How to wire a disconnect switch to main?
Never had to install one of these before, a friend is asking, I don’t know the answer.
He is moving is main 200A panel to a new location. Code requires he install a separate disconnect switch under the meter socket box. The Main 200A then becomes a subpanel for all intents and purposes and the bonding screw is removed from the Main. 4-wire cable is then run between the Main and Disconnect switch at the meter.
I told him inside the Main he needs to install the 4th ground wire to a lug mounted on the grouind bar attached to the cabinet, not the neutral bars. The neutral wire is to attach to the normal neutral lug, hots the same as well. But at the disconnect switch I’m not sure how that gets wired.
At the disconnect there are 3 large lugs and 2 small lugs. The 3 lugs I’m sure are for 3 of the wires going to the Main of course. But, whre in the disconnect does the 4th grounding wire go? Inside one of the smaller screw type lugs? Also, the bare No.4 grounded wire to the ground rod, does it go in one of the smaller screw lugs, the same as it does in a Main panel? In the disconnect there is a green bonding screw. I told him he needs the bonding screw in the disconnect, the disconnect becomes the Main panel in essense and that that was why.
Does anyone have a link to a wiring diagram of this kind of arrangement? Seeing it will explain it better to me.
Replies
You pretty much said it all. You've got it right. You just wire the disconnect as you would the original 200 amp panel and then wire the 200 amp panel as a sub panel.
Your grounding wires are connected in the disconnect as they were in the original panel.
You may need to run the feed from the disconnect to the 200 amp panel in conduit and use individual wires.
You will have to use bonding bushings on the ends of the conduit everywhere if you are using metal conduit to connect the boxes.