Today I came across a panel on a home built in the 80s. It was a main service disconnect combined with the main house panel, on the exterior of the home next to the meter box.
The issue I’m seeing is, all of the grounding wires, including one going to the AC condenser that was installed in 1998, all go to the one large lug that is usually where the ground or neutral wire is connected that goes into the inside panel when the panels are separate. I do not believe this is code, and flagged it, but before I publish the report, I started second guessing myself and wanted some feedback from some of you. Let me know your thoughts on this one.
Here is my comment in the report:
“The main service panel is combined with the home’s main disconnect in one unit. Multiple equipment grounding conductors (ground wires) are terminated under a single large terminal lug on the grounding bus bar. This type of terminal is typically intended for a single conductor, usually the main service ground or neutral. This configuration may not comply with current electrical code or the panel manufacturer’s listing, as terminals must be rated for multiple conductors of that type and size. Recommend evaluation and correction by a licensed electrician to ensure safe and code-compliant grounding connections.”
As for all those grounds under the Ground main lug, there are sold and strand conductors. Not appropriate I feel.
National Electrical Code (NEC) allows up to three grounding conductors to terminate under one lug on a grounding bus, provided it is listed for such use. This is covered under section 110.3(b) of the NEC.
AI: Grounding conductors (both copper and aluminum) can be terminated under a single lug on a grounding busbar, with a maximum of three conductors per lug, provided the grounding bus and lugs are designed for such terminations.
That’s irrelevant unless you are a code compliance inspector and the house was built under the current building codes. Depending on the age of the house, there could be dozens of things that do not comply with current building codes.
You should explain what the consequences are of any defects or deficiencies that you cite in an inspection report. That’s the most important part of any inspection report commentary.
In Utah, most homes have 2 panels, one outside with the main disconnect and occasionally a few breakers for misc items, and one inside the home for the rest of the breakers. This house had all of them combined in a single panel, something we do not see often in Utah.
I understand we are not code inspectors. That sentence wasn’t necessary in my comment. Utah has no licensing or compliance requirements for home inspectors. I was a general contractor for years and a city code inspector, so I reference code related to my findings in my report. Guess I shouldn’t be doing that.
I appreciate the response, even if it doesn’t answer my question.
In short the large terminal cannot have multiple conductors terminated in it. Also the neutral bus can only have a single neutral conductor per terminal hole. There may be more than one EGC per hole in the neutral bus depending on the panel listing.
Anyway, your question has been answered by Jim. I liked what George added to the conversation because the lug question was quickly resolved. The panel has several other issues that might arise in the comment section. I think that will be helpful as well.
