Yes it is #10 sow cable. This panel also has emt, aluminum flex, liquid tight flex, mc cable and romex cable ran to it. Whatever was laying in the back of their pickup truck got used. Too bad they didn't have any connectors.
When they kept adding more and more stuff on the circuits and the 20amp breakers started tripping from overload they just upped the breakers to 30amps and kept adding more load. I measured over 25 amps on a lot of these circuits.
When they called they said they had smoke comming out of one of the switches that someone at the bar tried to replace. I took photos and wrote up a nice letter stateing what a disaster and fire hazard all this stuff was and had the manager sign a copy of the letter and the photos. I told him he needs to rip everything out and start over with the wiring. The place used to be a restuarant and was converted to a bar. He also told me some employees have complained about being shocked.