runs to the existing subpanel in the attached garage which has 11 breakers ranging from 15A to 25A (This panel is full).
- I presume the 40A circuit runs to the A/C compressor unit.
- The existing subpanel in the garage has two conduits (or knockouts), a small one which contains the power feed from the 50A breaker outside, and a large one which contains the wire bundle that services the fixtures and outlets in the house.
- The power feed line in the existing subpanel is wired as follows:
- L is landed on the L bussbar terminal screw (The bussbar is fully populated with breakers)
- N is landed on the N bussbar terminal screw
- G is uninsulated, and (oddly) not landed anywhere I presume this isn't to code.
I need to add a new (additional) subpanel in the garage for additional breakers.
Assuming this is up to code, I intend to parallel the new subpanel with the existing one, by:
- Properly landing the unlanded G in the existing subpanel
- Landing a new L line which will supply the new subpanel on the same bussbar terminal (screw) in the existing subpanel that the existing L line is landed. This new line will run to the subpanel as a power supply line.
- Landing a new N line the same way.
If I parallel a new subpanel this way, can I route the tie-in to the new subpanel through the larger knockout which contains the wiring to the outlets and fixtures, or must I route the tie-in to the new subpanel through the same small conduit that supplies the existing subpanel?
What parts of this plan are not up-to-code (assuming NEC 2008, or 2011)?
Regardless of code, what parts are unsafe?