Wiring – Adding a subpanel, but have one question.

It's difficult to tell from the photo if there's even a grounding conductor run along with the two ungrounded (hot) conductors, so you'll have to verify that before you go shopping for supplies. You'll also have to verify that the ungrounded (hot) conductors are the proper size. You said the panel is fed through a 60 ampere breaker, so you'll need at least 6 AWG copper conductors (solid or stranded, it makes no difference).

Shopping

Here's what you're going to need.

• A grounding bus bar.
• 6 AWG copper THWN wire with white or gray insulation, long enough to reach from the main grounded (neutral) bar to second panel grounded (neutral) bar.
• 6 AWG bare or green copper conductor, long enough to reach from the main grounding bar to the second panel grounding bar (which you'll install).

If the current ungrounded (hot) conductors are undersized, you have a couple choices. You can replace them, with appropriate conductors. Or you can install a smaller feeder breaker in the main panel, and down size the grounded and grounding conductors accordingly.

Installation

Once you have the supplies, here's what you're going to do.

• Remove the brass bonding screw from the existing bus bar in the second panel.
• Install the grounding bus bar (the one you purchased), in the panel.
• Move all the grounding conductors from the old grounding bus, to the new grounding bus bar.
• Pull the required conductors between the panels.
• Connect the grounded (neutral) conductor to the grounded (neutral) bar in the main panel.
• Connect the grounding conductor to the grounding bar in the main panel.
• Connect the grounded (neutral) conductor to the grounded (neutral) bar in the second panel.
• Connect the grounding conductor to the new grounding bar in the second panel.
• Connect the grounded (neutral) pigtail from the GFCI breaker, to the grounded (neutral) bar in the second panel.

Now you should be all set.

NOTE: Depending on where the second panel is installed. You may need to install a grounding electrode, and bond the panel to it. Check with your local building department, to determine if this is required.

Since you have a 2" PVC (assuming schedule 80) conduit here, providing 742 mm2 of room for wire fill, and your 3 2AWG wires (assuming THHN/THWN or XHHW here) only take up 66*3 = 198 mm2 of that space, you have plenty of room to stuff a bare wire down the conduit to bond the subpanel and main panel grounding bars together. A 6AWG bare copper wire will do the job, and should be fishable through the conduit with the power to the main panel turned off. Connect it to the ground bar in the main and sub panels, turn the main panel back on, and you're in business. (Of course, if you don't want to play "fishtape wrestler" for a day, you can pay the nearest friendly electrician for that service instead.)

P.S. no, you do not need to remove the ground rod once you install the bonding wire between the two buildings -- in fact, current Code requires outbuildings to have their own earth ground, in addition to the bond back to the main panel's ground. (This is done to keep all the wires to the outbuilding from soaring to some crazy-high voltage in case lightning strikes near the circuit conductors.)