I currently have a 125A sub panel in my steel shop ran from my house 200A service panel. Existing shop sub panel is grounded from house panel to isolated ground bus and also is grounded to shop ground rod and bonded to shop frame.

Going to be running #8 to new panel 40 ft away for a welder and convenience outlets. New panel is bonded to building frame so is it required to run a grounding conductor to new sub and is a ground rod required?

2 Answers 2


I'm assuming this new panel is in the same outbuilding shop as the 125A panel.

Any sub panels fed from the "main" panel for a structure (in this case the existing 125A panel is the main panel for your shop) should be grounded with a dedicated grounding conductor in addition to the hot and neutral conductors. So yes, you must run a ground wire to the new panel.

Note that connecting your panels to other metallic things like the metal building (or copper pipes, etc.) does NOT count as grounding. From a safety standpoint they are irrelevant. Your metal building is probably grounded to your existing panel/ground, not the other way around.


No need for an additional grounding rod. Simply pull a 4 wire feeder (hot, hot, neutral, ground), isolate the grounded (neutral) conductor and bar, and bond the enclosure to the grounding bar and conductor.

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