Backfeeding a main breaker panel

Question

Is the following allowed by NEC?

• A main breaker panel is used as a main panel in a house.
• The hot wires from the meter go to a breaker at an arbitrary branch location on the panel thereby backfeeding the panel through this breaker. This breaker is clearly marked as "SERVICE DISCONNECT".
• The factory installed main breaker in the panel is not used but is not physically removed. Instead it is clearly labelled as something like "NOT USED".

Does the code allow backfeeding a main panel as opposed to a sub panel?

I understand that the backfeeding breaker would need to be fastened with a retainer, which brings up this question. Do they even make retainers that work with branch breakers in a main breaker panel? Or are the retainers only made for main lug panels where there is more of an expectation that the panel will be backfed?

The particular main breaker panel I have in mind is this:
GE PowerMark Gold 200-Amp 32-Spaces 40-Circuit Indoor Main Breaker Load Center, Model # TM3220CCU2K
https://www.lowes.com/pd/GE-200-Amp-32-Spaces-40-Circuit-Main-Breaker-Load-Center-Value-Pack/1001089
Is there a means to clamp down a branch breaker on this panel?

The purpose of all of this is to be able to use a 200 amp main breaker panel on a 100 amp service while retaining the ability to easily upgrade to 200 amps later if need be.

I want to end up with a main breaker panel if and when I upgrade to 200 amp. I would prefer not to use a main lug panel.

I would much prefer not to disturb the factory installed 200 amp main breaker. However I would agree to temporarily remove it until it is needed if this was the only issue.

I do not want to spend money on replacing the 200 amp main breaker at the top of the panel with a 100 amp variant, if one is even available for this panel.

Putting another panel or a disconnect between this panel and the meter in order to limit the current to 100 amp is not an option for me.

The solution I described would be the most useful for me. I believe it is electrically sound, but I am unsure if it is up to code.

Answer 1

If it were me, I would put in a 100A main breaker, assuming one is available, save the 200A for the future and be done.

This should be OK to do as you described. Devices to hold down branch breakers are routinely used with a generator and an interlock. In fact, if you insist on doing a backfeed, determine which breaker position (left or right but always right below the main breaker) can be used with an interlock and put the backfeed breaker in that space. That way if you ever want a generator hookup after getting 200A service you will have the space available. If you pick some arbitrary other location then you'll have to do some rearranging to make that work.

I would put the neutral on the neutral bar. Putting hot wires on a branch breaker and neutral on main lug (or for that matter hots on main and neutral on neutral bar) will be confusing and possibly raise questions with the inspector.

Answer 2

Do they even make retainers that work with branch breakers in a main breaker panel? Or are the retainers only made for main lug panels where there is more of an expectation that the panel will be backfed?

You bet they do. Because people put generator interlocks in main panels, and the generator feed breaker needs to be tied down.

Your proposal is fine.

One reason to leave the 200A main in place might be that you need a set of "feed through lugs" to feed a 100A feeder to a subpanel.