What this is
WireAndAmpChart is a free, browser-based electrical reference with two doors. The Quick Project Finder answers the homeowner question (which wire, which breaker, which conduit for an EV charger, a dryer, a hot tub, a subpanel or a well pump, at your distance) in one plain line. The 1:1 screen gauge and pro inputs carry the rest: a true-size wire caliper, stripper comb and coil ruler, NEC Table 310.16 ampacity with derating, conduit and box fill, voltage drop and speaker wire.
Measuring on the screen
A browser does not know the physical size of its pixels, so the gauge starts from a table of 114 phones, tablets, laptops and monitors matched to your screen and asks you to confirm it with a coin or a bank card laid on the glass. The caliper lines run edge to edge with every number in a protected strip, so the fingers holding a wire never cover them, and a white backlight shows a dark wire as a silhouette. Below about 24 AWG a pixel is too coarse; the coil ruler measures ten turns instead.
Where the numbers come from
- NEC 2023 Table 310.16 ampacity, Table 310.15 corrections, 240.4, 250.122, 250.66, 314.16, 400.5 and 430.248, from public reproductions (Elliott Electric, Cerrowire, Southwire, the Steel City catalog), cross-checked against each other.
- NEC Chapter 9 Tables 1, 4, 5 and 8 for conduit fill, insulated diameters, stranding and resistance; the fill engine reproduces Annex C.
- The AWG formula (ASTM B258) for solid diameters, IEC 60228 metric sizes, the British SWG, Southwire NM-B and DLO data sheets, ERI and Carlon conduit diameters, ABYC E-11 for boats and ASTM B566 for copper-clad aluminum.
Each spec sheet has a Notes & Sources tab with the links, and the site’s source log lists the date each table was retrieved.
What it is not
It is not an inspection or a design. Your jurisdiction adopts a code edition, sometimes with amendments, and the inspector (the authority having jurisdiction) decides what complies; the equipment’s own instructions can ask for more than the minimum shown here. Every “meets” badge says to verify locally.
Who runs it
WireAndAmpChart is an independent reference with no ties to any wire maker or retailer. If a number looks wrong, write to contact@wireandampchart.comwith the page and your inputs (the share link carries them all).