Can someone please explain the following question (questions an inspector should ask themselves during the inspection) included in the Subpanel information from the Residential Electrical Inspection course?
Is the neutral bus isolated from the panel enclosure?
Thanks!
It is one of the requirements in a remote distribution panel (aka, subpanel) for the neutral bus to be separated from the panel enclosure.
What did this course teach you about this scenario? Was it unclear? If so, what are you unclear about? That can help us drill down on answering your question.
There are some subpanels that this doesn’t apply to, such as:
So in this question you’re referring to a sub-panel. I would start with identifying what the panel is. If you’ve concluded that it is a sub-panel then you would need to check that the neutral bus is not bonded to the enclosure meaning no green screw, bonding strap, wire jumper, etc.
One exception could be a sub-panel installed in a remote structure prior to the adoption of the 2008 NEC as mentioned in David’s post.
That’s the first question in my mind before I open a subpanel to inspect it.
I want to see the ground bus bonded to the panel, and the neutral bus isolated from the panel and not have any ground wires attached to it.
Here’s the answer I got from AI that might, or might not, help you to understand this situation. 
why are the neutral wires isolated in a subpanel - Google Search
Neutral wires in a subpanel are isolated from the ground wires to prevent current from unintentionally flowing through the grounding system during normal operation and to ensure a dedicated path for fault current to flow in the event of a ground fault. This separation prevents shock hazards and ensures proper functioning of circuit breakers.
This was a subpanel that I recently inspected that had this defect, among others, that I found in the panel.
That mess has Harry Homeowner writtten all over it. The separate EGC bus is missing and the neutral is not bonded so it is possible that the enclosure could become energized.
I agree that’s what Harry Homeowner electrical work looks like, but there was also a new panel installed and the claim of an “updated electrical system”. The company that did the work slapped their sticker on the panel cover, and they are known to those in the business locally to be hacks, and they proved themselves once again.
This was my first clue.
Here’s the distribution panel they installed, not bad, but notice the grounds and neutrals are seperated in this panel, yet they weren’t in the subpanel. Must’ve had the FNG doing the sub. 
And then there was the live K&T I found. 
So helpful. Not sure how I missed this pic in the content. Thx!
Just WOW! Thanks for the share. This helps a lot.
