What the code actually requires
NEC 408.4 requires every circuit and circuit modification to be legibly identified as to its clear, evident and specific purpose, with enough detail that each circuit can be distinguished from all others. Spare positions containing unused overcurrent devices must be described as spare. That is the whole requirement: identity and honesty. No layout is prescribed.
IEC practice is similar in intent, different in vocabulary. IEC 60364-5-53 covers selection of switchgear, IEC 61439-1/-2 covers the assembly, and IEC 60364-6 covers verification and handover. In IEC projects the schedule usually sits inside a distribution board schedule set with the single-line diagram and test results.
So a schedule has three jobs, in this order: identify every way out of the panel (including spares and future ways), quantify what each carries in VA, amps, breaker rating and conductor size, and prove the panel is neither overloaded nor badly balanced. A template that does not do all three is a label list, not a schedule.
The 12 columns that earn their space
Most templates carry 20+ columns because a form once had them. These twelve cover design, installation, and the person with the flashlight.
| # | Column | Example entry | Why it stays |
|---|---|---|---|
| 1 | Circuit / way | 14 | Anchor for every other document |
| 2 | Description | Kitchen counter, south wall | Specific purpose, per NEC 408.4 |
| 3 | Phase / pole | L2, 1-pole | Balance and panel wiring |
| 4 | Breaker rating | 20 A | Must match conductor ampacity |
| 5 | Breaker type | 1-pole, AFCI | GFCI/AFCI/RCD requirement lives here |
| 6 | Conductor | 12 AWG Cu, 2-wire + ground | Size, material, count |
| 7 | Conduit / cable | 3/4 in EMT | Installation reference for the crew |
| 8 | Connected load, VA | 1,500 | Summable, unlike loosely used "watts" |
| 9 | Demand load, VA | 1,500 | After demand factors, for the total |
| 10 | Current, A | 12.5 | Connected VA divided by voltage |
| 11 | Voltage | 120 | Line-to-neutral vs line-to-line |
| 12 | Remarks | Spare, future, existing | State of the way, at a glance |
Two optional columns earn their ink on commercial work: earth-fault loop / disconnection time (IEC projects, where automatic disconnection must be proven) and lockout or arc-flash reference. Everything else — install date, electrician initials — belongs on the panel directory sticker.
Copy-paste template
Plain text, tab-separated, pastes cleanly into Excel, Sheets or a markdown table:
text
PANEL: LP-1 | 120/240 V, 1-ph, 3-wire | fed from MSB, 100 A | 125 A bus, 24 sp
Ckt | Description | Ph | Breaker | Type | Conductor | VA | Amps | Remarks
1 | Kitchen counter, south | L1 | 20 A | 1p AFCI | 12 AWG Cu | 1500 | 12.5 | GFCI
2 | Kitchen counter, north | L2 | 20 A | 1p AFCI | 12 AWG Cu | 1500 | 12.5 | GFCI
SPARES: 21-24 reserved, no breaker installed
The header block matters: a schedule without a rating, a source and a location is not traceable.
Worked example: a 12-circuit apartment panel
Single-phase 120/240 V. Line-to-neutral loads sit on one leg; line-to-line loads span both and split evenly.
| Ckt | Description | VA | Breaker / conductor | Leg |
|---|---|---|---|---|
| 1 | Kitchen counter, south | 1,500 | 20 A / 12 AWG | L1 |
| 2 | Kitchen counter, north | 1,500 | 20 A / 12 AWG | L2 |
| 3 | Dishwasher | 1,200 | 20 A / 12 AWG | L1 |
| 4 | Microwave | 1,500 | 20 A / 12 AWG | L2 |
| 5 | Laundry receptacles | 1,500 | 20 A / 12 AWG | L1 |
| 6 | Bath receptacles, GFCI | 1,000 | 20 A / 12 AWG | L2 |
| 7 | Bedrooms | 1,200 | 15 A / 14 AWG | L1 |
| 8 | Living room | 1,000 | 15 A / 14 AWG | L2 |
| 9 | Lighting | 900 | 15 A / 14 AWG | L1 |
| 10 | Dryer | 5,500 | 30 A / 10 AWG | L1-L2 |
| 11 | Range | 8,000 | 40 A / 8 AWG | L1-L2 |
| 12 | A/C condenser | 4,800 | 25 A / 10 AWG | L1-L2 |
Line-to-neutral: L1 = 1,500 + 1,200 + 1,500 + 1,200 + 900 = 6,300 VA; L2 = 1,500 + 1,500 + 1,000 + 1,000 = 5,000 VA.
Line-to-line: 5,500 + 8,000 + 4,800 = 18,300 VA, or 18,300 / 2 = 9,150 VA per leg.
Per-leg totals: L1 = 6,300 + 9,150 = 15,450 VA; L2 = 5,000 + 9,150 = 14,150 VA. Imbalance = 1,300 VA = 1,300 / 15,450 = 8.4% of the heavier leg. Under 10%, the usual comfort threshold — a practice target, not a code limit.
To improve it, move load from the heavier leg to the lighter one and move less than the gap. Circuit 9 (900 VA) from L1 to L2 gives 14,550 and 15,050 VA — 500 VA apart, 500 / 15,050 = 3.3%. Overshooting is easy: shift circuit 5 (1,500 VA) from L1 to L2 instead and the legs land at 13,950 and 15,650 VA, a 10.9% imbalance that has merely swapped sides. Keep the base of the percentage fixed (the heavier leg) or the numbers stop being comparable.
Connected total: 6,300 + 5,000 + 18,300 = 29,600 VA, which at 240 V is 29,600 / 240 = 123.3 A before any demand factor. After NEC 220 demand factors — the range drops to 8,000 VA under Table 220.55, general lighting takes the first 3,000 VA at 100% and the rest at 35% — the calculated load is materially lower. Do the demand calculation separately; never size a service from the connected column.
For the same circuit list checked against ampacity and volt drop, see the voltage drop calculator walkthrough.
Where templates break
- Spares that are not spare. A breaker was added on site, the schedule was never updated, and position 21 is now a live 20 A circuit labelled "Spare". NEC 408.4 exists because of this.
- Room names instead of circuit descriptions. "Living room" is useless when the room has four circuits. "Living room receptacles, north wall" is not.
- Duplicate circuit numbers across revisions. Two people edit the sheet and both add "13".
- Schedule and single-line diagram disagree. The single-line diagram shows 18 ways, the schedule lists 20. One is wrong and nobody knows which.
From template to automated schedule
A spreadsheet is fine for one panel. It stops being fine when the panel changes three times and the schedule must change with it, because every edit is manual and can break the link between drawing and document.
Automation means the schedule is a view of design data: the circuit list comes from the single-line diagram, so adding a way adds a row; breaker and conductor fields are checked against ampacity and derating; phase assignment is computed and imbalance reported as you go; spares are a state, so an unused position cannot silently become live; and the PDF carries the same revision as the drawing set. That is what panel schedule software is for — the difference between a template that documents a design and one that argues with it.
Want to see the generated version of the template above? Open the demo project — it loads with a plan, a small panel and a schedule you can edit.
Next step
The template is free to copy. If you would rather have the schedule generated from the plan and the single-line diagram — with breaker, cable and balance checks running as you edit — start with the demo, then compare plans on the pricing page. Product limits and export options are in the docs.
Sources
- NFPA 70 (NEC) — code development and current edition: https://www.nfpa.org/codes-and-standards/nfpa-70-standard-development/70
- NFPA free access to codes and standards: https://www.nfpa.org/codes-and-standards/free-access
- IEC 60364-5-52:2009 — wiring systems, current-carrying capacity: https://webstore.iec.ch/en/publication/1878
- IEC 60364-5-53:2001 — selection and erection of switchgear: https://webstore.iec.ch/en/publication/1880
- Southwire voltage drop calculator (reference implementation): https://www.southwire.com/calculator-vdrop
Standards are revised on a regular cycle and local amendments vary. Verify requirements against the current edition of the applicable code before issuing a design. This article is technical guidance, not a legal or code-compliance opinion.
No. NEC 408.4 requires legible identification of each circuit's specific purpose and identification of spares, but prescribes no layout. Local jurisdictions and client standards often do. Check the current edition and local amendments.
Yes. An installed but unused breaker is a spare; an empty position with no breaker is a space. Both should appear, labelled differently, because the next person needs to know whether to buy a breaker.
Common practice is 20–25% spare ways and 20–30% spare bus capacity — a design convention, not an NEC requirement. Some client standards mandate more.
There is no universal code number. A widely used design target is within 10% between legs at the connected-load stage. Motors and large single-phase loads are what usually break it.
For one small panel, yes. The risk is divergence: schedule and drawing are separate files with separate revisions, and nobody reconciles them.
Add A/B/C phase columns, show line-to-line loads as spanning two phases, and total each phase separately. The arithmetic is identical; the imbalance check is between three numbers.
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