Okay, let's break down this scenario and address your question about avoiding the 4-wire feed and the grouping requirement.

Understanding the Problem

You have: A 400A meter socket with double lugs. Two 200A panels, each with a main breaker, serving as service disconnecting means. Service conductors run outside the building and then penetrate the wall to the panels. The core question: Can you legally use a 3-wire feed (two hots and a neutral) from the meter socket to each panel instead of a 4-wire feed (two hots, neutral, and ground)? You're also asking if you can avoid grouping the disconnects.

The Short Answer: Generally, NO. With very limited exceptions, you CANNOT use a 3-wire feed to the panels AND comply with the NEC. Grouping is a MAJOR hurdle.

Why a 4-Wire Feed is Typically Required1. Equipment Grounding (250.32, 250.24(C))

The grounding electrode conductor needs to connect to the neutral at the service disconnecting means in each panel. If you run only three wires, you're relying on the neutral conductor to also serve as the equipment grounding conductor (EGC). While this was allowed in older versions of the NEC for ranges, dryers, and subpanels under specific grandfathered circumstances in very old installations, it is NOT permissible for new services.2.

Separation of Neutral and Ground (250.24(A)(5))

The neutral (identified conductor) must be insulated, and it cannot be used for grounding on the load side of the service disconnect. The EGC has to be kept isolated from the grounded neutral conductor at any point downstream of the first disconnecting means.3.

Safety

Relying on the neutral for grounding introduces a potentially hazardous situation. If the neutral conductor is compromised, any metal parts connected to it could become energized.

Why Grouping is Required (and Hard to Avoid)230.72 mandates grouping the service disconnects (your 200A main breakers). The intent is to have a readily accessible and identifiable location where the entire service can be disconnected quickly and easily.

Let's analyze the NEC sections you mentioned and the potential for exceptions



230.71 (Maximum Number of Disconnects)

You're using the allowance for two to six disconnects. You have two. So, you're compliant on the number of disconnects.

230.72 (Grouping of Disconnects)

This is your problem. The general rule requires grouping.

The Exception is what we need to examine carefully. As you stated in the question, the Exception and subsection (B) does not apply. The NEC intentionally makes it difficult to avoid the grouping requirement, as the goal is to be able to quickly and easily de-energize ALL service conductors to a building by opening all of the grouped service disconnects. 230.70(A)(1) Location - Readily Accessible

This addresses where the disconnects need to be located. You're stating that your current panel locations are readily accessible. However, just being readily accessible doesn't excuse you from the grouping requirement.

Potential Scenarios (Highly Unlikely to Work, but Worth Considering)

Here are some ideas, but they are VERY unlikely to be compliant and would require VERY specific circumstances and AHJ approval.1. Very Close Proximity and Clear Labeling (Extremely Difficult)

If the panels are literally side-by-side on the same wall immediately after the point of penetration, and are considered by the AHJ to be effectively grouped, that could potentially work. However, this is highly unlikely. They'd need to be so close that they functionally appear as one assembly. And the neutral and EGC would need to be bonded in the meter socket to allow a 3-wire feed to each panel.2.

"Single Service" Argument (Unlikely)

You could try to argue that, because you're using a single 400A meter socket with double lugs, the two panels are essentially part of a single, larger service. This is a very weak argument, as you have two separate panels with main breakers. Even if the panels were immediately next to each other and connected using listed short nipples with appropriately sized bonding jumpers, this would be a difficult argument with the AHJ.

In Summary You must have a 4-wire feed (two hots, a neutral, and an equipment grounding conductor) to each panel, originating at the meter disconnect in this scenario. This is primarily due to grounding requirements (250.24(C), 250.32). You are almost certainly required to group your service disconnects per 230.72.

Recommendation1. Consult with the Authority Having Jurisdiction (AHJ)

Before doing anything, talk to your local electrical inspector. They have the final say on what's compliant in your area. Explain your scenario and ask what they would consider acceptable. Get it in writing if possible.2.

Consider a Different Design: If grouping is a major issue, you might consider a different design. For example, could you use a single, larger panelboard with a 400A main breaker right next to the meter socket and then feed the 200A loads from that panel? This would consolidate the service disconnect into a single point.In almost all practical scenarios, the NEC will require a 4-wire feed and grouped disconnects. There's very little room for interpretation here. Getting early feedback from the AHJ is critical. Flag for review