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MWBC installation playbook

Goal​

Install a multiwire branch circuit safely with correct phasing, neutral continuity, and disconnecting means.

Inputs you must know before you start​

  • Panelboard type and available breaker options.
  • Circuit layout and shared neutral routing.
  • Device locations and neutral connection requirements.
  • Required identification and labeling practices.

The path (in order)​

  1. Confirm opposite-phase ungrounded conductors for shared neutral.
  2. Select a common disconnecting means or handle-tied breakers.
  3. Maintain neutral continuity through devices and splices.
  4. Identify shared neutrals and multiwire circuits at the panel.
  5. Test circuit operation and document labeling.

This is​

A repeatable MWBC installation checklist that avoids open-neutral hazards.

This is not​

A full load balancing or harmonic analysis guide.

Inspection-ready checklist​

  • Common disconnecting means installed.
  • Neutral continuity maintained at all devices.
  • Conductors identified and labeled.
  • Circuit operation verified.

Worked example​

An MWBC serves two kitchen circuits with a shared neutral. The installer uses a common disconnect, keeps neutral continuity at devices, and labels the circuit at the panel.

Cross references​

  • Primary: 210.4
  • Secondary: 300.13, 210.7, 240

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