Main disconnect installation question

Yesterday’s inspection of the main disconnect is having me scratch my head a bit as it’s a first for me.
The house is from 1966. I am not understanding the reasons for this installation. An electrician is being recommended due to other issues like exposed live wires in closets, double tap, no GFCIs etc… but I want to understand this box.
There is a main disconnect and right under just the breaker box’s breaker, then the breaker box(in the master closet nice and snug behind clothes :mrgreen:) with all the breakers in it.
Is there a reason for such an installation, instead of the feeders to the breaker box directly connected under the main breaker?

The main disconnect is rate for 125 amps with 2 awg feeder. I was unable to determine the box rating.
The breaker box is rated for 100 amps but was not able to determine the size of the conductors between the breaker and panel.
There was no grounding rod, so I’m assuming the ground metallic conduit is the ground?

Am I over thinking this and the potential reason why the installation is like that is because the breaker box wasn’t rated for 125 amps? or perhaps to have room for more breakers/extra breaker boxes as add-ons are built? :-k

Any help would be appreciated!

In CA, most utility companies require the service disconnect to be on the exterior of a SFR. This may be one explanation.

In any event, the panel inside the home is a sub panel, which requires islation of the neutrals from the egc’s and panel enclosure.

The underground conduit should not be used as the grounding electrode.

And the fact that the main panel is an FPE Stab-lok.

Here, if the panel is > 10’ from the service entrance, a disconnect is required at the feeder. Otherwise, a disconnect can be inside or out, and the main panel is usually in the garage with the meter on the outside wall.

Doesn’t seem that unusual. A 125 amp main panel with available breaker slots. A 100 amp protected feeder to a sub-panel.

Thanks Jeff. Yes, I see the service disconnect to be on the exterior of a SFR, but it was a first for me to see the breaker to the sub panel right there and that is.
So then what is the amp rating to the house (assuming all feeders and box are sized correctly). Is it 125 or 100?

I’m probably just over thinking the situation.

Yes, that was the first thing mentioned

You just answered my question thanks!

The metal conduit would not serve the same purpose as a grounding rod or other electrode.

I couldn’t find any grounding rod anywhere. I differed it all to an electrician and asked the buyer if he wouldn’t mind me talking to the electrician.
There was no ground at any of the receptacle outlets in the house, however, there was a grounding in the detached garage which they converted into a mother in law suite.

Not having a grounding electrode is a problem. Having ungrounded receptacles is also a problem, but the two conditions are completely independent of each other and unrelated…

I would think that whole panel should come out and done right. FPE as well as other issues would make me nervous.