This is a subpanel in a workshop where the owner ran his antique Forney arc welder amongst other things. He ran triplex wire, 2 insulated and 1 unisulated Al from the back of the house thru the trees to the shop about 80 feet.
Besides the cobwebs and rust in the panel, we see #10 copper supplying 40 amps.
But how about the aluminum grounding conductor, a left-over chunk of the triplex? The second picture shows the other end of that GC, parts of which were buried under needles and leaves for 15 years and only the steel core is left to carry the juice.
This is not from an inspection, it’s a reno in progress and we have ripped out the funky wiring to the shop.
My question? If there was a four-strand feed from the house, 3 insulated and one grounding wire, does the sub panel still need to be grounded to a rod? Is Al ever acceptable for grounding?