How long does it take to panel replacement & load re-balance?

This task typically takes 6–12 hours to complete, depending on your experience level and the specific conditions of your electrical plumbing system.

What tools do I need to panel replacement & load re-balance?

You'll need the following tools: Insulated lineman pliers, Torque screwdriver, Voltage tester (CAT III). Make sure all tools are in good condition before starting.

Is this task suitable for beginners?

This task is rated as Professional difficulty. This task requires professional expertise and should only be attempted by licensed plumbers.

All guides

ElectricalAdvanced

Panel Replacement & Load Re-Balance

Time

360–720 min

Steps

Pre-check

10 items

Skill

Advanced

Scope

Replace a residential service panel — typically swapping a legacy panel (FPE Stab-Lok, Zinsco, or end-of-life 60 A fuse) for a current code-compliant 100 A or 200 A panel, and re-balance branch circuits across the two hot legs.

Safety

Read before starting

The line side of a residential panel is energized by the utility — you cannot de-energize it from inside the house. This work REQUIRES a utility cutoff (meter pull or service disconnect). Most jurisdictions also require this be done by a licensed electrician under permit. This guide exists as preparation reference for homeowners coordinating with their electrician, NOT as a DIY procedure.

Pre-Check

10 items · complete before you start

Confirm circuit identification at the panel — note breaker number and amp rating
Required
Trace the circuit before you cut power so you know which breaker to lock. Mis-identification is the single most common cause of "I thought it was off" incidents.
Non-contact voltage tester proven against a known-live source IMMEDIATELY before use
Required
Test the tester on a live receptacle in the same room. UL-rated testers can fail silently — proving it on a known source is the only way to trust a zero reading.
Lockout-tagout device for the breaker if anyone else could re-energize it
Required
A breaker lock is ~$8. If you are home alone with the only key, a printed tag on the panel is the minimum.
Insulated tools (1000 V rated screwdrivers and pliers)
Required
Standard hardware-store handles are not insulated for live-electrical work.
Safety glasses and dry, insulating footwear
Required
Concrete/wet floors are a parallel path to ground. Stand on a dry rubber mat if the floor is questionable.
Working flashlight or headlamp independent of room lighting
Required
When the breaker goes off, room lights on the same circuit go with it.
Licensed electrician engaged and permit pulled
Required
Panel replacement is licensed work in essentially every US jurisdiction. The permit drives the inspection that verifies grounding, bonding, and load calc.
Utility scheduled for meter pull or service disconnect
Required
The utility-side conductors at the meter and the line side of the main remain energized after the homeowner main breaker is off. Only the utility can de-energize them.
Load calculation completed per NEC §220
Required
Drives the choice between 100 A and 200 A panel. Future loads (EV charger, heat pump, induction range) push toward 200 A or 320/400 A service.
Existing circuit inventory documented
Required
Photograph the existing panel directory and trace any unlabeled breakers BEFORE the swap.

0 / 44 complete

Plan the swap and re-balance

Inventory every existing branch circuit: amp rating, conductor size, room/load served
Note any AFCI / GFCI requirements triggered by NEC 2023 §210.8 and §210.12 for the new panel
Plan circuit placement to balance load across the two 120 V legs — sum amperage on Leg A ≈ sum amperage on Leg B
Put pairs of related loads on opposite legs (e.g. kitchen + bath both heavy on each leg)
Identify any multi-wire branch circuits (MWBC) — must land on a 2-pole or handle-tied breaker per NEC §210.4(B)

Code notes

NEC §408.40 — equipment grounding bus in panelboards.
NEC §230.67 — surge protective device required at dwelling-unit service equipment (NEC 2023).

Utility cutoff — coordinate with the utility

The utility pulls the meter or opens the service disconnect — this is the only way to de-energize the line side
A licensed electrician witnesses the cutoff and verifies zero energy at the line lugs
Lockout/tagout is applied per utility protocol; bypass is utility-prosecution territory
Confirm the utility tag and seal — DO NOT cut a utility seal yourself

⚠ Warnings

Cutting a utility seal is a criminal offense and can result in disconnection plus prosecution.
Working hot on the line side has killed experienced electricians. There is no shortcut.

✅Continue Gate:Have you (1) turned off the breaker, (2) tested your non-contact tester on a KNOWN-LIVE source, (3) verified zero energy at the conductors you are about to touch, and (4) re-tested the tester on the known-live source to confirm it still works? (NFPA 70E §120.5)

Document and remove existing circuits

With the panel de-energized and verified, photograph every wire connection
Label each branch conductor with its destination (use printed tape, not Sharpie that wipes off)
Disconnect each branch one at a time, working from top to bottom
Disconnect the neutral bus and ground bus connections, labeling as you go
Disconnect the main service conductors (line side) — the utility witness verifies these are dead

Remove the old panel; mount the new

Remove the old enclosure — note the existing knockouts and conduit entries
Mount the new panel: same location is simplest; relocation requires re-routing all conductors
Re-use existing conduit and weatherhead where possible
Bond the new enclosure to the grounding electrode system per NEC §250.50 — water pipe + ground rod(s) + Ufer if available
Install service-entrance surge protection per NEC §230.67 (required as of NEC 2023)

Code notes

NEC §250.50 — bonding all available grounding electrodes (water pipe ≥10 ft contact, ground rods 8 ft × 2, Ufer / concrete-encased electrode).
NEC §250.104(A) — bond metallic water piping to the service equipment ground.
NEC §110.26(A) — working clearance: 36 in depth, 30 in width, 6 ft 6 in height in front of the panel.

Land branch circuits with re-balance

Land each branch hot on the breaker space that balances total load across Legs A and B
Multi-wire branch circuits land on a 2-pole or handle-tied 2-single-pole breaker (NEC §210.4(B))
Each grounded (neutral) conductor lands on an individual neutral bus terminal — no doubling (NEC §408.41)
Each equipment grounding conductor lands on the ground bus — most panel manufacturers allow two grounds per terminal; verify the panel label
AFCI and GFCI requirements per NEC 2023 §210.8 and §210.12 — install AFCI/GFCI breakers as required for each circuit
Torque every lug to the panel's spec sticker

Service Panel Layout (Main & Buses)· NEC Wiring

⚠ Warnings

Aluminum branch-circuit conductors (mid-1960s to mid-1970s "old technology aluminum") require Co/Alr-rated devices and anti-oxidation compound. If you find aluminum branch wiring, scope expands — discuss with your electrician.

Restore service and verify

Reinstall the deadfront cover
Utility re-installs the meter and re-energizes
Set the main breaker, then restore each branch one at a time
Verify 240 V between hot legs at the bus; verify 120 V each leg to neutral
Walk every circuit: test each receptacle, switch, and appliance for normal operation
Verify AFCI / GFCI test buttons trip and reset on every required circuit

Inspection sign-off

Leave the deadfront OFF for the AHJ inspector — they verify torque, conductor sizing, grounding/bonding, and clearance
Have the load calc, panel directory, and any SCCR labeling visible
Document the final-passed inspection — required for some insurance carriers

Scope

Safety

Pre-Check

Steps

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