Solar Wire & Cable: Gauge Guides, Calculators & NEC Resources
Undersized wire is the most common DIY solar failure — and the easiest to avoid. Voltage drop eats production, wrong insulation types fail inspection, and ampacity mistakes are fire hazards. This hub consolidates our complete wire and cable library: per-gauge ampacity guides from 22 AWG signal wire to 4/0 battery cable, NEC-based sizing calculators, PV wire and grounding guides, and the catalog itself. Bookmark the amp chart, run your runs through the voltage drop calculator, and pull the gauge guide for whatever you're installing.
Wire Gauge Guides (AWG)
Ampacity, uses, and specs for every common gauge — NEC-referenced.
Signal and low-voltage control runs — ampacity and common solar uses.
15A circuits, lighting, and small loads.
20A branch circuits — the residential workhorse.
30A circuits: water heaters, small solar strings, RV feeds.
40A runs — EV chargers, subpanels, larger PV strings.
55A service for big inverters and 50A EV circuits.
70A feeders for subpanels and mid-size battery banks.
95A runs — large inverter DC links and service feeders.
125A class for battery banks and heavy DC runs.
150A feeders and large off-grid battery interconnects.
200A service entrance and serious inverter battery cables.
The full ampacity table across all gauges — the quick reference.
Sizing Tools & Calculators
NEC-based tools — size it right the first time.
DC & AC runs — check drop percentage before you pull wire.
NEC 310.16-based sizing with derating for conduit fill and temperature.
PV string and battery cable sizing for solar systems.
The NEC 125% continuous-load rule matched to wire gauge.
Solar & NEC Guides
PV wire types, grounding, and code compliance for solar work.
String sizing, 156% rules, and temperature correction for PV circuits.
NEC 250/690.43 grounding for solar and battery systems.
The wire types we stock and where each belongs.
Shop Wire & Cable
Cut-to-length and full spools, contractor pricing on volume.
THHN, PV wire, USE-2, and specialty cable.
UL 4703 sunlight-resistant solar array wiring.
Building wire for conduit runs, services, and feeders.
Lugs, connectors, heat shrink, and cable management.
Latest Guides & Comparisons
Newest long-form articles in this topic, straight from the blog.
- How to Size Circuit Breakers: NEC 125% Rule (2026)Aug 12, 2026
- NEC Wire Sizing Guide: Ampacity Charts for Solar & GeneratorsJul 31, 2026
- Electrical Conduit Types: PVC vs EMT vs RMC for SolarJul 31, 2026
- MC4 Connectors & Solar Wire Gauge GuideJul 22, 2026
- Conduit Fill Chart: Max THHN Conductors per EMT SizeJul 22, 2026
- Wire Ampacity Chart (NEC 310.16): Copper & AluminumJul 22, 2026
- Solar Grounding & Bonding: NEC 690.43, 250May 15, 2026
- Solar Wire & Cable Guide: PV Wire vs USE-2 vs THHNMar 15, 2026
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