The ranking is rules, not opinion — here is exactly how an answer set becomes a ranked result and a safe next check.
source-governedDiagnostic estimate. Not a quote, not a substitute for a licensed electrician.source pack dated 2026-09-13 · authority hashes pendingview sources ↓
Method
Voltage drop is computed as round-trip 2 × length × current × resistance-per-foot, then expressed as a percent of 120 V; the numbers and the rule appear in the trace.
Two independent checks run: load against a conservative per-gauge current ceiling and voltage drop against the configured 3% / 5% bands. The more conservative condition controls the result.
The calculation does not override product-specific instructions. The cited Honeywell HCE210/HCE220 heater manual, for example, requires direct wall connection and prohibits extension cords for those models.
Sources
manufacturer Southwire SPEC 45042 — Class K flexible stranded copper resistance engineering data · source pack dated 2026-09-13 · authority hashes pending
reference NIST Building Science Series 128 — branch-circuit voltage-drop relationship and 3% / 5% guidance · source pack dated 2026-09-13 · authority hashes pending
Where to stop. Choosing or replacing an extension cord is homeowner-safe. If the load is a portable space heater, follow the heater's manufacturer instructions; the cited Honeywell HCE210/HCE220 manual requires plugging directly into a wall receptacle and not using an extension cord. Anything involving the building's wiring or circuit rating is a licensed electrician's job. This is general information, not a quote and not a substitute for a licensed electrician.
Electrical Fault Check provides general diagnostic information only. It is not professional advice, not a quote, and not a substitute for a licensed electrician. Do not work on live wiring. If you see smoke, sparks, burning smell, heat, shock, water exposure, or repeated tripping, stop using the circuit and contact a licensed electrician or emergency services as appropriate.