External diameter of conductor

The following conductor diameters are typical values as a function of the conductor cross-section.

For IEC sizes, the diameters are taken from IEC 60228 Ed. 3.0 and from HD 603 S2 Part 7 Section A plus HD 620 S2 Part 10 Section F.
For AWG/kcmil, the diameters are taken from UL 1581 Table 20.1 for solid conductor up to 12 AWG and table 20.3 for round stranded compressed conductors plus ASTM B8-11 for sizes larger than 2000 kcmil.

The user can choose an arbitrary value not limited to the values in the choices below, but a warning is indicated if the conductor diameter seem unreasonably small.

For sector-shaped multi-core cables, the conductor diameter is defined as the diameter of the circle circumscribing the sector-shaped conductors. Based on that value, an equivalent diameter of the conductor $d_x$ is calculated.

Symbol

$d_c$

Unit

Related

$A_c$

Cross-sectional area of conductor [mm$^2$]

Used in

$A_c$

Cross-sectional area of conductor [mm$^2$]

$A_i$

Cross-sectional area of insulation [mm$^2$]

$A_{tape}$

Cross-sectional area of bedding/serving tapes [mm$^2$]

$C_{cs}$

Capacitance conductor - shield [F/m]

$d_{ci}$

Internal diameter of conductor [mm]

$D_{cs}$

Diameter over conductor shield [mm]

$d_{ct}$

External diameter of conductor for transient calculations [mm]

$D_i$

Diameter over insulation including insulation screen [mm]

$D_{ins}$

Diameter over insulation [mm]

$D_{is}$

Diameter over insulation screen [mm]

$D_{it}$

Diameter over insulation for transient calculations [mm]

$D_{scb}$

Diameter over screen bedding [mm]

$G_1$

Geometric factor $G_1$

$k_s$

Skin effect coefficient

$\lambda_{12}$

Loss factor of shield by eddy currents

$Q_{ct}$

Thermal capacitance of conductor (IEC 60853) [J/(m.K)]

$r_1$

Radius of the circle circumscribing the shaped conductors [mm]

$r_c$

Radius of conductor [mm]

$r_{isc}$

Radius above the inner semi-conducting layer [mm]

$T_1$

Thermal resistance between one conductor and sheath [K.m/W]

$t_c$

Thickness of hollow conductor [mm]

$T_{ct}$

Thermal resistance of conductor tape [K.m/W]

$T_i$

Thermal resistance of insulation [K.m/W]

$X_G$

Factor $X_G$

$X_K$

Factor $X_K$

$Y_K$

Factor $Y_K$

$y_p$

Proximity effect factor of conductors

Choices

IEC sizes	min.	nom.	Diameter [mm] max.	AWG sizes	min.	nom.	max.
0.5 mm$^2$			0.9	18 AWG	1.0	1.02	1.03
0.75 mm$^2$			1.0	16 AWG	1.26	1.29	1.3
1.0 mm$^2$			1.2	14 AWG	1.6	1.63	1.64
1.5 mm$^2$			1.5	12 AWG	2.01	2.05	2.07
2.5 mm$^2$			1.9	10 AWG	2.82	2.87	2.9
4 mm$^2$			2.4	8 AWG	3.53	3.61	3.63
6 mm$^2$	2.6	2.7	2.8	6 AWG	4.42	4.52	4.57
10 mm$^2$	3.4	3.5	3.7	4 AWG	5.61	5.72	5.77
16 mm$^2$	4.7	4.8	5.0	2 AWG	7.04	7.19	7.26
25 mm$^2$	5.6	6.1	6.5	1 AWG	8.03	8.18	8.26
35 mm$^2$	6.6	7.0	7.4	1/0 AWG	9.02	9.19	9.3
50 mm$^2$	7.7	8.1	8.6	2/0 AWG	10.08	10.3	10.39
70 mm$^2$	9.3	9.6	10.0	3/0 AWG	11.35	11.6	11.71
95 mm$^2$	11.0	12.0	13.4	4/0 AWG	12.75	13.0	13.13
120 mm$^2$	12.3	13.0	15.0	250 kcmil	13.89	14.2	14.33
150 mm$^2$	13.7	14.4	16.2	300 kcmil	15.21	15.5	15.67
185 mm$^2$	15.3	15.8	16.4	350 kcmil	16.46	16.8	16.97
240 mm$^2$	17.6	18.2	18.9	400 kcmil	17.58	17.9	18.11
300 mm$^2$	19.7	20.0	21.1	500 kcmil	19.63	20.0	20.24
400 mm$^2$	22.3	23.0	24.6	600 kcmil	21.56	22.0	22.23
500 mm$^2$	25.3	26.0	26.8	750 kcmil	24.1	24.6	24.84
630 mm$^2$	28.7	30.5	32.5	1000 kcmil	27.81	28.4	28.65
800 mm$^2$	33.0	33.8	34.3	1250 kcmil	31.12	31.8	32.05
1000 mm$^2$	37.0	41.0	42.2	1500 kcmil	34.11	34.8	35.15
1200 mm$^2$		44.3		1750 kcmil	36.83	37.6	37.97
1400 mm$^2$		47.5		2000 kcmil	39.4	40.2	40.61
1600 mm$^2$		50.0		2500 kcmil		46.3
1800 mm$^2$		52.8		3000 kcmil		50.7
2000 mm$^2$		55.5		4000 kcmil		58.6
2500 mm$^2$		62.0		5000 kcmil		65.6
3000 mm$^2$		66.0
3200 mm$^2$		68.0
3500 mm$^2$		70.0