Funky installation of sub-panel

#1

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.

file:///C:/DOCUME%7E1/1/LOCALS%7E1/Temp/moz-screenshot.jpg

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?

#2

If it’s a detached structure, it requires its own grounding electrode, no matter if it’s a 3-wire or 4-wire feed (there is an exception to that rule for a single branch circuit).

AL can be used as the grounding electrode conductor (or any other type of conductor for that matter).

#3

John, just as a point of information, if the #10’s on the 40 amp breaker you mentioned were for the welder circuit, keep in mind that overcurrent protection for welders and welder circuits are determined by Article 630, and may be sized at up to 300% of the conductor rating.

#4

Regarding the GEC… Art. 250.64 (A) Aluminum grounding electrode conductors shall not be terminated within 18 inches of the earth.

#5

OK, sorry about the B+W pdf’s, BTW.

Is it acceptable to run 240 vac by way of triplex, where the nuetral is uninsulated? :neutral:

#6

Brian, the 40 amp breaker is a main shutoff and the circuit dedicated to the welder is a 30 amp. My feeling is that while this worked OK for years, there has been a shock hazard because of the inadequate grounding and maybe a fire hazard from the light supply conductors and the corrosion in the panel.

The other shock hazard I’m asking about, is it OK to have an uninsulated nuetral, using triplex to supply 240 vac? I could look this up, but think the educational factor here is good for all.

Check out the welding cables. Do not hold the stinger in your right and the ground clamp in your left simultaneously, while standing on the bare welding cables in your sneakers! :eek: