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Electricalaka: AWGaka: American Wire Gaugeaka: wire size

Wire Gauge

In Plain English

The standardized size rating for electrical wire — a lower number means a thicker wire that can carry more current.

Definition

A standardized measurement system for the diameter of electrical conductors, using the American Wire Gauge (AWG) scale where smaller numbers indicate larger wire diameters. Common residential gauges include 14 AWG (15A circuits), 12 AWG (20A circuits), and 10 AWG (30A circuits). Wire gauge must match the circuit's ampacity to prevent overheating.

Why It Matters in Bidding

Wire gauge is a primary cost driver in electrical takeoffs because copper is priced by weight and larger conductors cost dramatically more per foot, so feeder and branch-circuit gauges chosen during pricing move the bid materially. Specifying the wrong gauge risks a non-conforming installation, failed inspection, and rework, all of which erode an electrical sub's margin.

Example

An electrical estimator takes off 12 AWG for the 20-amp kitchen and laundry branch circuits but upsizes a long home-run to 10 AWG to offset voltage drop, pricing the heavier copper into that run.

Related Terms

ConductorAmpere (Amp)Circuit BreakerConduit

Frequently Asked Questions

Conductors are priced largely by copper weight, so each step to a larger gauge sharply increases material cost per foot. Long runs may need upsizing for voltage drop, adding cost beyond ampacity minimums. Accurate gauge takeoff per circuit, plus conduit fill implications, keeps the electrical bid competitive without underpricing the copper.
American Wire Gauge is an inverse scale rooted in historical drawing-die counts; the more times wire was drawn, the smaller it became and the higher its number. So 10 AWG is thicker and carries more current than 14 AWG. Estimators must read the scale correctly to avoid undersizing conductors during takeoff.
Yes. Code recommends limiting voltage drop on long runs, so a conductor sized for ampacity alone may still need upsizing on extended home-runs or feeders. Estimators should flag long circuits and price the larger gauge, since failing to account for voltage-drop upsizing causes underbidding and potential field rework.

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