Engineering model reference

CCA-to-Copper Diameter Comparison at Equal Calculated Current

Compare 6–30 AWG solid CCA wires at six copper mass fractions. Select bare wire or same-thickness PVC, then read the corresponding solid copper metal diameter. Equal-resistance results are kept separate.

RT-TEC-CAL-CCA-AWG-001 Rev.1 · Calculated 2026-10-07

Without JavaScript, all three complete tables and their conditions are available below. /* The shared layout loader otherwise covers content without JavaScript. */ body:has(.cca-equivalence) #page-loader { display: none !important; }

Bare wire: equal-current copper diameter

Single, long, straight horizontal wire suspended in open still air. Ambient and surrounding radiation temperature 35°C; conductor 85°C; CCA and copper emissivity both 0.4. DC steady state; no solar load, nearby heat sources, joints or end cooling.

Match the calculated steady-state current under these thermal conditions. This does not imply equal resistance, voltage drop or losses.

Values: equivalent solid copper METAL diameter in mm. Copper-content columns refer to CCA mass percentages.

On narrow screens, scroll the table horizontally. The table region is keyboard focusable.

Bare wire: equal-current copper diameter — metal diameter (mm); copper by mass
CCA AWG	CCA metal Ø (mm)	21% Cu by mass	30% Cu by mass	40% Cu by mass	50% Cu by mass	60% Cu by mass	70% Cu by mass
6	4.115	3.473	3.505	3.547	3.596	3.656	3.730
7	3.665	3.090	3.119	3.156	3.201	3.254	3.320
8	3.264	2.749	2.775	2.809	2.848	2.896	2.955
9	2.906	2.445	2.468	2.498	2.534	2.577	2.630
10	2.588	2.175	2.196	2.223	2.254	2.293	2.340
11	2.304	1.934	1.953	1.977	2.005	2.040	2.082
12	2.052	1.721	1.737	1.759	1.784	1.815	1.853
13	1.829	1.532	1.547	1.566	1.589	1.617	1.651
14	1.628	1.362	1.375	1.393	1.413	1.438	1.468
15	1.450	1.212	1.224	1.239	1.257	1.280	1.307
16	1.290	1.077	1.087	1.101	1.118	1.137	1.162
17	1.151	0.960	0.969	0.981	0.996	1.014	1.036
18	1.024	0.853	0.861	0.872	0.885	0.901	0.921
19	0.912	0.758	0.766	0.776	0.788	0.802	0.820
20	0.813	0.675	0.682	0.691	0.702	0.714	0.730
21	0.724	0.601	0.607	0.615	0.624	0.636	0.650
22	0.643	0.533	0.538	0.545	0.554	0.564	0.577
23	0.574	0.475	0.480	0.486	0.494	0.503	0.514
24	0.511	0.422	0.427	0.432	0.439	0.447	0.458
25	0.455	0.376	0.380	0.385	0.391	0.398	0.407
26	0.404	0.333	0.337	0.341	0.347	0.353	0.361
27	0.361	0.297	0.300	0.305	0.309	0.315	0.323
28	0.320	0.263	0.266	0.270	0.274	0.279	0.286
29	0.287	0.236	0.238	0.242	0.246	0.250	0.256
30	0.254	0.208	0.211	0.214	0.217	0.221	0.227

Rounding to 0.001 mm is for display only, not a tolerance, accuracy claim or safety margin. Equivalent diameters are usually not standard copper AWG sizes; do not substitute the nearest gauge without engineering verification.

Download this mode’s original CSV

Equal-current copper core with 0.6 mm PVC

Both conductors have 0.6 mm radial PVC insulation; thermal conductivity 0.20 W/(m·K), outer-surface emissivity 0.9. Ambient and surrounding radiation temperature 35°C; conductor 70°C. Single, long, straight horizontal wire in open still air; DC steady state, no solar load, nearby heat sources, joints or end cooling. This thickness is not claimed suitable for every AWG or voltage rating.

Compare copper metal-core diameters with the same radial insulation thickness. Insulation conduction and outer-surface temperature are part of this model; the values are not finished insulated diameters.

Values: equivalent solid copper METAL diameter in mm. Copper-content columns refer to CCA mass percentages.

On narrow screens, scroll the table horizontally. The table region is keyboard focusable.

Equal-current copper core with 0.6 mm PVC — metal diameter (mm); copper by mass
CCA AWG	CCA metal Ø (mm)	21% Cu by mass	30% Cu by mass	40% Cu by mass	50% Cu by mass	60% Cu by mass	70% Cu by mass
6	4.115	3.460	3.492	3.535	3.585	3.647	3.722
7	3.665	3.077	3.106	3.144	3.190	3.244	3.312
8	3.264	2.736	2.762	2.796	2.837	2.886	2.947
9	2.906	2.432	2.455	2.486	2.523	2.567	2.621
10	2.588	2.162	2.183	2.211	2.244	2.283	2.332
11	2.304	1.921	1.941	1.965	1.995	2.030	2.074
12	2.052	1.708	1.726	1.748	1.774	1.806	1.846
13	1.829	1.520	1.536	1.556	1.579	1.608	1.643
14	1.628	1.351	1.365	1.383	1.404	1.430	1.461
15	1.450	1.201	1.213	1.230	1.249	1.272	1.300
16	1.290	1.067	1.078	1.092	1.109	1.130	1.156
17	1.151	0.950	0.960	0.973	0.989	1.007	1.030
18	1.024	0.844	0.853	0.865	0.878	0.895	0.916
19	0.912	0.750	0.759	0.769	0.781	0.796	0.815
20	0.813	0.668	0.675	0.685	0.696	0.709	0.726
21	0.724	0.594	0.600	0.609	0.619	0.631	0.646
22	0.643	0.527	0.533	0.540	0.549	0.560	0.573
23	0.574	0.470	0.475	0.481	0.489	0.499	0.511
24	0.511	0.418	0.422	0.428	0.435	0.444	0.455
25	0.455	0.371	0.375	0.381	0.387	0.395	0.405
26	0.404	0.329	0.333	0.338	0.344	0.350	0.359
27	0.361	0.294	0.297	0.302	0.307	0.313	0.321
28	0.320	0.260	0.263	0.267	0.272	0.277	0.284
29	0.287	0.233	0.236	0.239	0.243	0.248	0.255
30	0.254	0.206	0.209	0.212	0.215	0.220	0.225

Download this mode’s original CSV

Separate comparison: equal DC resistance at 20°C

20°C, equal length and equal DC resistance. This is not an equal-current table; no bare-wire or PVC temperature-rise scenario is applied.

Use this separate resistance comparison to distinguish electrical resistance from thermal current matching. It does not certify current capacity or authorize conductor substitution.

Values: equivalent solid copper METAL diameter in mm. Copper-content columns refer to CCA mass percentages.

On narrow screens, scroll the table horizontally. The table region is keyboard focusable.

Separate comparison: equal DC resistance at 20°C — metal diameter (mm); copper by mass
CCA AWG	CCA metal Ø (mm)	21% Cu by mass	30% Cu by mass	40% Cu by mass	50% Cu by mass	60% Cu by mass	70% Cu by mass
6	4.115	3.289	3.330	3.382	3.444	3.520	3.614
7	3.665	2.930	2.965	3.012	3.067	3.135	3.218
8	3.264	2.609	2.641	2.682	2.732	2.792	2.866
9	2.906	2.323	2.351	2.388	2.432	2.486	2.552
10	2.588	2.069	2.094	2.127	2.166	2.214	2.273
11	2.304	1.842	1.864	1.893	1.928	1.971	2.023
12	2.052	1.640	1.660	1.686	1.717	1.755	1.802
13	1.829	1.462	1.480	1.503	1.531	1.564	1.606
14	1.628	1.301	1.317	1.338	1.363	1.392	1.430
15	1.450	1.159	1.173	1.192	1.214	1.240	1.273
16	1.290	1.031	1.044	1.060	1.080	1.103	1.133
17	1.151	0.920	0.931	0.946	0.963	0.984	1.011
18	1.024	0.819	0.829	0.842	0.857	0.876	0.899
19	0.912	0.729	0.738	0.749	0.763	0.780	0.801
20	0.813	0.650	0.658	0.668	0.680	0.695	0.714
21	0.724	0.579	0.586	0.595	0.606	0.619	0.636
22	0.643	0.514	0.520	0.528	0.538	0.550	0.565
23	0.574	0.459	0.464	0.472	0.480	0.491	0.504
24	0.511	0.408	0.413	0.420	0.428	0.437	0.449
25	0.455	0.364	0.368	0.374	0.381	0.389	0.400
26	0.404	0.323	0.327	0.332	0.338	0.346	0.355
27	0.361	0.289	0.292	0.297	0.302	0.309	0.317
28	0.320	0.256	0.259	0.263	0.268	0.274	0.281
29	0.287	0.229	0.232	0.236	0.240	0.245	0.252
30	0.254	0.203	0.206	0.209	0.213	0.217	0.223

Download this mode’s original CSV

Method, limitations and traceability

Straight, long, isolated horizontal wire in still air; no solar load or nearby surfaces, bundling, conduit, forced airflow, harmonics, termination loss or end cooling. DC steady-state model; no implied approval for 50/60 Hz, high-frequency or harmonic applications.

Conductivity in %IACS is not copper content. The six copper mass fractions correspond to these modelled volume fractions:

21% mass → 7.429% volume
30% mass → 11.456% volume
40% mass → 16.754% volume
50% mass → 23.189% volume
60% mass → 31.170% volume
70% mass → 41.329% volume

Calculation coverage is not a supply catalogue. AWG 6 is 4.115 mm, beyond the 4.00 mm round-wire range in the referenced earlier specification; 21% is a new composition point. Availability, composition tolerances and diameter tolerances require separate confirmation. The earlier range is not stated as a permanent manufacturing limit.

Calculation method and input basis

Ordinary electrical-aluminium-core CCA: convert copper mass fraction to volume fraction, then calculate longitudinal resistivity using the parallel-conduction model. Constituent model: Spec-CCA-UNTINNED Rev.2, 2026-06-17, not September 2026 measured performance. Cu/Al density: 8.960/2.705 g/cm³; 20°C resistivity: 0.017241/0.028264 Ω·mm²/m. Common resistance temperature coefficient 0.004/K is an engineering approximation.

The all-range squared Churchill–Chu horizontal-cylinder expression is used. Air properties are interpolated at film temperature; convection and radiation balance I²R heating per metre. The PVC case includes cylindrical insulation conduction and solves for outer-surface temperature. Each AWG/composition pair is solved independently, without fixed diameter scaling. Metal cross-sections are approximately isothermal, with fully developed end-current transfer.

Nominal SI diameters use the public ASTM B258-18 table: 12 AWG = 2.052 mm; 30 AWG = 0.254 mm. Areas use those listed diameters, not unrounded mathematical AWG values. Solver residuals verify numerical closure, not physical accuracy or experimental validation.

Nu = [0.60 + 0.387 Ra^(1/6) / (1 + (0.559/Pr)^(9/16))^(8/27)]²

Sources

User material model: Spec-CCA-UNTINNED Rev.2, 2026-06-17, section 3.1
ASTM B258-18, public preview, Table 1
ASTM current B258 scope page
Churchill & Chu horizontal-cylinder correlation, ht implementation documentation
Maya HTT atmospheric-air property table
Cableizer insulation thermal resistivity

These sources support the calculation method and input basis; they do not certify or endorse this table.

Results are copper metal diameters in millimetres, excluding insulation. Copper content is expressed by mass. These calculations are conditional references, not certified current ratings, standard-gauge substitution instructions or supply commitments.