Recommendation Applied by the app elec.voltage-drop.branch-limit
Voltage drop on a branch circuit
The app flags a branch circuit whose drop to the farthest device exceeds 3% — the NEC's informational recommendation, not a requirement.
| When | The app uses |
|---|---|
| branch circuit, to the farthest device | 3 % |
- Source
- NEC · 210.19(A), Informational Note · read the public text
- Editions checked
- 2017 · 2020 · 2023
- Used by
- Bid Check
- Amendments
No state or local amendment to this rule is on file. Not on file means the model code as written — check your jurisdiction.
In the code, but advisory — an informational note, not a requirement.
The Code does not require a maximum voltage drop on a branch circuit; it recommends one, in an Informational Note: conductors sized so the drop at the farthest outlet stays within 3% (and 5% for feeder plus branch together) will provide reasonable efficiency of operation. Some jurisdictions and the energy codes turn the recommendation into a requirement, and most specifications do.
What the app does with it
The Voltage drop within 3% to the farthest device row in Bid Check walks each circuit — a group with a panel and circuit number — along its runs to the device farthest from the panel, applies the load and voltage from the Bid Check defaults (or the group's own), and reports the drop with the gauge that would pass when it does not. The 3% is the default limit; the calculation itself uses the K constant on its own page.
What it does not do
It does not check the feeder side, and it does not know your specification's limit. If the spec says 2%, the row is only a first warning.
Cited by section, not reprinted: the code text belongs to its publisher. Company practice is not a rule here — it lives with your pricing.