3/8" flex is not generally permitted for branch circuit wiring. Are you sure that it is flex and not armored cable or metal clad cable? armored cable & MC Cable have conductors installed when the cable is manufactured. Flex is made empty and wires are installed in the field.

So the answers are no, no, yes (very little), personal preference/availability, try a magnet, if it is 3/8" flex, its a violation.

I am not sure of anything at this point. The walls were closed up without being inspected. The inspectors are noncomittal - they don't want to be responsible for telling the contractor to remove the backsplash and open the wall to see it.

We had never seen stud notching before, so it made an impression on us. My husband had thought it was prewired, but, then, the whole kitchen was supposedly rewired with a different gauge of wire after inspections on 12/10. There was lots of rolls of wire everywhere - I am not sure what happened there.

Is it possible to tell what the conduit/flex situation is if we remove a receptacle from the wall?

Could metal clad cable be re-wired after the walls are closed up?

Both MC cable and AC cable have a spiral armor and are available in steel or aluminum armor.

The NEC makes no distinction between the metal used for the armor for residential applications.

They all fall under the same installation rules and require metal plates in wood studs if they pass through a stud less than 1.25 inches from the face of the stud.

A notch would require an approved metal plate at every stud.
No protection is required between the studs.
A nail or screw would simply move the cable and not penetrate.

"There was lots of rolls of wire everywhere"

Rolls of wire or rolls of cable?

While they could have used flexible metal conduit and pulled wires after the conduit was installed, that would be an incredibly expensive way to install residential wiring.
The labor would be horrendous.

It might be best to let them finsih the work and leave.

Do NOT pay any final bill.

Hire an electrician and have them inspect, correct, and finish the job.

You can deduct the costs of re-doing incorrect wiring from any bill the GC cares to tender.

This type of thing is liable to devolve into a real fight, and even involve an attorney.

It sounds like the AHJ is at beast asleep at the switch, and at worst incompetent or has been paid off.

It might be time to talk to the head of the building inspectors.

Thank you, again, for helping me see through the fog. Yes- rolls of cable - - sorry - - it all seems wire-like to a non-contractor like me.

They did use the metal flex and they did seem to be rewiring it all - it took a few days and we are only talking about maybe a dozen outlets.

It doesn't matter WHAT he has. It's not one of the listed conduit types. It must be covered with an 1/8" steel plate. I don't know what he has. He keeps saying strap or bracket. It has to be a 1/8" steel. Plumeria it looks like a piece of metal the width of the stud and perhaps 3" or so long right?

The studs were notched and the flex was put in, held in place with a bracket.

The bracket is not there to hold the flex in place. It would be a lot cheaper to just use a large staple. The bracket is to protect the flex where it passes thru the stud in the notch.

Is conduit required in your area? New York, Chicago?

"It must be covered with an 1/8" steel plate."

1/16 thick, but they are hardened.

It is nearly impossible to drive a nail or screw through them, and even drilling is a tough job.

Romex is fine.

Removing a box from a wall (tiled, like yours) would be messy and difficult.