You've hit on a common point of confusion regarding the "six disconnect rule" and subpanels, particularly when feeding a second structure. Let's break it down

Understanding NEC 225.31 and the Six Disconnect Rule
NEC 225.31 (Means of Disconnect)

This section requires a disconnecting means for the feeder at the second structure (the one being fed from the first).

NEC 225.33 (Maximum Number of Disconnects)

This is where the "six disconnect rule" comes in. It allows a maximum of six switches or six circuit breakers to serve as the disconnecting means at each structure. This is intended for ease of operation in an emergency. The important part is that this rule applies to the MAIN disconnects, not branch circuits.

Addressing Your Questions and Concerns1. The wording "six circuit breakers mounted in a single enclosure" in relation to subpanels

You're absolutely correct. The NEC isn't counting branch circuit breakers when it states "six circuit breakers mounted in a single enclosure." This refers to the

main disconnecting means. The intent is that you shouldn't have to hunt through a bunch of panels to kill power to the building.2. "Can be fed by no more than one feeder and must terminate into a single enclosure with no more than 6 breakers"

This is often misinterpreted. The feeder coming from the first house MUST terminate into a single enclosure. That enclosure can contain one large main breaker (serving as the disconnect) or up to six smaller breakers, all of which collectively disconnect the entire feeder. The single enclosure is where the feeder terminates, but the number of branch circuits within that enclosure is not restricted to six.3.

Does the main subpanel breaker serve as the supply disconnect? Yes, if it meets the following conditions: It disconnects ALL ungrounded conductors

The breaker must interrupt all hot (ungrounded) conductors of the feeder.

It is readily accessible

It must be easy to reach in case of emergency.

It is permanently marked

It must be clearly labeled as the "Main Disconnect" or "Building Disconnect" or similar. NEC 225.36 and 225.37 cover these marking requirements.

It's suitable for use as service equipment

The panelboard must be listed and labeled for use as service equipment.

In summary

A separate "pull switch" is not required if the main breaker in the subpanel meets the above criteria. However, some electricians might prefer a separate disconnect for added safety and clarity.

Example Scenario

Let's say you run a feeder to the second house and install a 100A subpanel there. Acceptable (Main Breaker as Disconnect)

A 100A main breaker in the subpanel serves as the disconnect, as long as it's properly labeled, accessible, and the panel is rated as service equipment. You can then have as many branch circuits (more than six) as needed within that subpanel.

Acceptable (Multiple Breakers as Disconnect)

You could also use a subpanel where up to six breakers add up to providing the necessary current interruption to the feed from the first building. This setup is rarely used in residential applications.

Important Considerations Overcurrent Protection

The feeder to the second structure must be properly sized and protected with an overcurrent device (breaker or fuses) at the point of origin (first house).

Grounding

The grounding system at the second structure must be properly installed, including a grounding electrode system (ground rod, etc.). This is critical for safety.

Bonding

All metal parts of the electrical system at the second structure must be properly bonded to the grounding electrode system.

Local Codes

Always check with your local electrical inspector, as they may have additional requirements or interpretations of the NEC.

Why the Confusion?

The wording in the NEC can be ambiguous, and the "six disconnect rule" is one of the most frequently misunderstood concepts. The key takeaway is that the rule applies to the main disconnecting means for the feeder, not the individual branch circuits within the subpanel. The NEC wants to ensure that someone can quickly and easily shut off power to a building in case of an emergency. Flag for review