I had a lightning strike near my house that damaged the electric in my shed and now I need to replace the subpanel. I have a question about the groundbar.
In the subpanel I am replacing the grouond and neutral bars were isolated, but the ground bar was not bonded to the subpanel itself. When I replace this subpanel should I attach a bonding screw from the ground bar to the subpanel?
Thanks,
Yes the grounding side needs to be bonded to the metal case the neutral or grounded side is isolated from the case. The only place both the grounding and grounded conductors are connected together is in the main but both panels need the case bonded to the grounding buss.
I recommend you leave both of those as neutral bars, and add some accessory ground bars, which are $6-ish, each. Otherwise you will run out of neutral bar locations long before you run out of spaces. Neutral bars are hard to add.
At the very least, use the left one for neutrals. It has a better chance of being able to support all the breakers this panel can support. You can never double-tap neutral lugs. But many panels will allow you to triple-tap ground bars, which means you would be able to get enough grounds out of the right side bar.
Also, since this is an outbuilding, it needs a disconnect switch. Where is it? If you have none, and this panel is convertible to main breaker, that would suffice. Otherwise you'll need to either backfeed a breaker, fit a separate disconnect switch (generally more expensive) or use a different panel.
Neutrals are precious as you can't "double up" neutral wires, and most panels don't support accessory neutral bars. So, instead of using the factory split neutral facility, I would fit the panel with an Eaton GBK10, move the grounding wires to it, then reinstall the cross bonding strap between the two neutral bars. (P.S. if you threw it away, just poke your local Eaton distributor and ask them to order in a 80-20657-15; if they give you a puzzled look, ask them to email the Eaton TRC re: "Cross Strap Replacement attn: Hannah", and the TRC should get back to them with ordering instructions for the part.)
Once that's done, you'll want to address the lack of a disconnecting means for the outbuilding. This can be done using a BREQS125 hold-down kit and a BR2100 breaker used as a disconnect switch. Finally, you'll need to take some #6 bare copper and run it from the panel grounding bar to two 8' ground rods driven into the ground a minimum of 6-8' apart; that way, your shed's electrical system will stand a better chance of surviving the next lightning strike.
