Had to choose between a 200 amp panel upgrade or a subpanel for a new garage workshop

The homeowner wanted a full EV charger, a welder, and a dust collection system running at once... so the load calc came out to 140 amps just for the garage. My choice was a whole house upgrade from their old 100 amp service for about $4,200, or installing a 125 amp subpanel fed from the main for roughly $1,800. I went with the subpanel because the existing service wires were in good shape and the main house load was still light. It worked out, but I'm wondering if I should have pushed harder for the full upgrade for future proofing. Has anyone else had a garage load push them right to the edge of what a subpanel can handle?

2 comments

2 Comments

jones.blake9d ago

Future proofing is a real concern, but you also have to think about the panel's physical space. That old 100 amp main might only have a few open slots left. Even with a subpanel, you're stuck if the main box fills up with other circuits later. I've seen people add a heat pump or hot tub and suddenly need a whole new service anyway because there's no room to land the wires. Your load calc is okay now, but the box itself could be the next limit.

king.aaron9d ago

That old panel space fills up faster than you'd think.