Looking for a direction on this one. The main disconnect is located outside below the electric meter. The main panel is located inside and also has a main breaker. The exterior disconnect has an enclosure ground. The inside panel doesn’t. The inside panel has a 4 wire feed, (which I rarely see here) coming from the exterior disconnect. In my mind the interior panel is a sub panel and the grounds and neutrals should be separated.
Am I correct on this or should the interior panel have its own ground rod and have the grounds and neutrals bonded?
The GEC’s from the grounding electrodes must go to the service disconnect on the outside or to some other point upstream of the service disconnect. You are correct that the interior panel is now a sub-panel and the neutrals and EGC buses must be separate and the neutral bus must not be bonded to the enclosure. There is some ugly DIY looking electrical work in that panel.
You may remember a previous post I had where there was an “auxiliary” ground coming from the main disconnect but it was not the main ground. I see them more and more often it seems. From his photo, how could we confirm?
Thanks for the feedback guys. I have already referred it to an electrician. I am just trying to learn more about it. The GEC comes off the ground rod (partially visible) and goes to the exterior disconnect. I was wondering if the 4th wire, coming from the exterior disconnect to the interior panel shiny aluminum on the right side) was serving in place of the ground rod for the interior panel.
That 4th conductor that you’ve mentioned is the EGC (equipment grounding conductor) in the panel feeder. Since this panel is in/on the same structure as the service disconnect there is no need to connect a grounding electrode to the sub-panel. The GEC going to the service disconnect is correct.
Just to clarify, the conductor going through the IBT (intersystem bonding termination device) in the photo is the GEC which is likely going to an electrode?
Thanks again Robert, I thought the 4th conductor was the EGC for the sub-panel in the home. But the grounds and neutrals still have to be separated in the sub-panel? I am aware I don’t have to understand this, but the more I understand something the easier it gets to inspect correctly.
No problem feel free to ask questions even if it is outside of the scope of a home inspection. And yes the neutrals and EGC’s must be separate in a sub-panel.
I hate to bring this up again, but every time I get it straight in my head I see something I haven’t seen yet. This panel is the same setup as my original question. The main disconnect is mounted to the house, under the electric meter. The disconnect doesn’t have an EGC to the ground rod but does have a four wire feed to the dwelling panel (200 amp in basement). The dwelling panel has the EGC that is connected to the ground rod. The fourth wire coming from the disconnect (green wire) is connected to the ground bus in the dwelling panel, right above the EGC. The neutrals and grounds are separated in the dwelling panel.
Will this work? I see in Roberts earlier post that the EGC has to be upstream of the disconnect, which this isn’t.
It seems to me that a lightening strike to the electric mast or a power surge from the grid could energize/damage the main panel before making it to ground with this setup.
I think that you meant GEC (grounding electrode conductor) not EGC (equipment grounding conductor). Looks like the service disconnect under the meter is good. I do see a large green conductor where does that go to the inside panel? The bare conductor in the SER cable would be the feeder EGC to the inside panel so the green conductor would then be a redundant EGC. Any GEC going to the inside panel would be incorrect.
Thanks Robert,
I think the terminology and abbreviations are part of what makes this confusing. The grounding electrode conductor (large bare copper wire) is connected to a ground rod and to the inside panel on the ground bus. The green conductor from the disconnect goes to the ground bus right below the GEC. From the previous post and reading, I believe the service disconnect has to have the GEC connected to the ground rod. This one doesn’t, The GEC and ground rod are connected to the inside panel.
That is correct, the connection of the GEC to the neutral needs to be at or upstream of the point where the MBJ (main bonding jumper) is installed. It cannot be in the sub-panel which is downstream of the MBJ. I don’t know why the green conductor is even there. The EGC for the feeder is clearly the large bare aluminum conductor within the SE cable.
