Install a Small Residential Subpanel Feeder and Panel Interior

A. Finished-Project Specification

Quantity: one mounted subpanel cabinet, one terminated feeder, one isolated neutral bar verified separate from the cabinet, one equipment-grounding bar bonded to the cabinet, branch breakers installed according to the approved panel schedule, filler plates and deadfront installed, and one completed Subpanel Readiness Worksheet, all completed under the authority defined in the Setup Standard.

B. Subpanel Readiness Schedule

Item	Target Condition	Verification Method
Approved design confirmation	Load calculation, feeder design, panel schedule, and fault-current information confirmed before mounting	Written record on worksheet
Fully de-energized condition	All identified energy sources controlled and absence of voltage verified at every bus and terminal location	Direct test and qualified-person confirmation
Cabinet mounting	Cabinet plumb, level, and secured to required structural backing	Level check and fastener inspection
Feeder routing and termination	Feeder routed without exceeding bend, support, or fill limits and terminated to manufacturer torque	Visual inspection and torque record
Neutral isolation	Neutral bar verified electrically isolated from the cabinet before termination	De-energized continuity test
Grounding bond	Equipment-grounding bar bonded to the cabinet using listed hardware	Visual inspection and continuity test
Branch breaker installation	Listed compatible breakers installed in scheduled positions with conductors terminated per schedule	Visual inspection against panel schedule

C. Material Takeoff

• Panel assembly: one listed subpanel cabinet, isolated neutral bar, and equipment-grounding bar matching the confirmed manufacturer, model, bus rating, and breaker family.
• Feeder materials: feeder conductors, raceway or cable, and connectors matching the approved feeder design, plus required supports and protection.
• Branch materials: listed branch breakers matching the approved panel schedule, plus filler plates for unused positions.
• Mounting materials: structural backing and fasteners suitable for the selected location.
• Documentation: one Subpanel Readiness Worksheet, plus photographs of the mounted cabinet, feeder terminations, isolated neutral bar, and bonded grounding bar.

D. Acceptance Standards

Check	Standard
Location and mounting	Cabinet plumb, level, and secured with required working space, headroom, and structural support
Feeder termination	Feeder conductors terminated at manufacturer-specified torque with no damaged strands or reduced free length
Neutral isolation	Isolated neutral bar shows no continuity to the cabinet before any neutral conductor is landed
Grounding bond	Equipment-grounding bar shows continuity to the cabinet using listed bonding hardware
Branch terminations	Every branch breaker and conductor matches the approved panel schedule with correct torque
Neutral-to-ground bonding	No neutral-to-ground bonding point exists anywhere in this subpanel
Documentation	Subpanel Readiness Worksheet complete with feeder design, torque, isolation-test, and inspection-approval entries

E. Design Confirmation and Location Planning

1. Obtain the approved load calculation, feeder design, panel schedule, fault-current information, grounding design, permit, and inspection requirements. Confirm all values in writing before proceeding.
2. Confirm the subpanel manufacturer, model, bus rating, breaker family, main-lug or main-breaker configuration, enclosure rating, and installation environment. Reject any cabinet or component that does not match the approved design.
3. Verify the approved feeder conductor material, size, insulation, raceway or cable, equipment-grounding conductor, overcurrent protection, and neutral requirement. Record each value on the worksheet.
4. Select a location providing required working space, headroom, accessibility, structural support, environmental protection, and cable routes. Do not select a location that fails any of these requirements.

F. Establishing a Fully De-Energized Condition

1. Identify all power sources and establish a fully de-energized work condition. Include the utility service, generators, photovoltaic systems, batteries, and any backfed equipment.
2. Stop work if the upstream equipment or feeder termination point cannot be made electrically safe. Escalate to the qualified electrical professional before proceeding.

G. Cabinet Mounting

1. Mark the panel height, centerline, fastener points, and finished-wall relationship. Use the location confirmed in Section E.
2. Install structural backing or listed supports where required. Confirm the backing engages the required framing.
3. Mount the cabinet plumb, level, and securely using approved fasteners. Verify with a level before final tightening.

H. Feeder and Branch Raceway Preparation

1. Install listed feeder and branch-circuit raceway or cable connectors. Match each connector to its listed cable, raceway, and enclosure condition.
2. Close all unused openings with listed closures. Leave no open knockout or unused entry.
3. Route the approved feeder to the cabinet without exceeding bend, support, fill, or pulling requirements. Confirm the route matches the approved design.
4. Protect feeder conductors from abrasion and physical damage. Install protection at any location where the feeder could contact a sharp edge or moving component.

I. Isolated Neutral and Bonded Grounding Bar Installation

1. Prepare feeder conductors to the manufacturer's strip lengths. Avoid nicking or reducing conductor strands.
2. Install the isolated neutral bar without the bonding screw or strap that would bond it to the cabinet. Confirm the factory shipping hardware, if bonded, has been removed or set to the isolated configuration.
3. Install the equipment-grounding bar bonded to the cabinet using listed hardware. Confirm the bonding hardware is fully seated.
4. Verify electrical isolation between the neutral bar and cabinet before termination. Perform a de-energized continuity test and confirm no continuity exists.

J. Feeder Termination

1. Terminate the feeder equipment-grounding conductor at the grounding bar. Use the listed terminal and torque method.
2. Terminate the feeder grounded neutral conductor at the isolated neutral terminal. Confirm the neutral terminal is on the isolated bar, not the grounding bar.
3. Terminate feeder ungrounded conductors at the approved main lugs or breaker. Match each conductor to its designated terminal.
4. Tighten all feeder terminals to manufacturer-specified torque using a calibrated method. Record each torque value on the worksheet.

K. Branch Circuit Termination

1. Route and terminate branch-circuit neutrals individually as required. Confirm each neutral lands on the isolated neutral bar in its own listed terminal position.
2. Route and terminate equipment-grounding conductors at the grounding bar. Confirm each grounding conductor lands on the bonded grounding bar.
3. Install only listed compatible branch breakers in the scheduled positions. Reject any breaker not listed as compatible with the panel bus.
4. Terminate branch ungrounded conductors at their assigned breakers. Match each conductor to the position specified in the approved panel schedule.
5. Maintain conductor identification, bending space, and panel order. Dress conductors so the schedule can be verified visually.

L. Closeout, Verification, and Authorized Energization

1. Install filler plates, deadfront, labels, and circuit directory. Leave no open breaker position uncovered.
2. Perform de-energized continuity and isolation checks. Confirm every branch neutral, grounding conductor, and feeder termination matches the approved schedule.
3. Verify that neutral-to-ground bonding does not exist in the subpanel. Confirm this with a direct continuity test between the isolated neutral bar and the cabinet.
4. Obtain required inspection before energization. Do not proceed to energization without this approval.
5. Energize only under the authority and procedure of the qualified electrical professional. The learner does not independently energize this subpanel.
6. Perform approved voltage, breaker, grounding, and operational checks. Complete these checks with or under the direction of the qualified electrical professional.
7. Document feeder design, conductor materials, breaker models, torque values, isolation tests, and inspection approval. Complete every field on the Subpanel Readiness Worksheet.