Installation Guides
Subpanel Planning Guide
Feeder, neutral isolation, grounding, access, labeling, and verification.
Treat a subpanel as feeder-supplied equipment: plan capacity, conductor system, neutral isolation, grounding, working space, and future serviceability together.
Planning
- Calculate feeder load and confirm upstream capacity.
- Choose location for access, working space, environment, and short conductor routing.
- Confirm available fault current and panel rating.
Key decisions
- Feeder conductor count and wiring method.
- Neutral isolation from the enclosure and equipment-grounding bar.
- Grounding-electrode requirements for a separate structure.
Installation
- Keep grounded and grounding conductors on their intended bars.
- Use listed fittings and correct connector count.
- Torque, phase, balance, and label circuits deliberately.
Commissioning & pitfalls
- Verify neutral-to-enclosure isolation, grounding continuity, feeder voltage, labeling, and directory accuracy.
- Common failures: bonded neutral downstream, missing fourth conductor, shared neutrals handled incorrectly, and weak working space.