30 CFR Appendix Appendix I to Subpart D of Part 18 Appendix I to Subpart D of Part 18 | Code of Federal Regulations | US Law

30 CFR Appendix Appendix I to Subpart D of Part 18

Appendix I to Subpart D of Part 18

May 28, 2026

CFR

Appendix I to Subpart D of Part 18

LIST OF TABLES
Table No.	Title
1	Portable power cable ampacities—600 volts.
2	Portable cord ampacities—600 volts.
3	Portable power cable ampacities—601 to 5,000 volts.
4	Normal diameter of round cables with tolerances in inches—600 volts.
5	Nominal dimension of flat cables with tolerances in inches—600 volts.
6	Nominal diameter of heavy jacketed cords with tolerances in inches—600 volts.
7	Nominal diameter of three-conductor portable power cables with tolerances in inches—601 to 5,000 volts.
8	Fuse ratings or instantaneous settings of circuit breakers for short-circuit protection of portable cables.
9	Specifications for portable cables longer than 500 feet.
10	High voltage trailing cable ampacities and outside diameters.

Open Table

Table 1—Portable Power Cable Ampacities—600 Volts (Amperes Per Conductor Based on 60 °C. Copper Temperature—40 °C. Ambient)
Conductor size—AWG or MCM	Single conductor	2-conductor, round or flat	3-conductor, round or flat	4-conductor	5-conductor	6-conductor
8	45	40	35	30	25	20
6	60	50	50	40	35	30
4	85	70	65	55	45	35
3	95	80	75	65	55	45
2	110	95	90	75	65	55
1	130	110	100	85	75	65
1/0	150	130	120	100	90	80
2/0	175	150	135	115	105	95
3/0	205	175	155	130	120	110
4/0	235	200	180	150	140	130
250	275	220	200	160
300	305	240	220	175
350	345	240	235	190
400	375	280	250	200
450	400	300	270	215
500	425	320	290	230

Open Table

Table 2—Portable Cord Ampacities—600 Volts (Amperes Per Conductor Based on 60 °C. Copper Temperature—40 °C. Ambient)
Conductor size—AWG	1-3 conductor	4-6 conductor	7-9 conductor
14	15	12	8
12	20	16	11
10	25	20	14

Open Table

Table 3—Portable Power Cable Ampacities—601 to 5,000 Volts (Amperes Per Conductor Based on 75 °C. Copper Temperature—40 °C. Ambient)
Conductor size—AWG or MCM	3-conductor types G-GC and SIIC-GC 2,000 volts	3-conductor type SHD-GC 2,001-5,000 volts
6	65	65
4	85	85
3	100	100
2	115	115
1	130	130
1/0	145	145
2/0	170	170
3/0	195	195
4/0	220	220
250	245	245
300	275	275
350	305	305

Open Table

Table 4—Nominal Diameters of Round Cables With Tolerances in Inches—600 Volts
Conductor size—AWG or MCM	Single conductor	2-conductor			3-conductor			4-conductor—Types W & G	5-conductor—Types W & G	6-conductor
Conductor size—AWG or MCM	Single conductor	Types W & G twisted	Type PG, 2 power	Type PCG, 3 power, ground	Types W & G	Type PG, 3 power, ground	Type PCG, 3 power, 2 control, ground	4-conductor—Types W & G	5-conductor—Types W & G	Type w	Tolerance
8	0.44	0.81	0.84	0.94	0.91	0.93	1.03	0.99	1.07	1.18	±0.03
6	.51	.93	.93	.98	1.01	1.03	1.18	1.10	1.21	1.31	±.03
4	.57	1.08	1.08	1.10	1.17	1.20	1.29	1.27	1.40	1.52	±.03
3	.63	1.17	1.17	1.20	1.24	1.27	1.31	1.34	1.48	1.61	±.03
2	.66	1.27	1.27	1.29	1.34	1.34	1.39	1.48	1.61	1.75	±.03
1	.74	1.44	1.44	1.44	1.51	1.52	1.52	1.68	1.88	2.05	±.03
1/0	.77	1.52	1.52	1.52	1.65	1.68	1.68	1.79	1.96	2.13	±.04
2/0	.82	1.65	1.65	1.65	1.75	1.79	1.79	1.93	2.13	2.32	±.04
3/0	.87	1.77	1.77	1.77	1.89	1.93	1.93	2.07	2.26	2.49	±.05
4/0	.93	1.92	1.92	1.92	2.04	2.13	2.13	2.26	2.46	2.71	±.05
250	1.03	2.16	2.16	2.16	2.39	2.39	2.39	2.66			±.06
300	1.09	2.32			2.56			2.84			±.06
350	1.15	2.43			2.68			2.98			±.06
400	1.20	2.57			2.82			3.14			±.06
450	1.26	2.67			2.94			3.26			±.06
500	1.31	2.76			3.03			3.40			±.06

Open Table

Table 5—Nominal Dimensions of Flat Cables With Tolerances in Inches—600 Volts
Conductor size—AWG	2-conductor								3-conductor—Type G
	Type W				Type G				Major		Minor
	Major		Minor		Major		Minor		O.D.	Tolerance	O.D.	Tolerance
	O.D.	Tolerance	O.D.	Tolerance	O.D.	Tolerance	O.D.	Tolerance	O.D.	Tolerance	O.D.	Tolerance
8	0.84	±0.04	0.51	±0.03
6	.93	±.04	.56	±.03	1.02	±.04	0.56	±.03	1.65	±0.06	0.67	±0.05
4	1.05	±.04	.61	±.03	1.15	±.04	.61	±.03	1.85	±.06	.75	±.05
3	1.14	±.04	.68	±.03	1.26	±.04	.68	±.03	1.99	±.06	.77	±.05
2	1.24	±.04	.73	±.03	1.35	±.04	.73	±.06	2.10	±.06	.81	±.05
1	1.40	±.04	.81	±.03	1.55	±.04	.81	±.03	2.43	±.06	.97	±.05
1/0	1.51	±.04	.93	±.03	1.67	±.04	.93	±.03
2/0	1.63	±.04	.99	±.03	1.85	±.04	.99	±.03
3/0	1.77	±.04	1.03	±.03	2.00	±.04	1.03	±.03
4/0	1.89	±.04	1.10	±.03	2.10	±.04	1.10	±.03

Open Table

Table 6—Nominal Diameters of Heavy Jacketed Cords With Tolerances In Inches—600 Volts
Conductor size—AWG	2-conductor		3-conductor		4-conductor		5-conductor		6-conductor		7-conductor
Conductor size—AWG	Diameter	Tolerance	Diameter	Tolerance	Diameter	Tolerance	Diameter	Tolerance	Diameter	Tolerance	Diameter	Tolerance
14	0.64	±0.02	0.67	±0.02	0.71	±0.02	0.78	±0.03	0.83	±0.03	0.89	±0.03
12	.68	±.02	.72	±.03	.76	±.03	.83	±.03	.89	±.03	.98	±.03
10	.73	±.03	.80	±.03	.84	±.03	.90	±.03	1.00	±.03	1.07	±.03

Open Table

Table 7—Nominal Diameters of Three-Conductor Portable Power Cables With Tolerances in Inches—601 to 5,000 Volts
Conductor size—AWG or MCM	Type G-GC (nonshielded) 2,000 volts		Type SHC-GC (shielded overall) 2,000 volts		Type SHD-GC (individually shielded power conductors) 2,001-3,000 volts		Type SHD-GC (individually shielded power conductors) 3,001-5,000 volts
Conductor size—AWG or MCM	Diameter	Tolerance	Diameter	Tolerance	Diameter	Tolerance	Diameter	Tolerance
6	1.25	+ 0.10, −0.06	1.39	+ 0.11, −0.07	1.62	+ 0.13, −0.08	1.78	+ 0.14, −0.09
4	1.40	+ .11, −.07	1.55	+ .12, −.08	1.77	+ .14, −.09	1.90	+ .15, −.10
3	1.48	+ .12, −.07	1.62	+ .13, −.08	1.84	+ .15, −.09	1.98	+ .16, −.10
2	1.55	+ .12, −.08	1.71	+ .14, −.09	1.92	+ .15, −.10	2.09	+ .17, −.11
1	1.74	+ .14, −.09	1.89	+ .15, −.09	2.04	+ .16, −.10	2.18	+ .17, −.11
1/0	1.84	+ .15, −.09	2.02	+ .16, −.10	2.18	+ .17, −.11	2.34	+ .19, −.12
2/0	1.99	+ .16, −.10	2.16	+ .17, −.11	2.29	+ .18, −.12	2.46	+ .20, −.12
3/0	2.12	+ .17, −.11	2.30	+ .18, −.11	2.45	+ .20, −.12	2.62	+ .21, −.13
4/0	2.30	+ .18, −.12	2.48	+ .20, −.12	2.62	+ .21, −.13	2.76	+ .22, −.14
250	2.46	+ .20, −.12	2.70	+ .22, −.13
300	2.63	+ .21, −.13	2.84	+ .23, −.14
350	2.75	+ .22, −.14	2.97	+ .24, −.15

Open Table

Table 8—Fuse Ratings or Instantaneous Setting of Circuit Breakers for Short-Circuit Protection of Portable Cables and Cords
Conductor size—AWG or MCM	Ohms/1,000 ft. at 25 °C.	Maximum allowable fuse rating (amperes)	Maximum allowable circuit breaker instantaneous setting (amperes) ¹
14	2.62	20	50
12	1.65	30	75
10	1.04	40	150
8	.654	80	200
6	.410	100	300
4	.259	200	500
3	.205	250	600
2	.162	300	800
1	.129	375	1,000
1/0	.102	500	1,250
2/0	.081		1,500
3/0	.064		2,000
4/0	.051		2,500
250	.043		2,500
300	.036		2,500
350	.031		2,500
400	.027		2,500
450	.024		2,500
500	.022		2,500
¹ Higher circuit-breaker settings may be permitted for special applications when justified.

Open Table

Table 9—Specifications for Portable Cables Longer Than 500 Feet ¹
Conductor size—AWG or MCM	Max. allowable length (feet)	Normal ampacity at 60 °C. copper temperature (40 °C. ambient)	Resistance at 60 °C. copper temperature (ohms)
6	550	50	0.512
4	600	70	.353
3	650	80	.302
2	700	95	.258
1	750	110	.220
1/0	800	130	.185
2/0	850	150	.157
3/0	900	175	.130
4/0	1,000	200	.116
250	1,000	220	.098
300	1,000	240	.082
350	1,000	260	.070
400	1,000	280	.061
450	1,000	300	.054
500	1,000	320	.050
¹ Fuses shall not be used for short-circuit protection of these cables. Circuit breakers shall be used with the instantaneous trip settings not to exceed the values given in Table 8.

Open Table

Table 10—High Voltage Trailing Cable Ampacities and Outside Diameters
Power conductor	Ampacity *	Outside diameter ** (inches)
Size AWG or kcmil	Amperes per conductor	SHD-GC 2001 to 5000 volts	SHD-CGC 2001 to 5000 volts	SHD-PCG 2001 to 5000 volts
6	93	1.56	1.62
4	122	1.68	1.73
3	140	1.78	1.82	1.94
2	159	1.87	1.91	2.03
1	184	1.95	1.98	2.12
1/0	211	2.08	2.10	2.26
2/0	243	2.20	2.20	2.40
3/0	279	2.36	2.36	2.58
4/0	321	2.50	2.50	2.76
250	355	2.69	2.69
300	398	2.81	2.81
350	435	2.95	2.95
500	536	3.31	3.31
* These ampacities are based on single isolated conductor in air, operated with open-circuited shield for a 90 °C conductor temperature and an ambient temperature of 40 °C.
** Tolerances for the outside diameter are + 8%/−5%.

[33 FR 4660, Mar. 19, 1968; 33 FR 6345, Apr. 26, 1968, as amended at 42 FR 8373, Feb. 10, 1977; 75 FR 17549, Apr. 6, 2010; 75 FR 20918, Apr. 22, 2010]

Tried the LawStack mobile app?

Join thousands and try LawStack mobile for FREE today.

Carry the law offline, wherever you go.
Download CFR, USC, rules, and state law to your mobile device.

Conductor size—AWG or MCM	Single conductor	2-conductor, round or flat	3-conductor, round or flat	4-conductor	5-conductor	6-conductor
8	45	40	35	30	25	20
6	60	50	50	40	35	30
4	85	70	65	55	45	35
3	95	80	75	65	55	45
2	110	95	90	75	65	55
1	130	110	100	85	75	65
1/0	150	130	120	100	90	80
2/0	175	150	135	115	105	95
3/0	205	175	155	130	120	110
4/0	235	200	180	150	140	130
250	275	220	200	160
300	305	240	220	175
350	345	240	235	190
400	375	280	250	200
450	400	300	270	215
500	425	320	290	230

Conductor size—AWG or MCM	3-conductor types G-GC and SIIC-GC 2,000 volts	3-conductor type SHD-GC 2,001-5,000 volts
6	65	65
4	85	85
3	100	100
2	115	115
1	130	130
1/0	145	145
2/0	170	170
3/0	195	195
4/0	220	220
250	245	245
300	275	275
350	305	305

Conductor size—AWG or MCM	Single conductor	2-conductor, round or flat	3-conductor, round or flat	4-conductor	5-conductor	6-conductor
8	45	40	35	30	25	20
6	60	50	50	40	35	30
4	85	70	65	55	45	35
3	95	80	75	65	55	45
2	110	95	90	75	65	55
1	130	110	100	85	75	65
1/0	150	130	120	100	90	80
2/0	175	150	135	115	105	95
3/0	205	175	155	130	120	110
4/0	235	200	180	150	140	130
250	275	220	200	160
300	305	240	220	175
350	345	240	235	190
400	375	280	250	200
450	400	300	270	215
500	425	320	290	230

Conductor size—AWG or MCM	3-conductor types G-GC and SIIC-GC 2,000 volts	3-conductor type SHD-GC 2,001-5,000 volts
6	65	65
4	85	85
3	100	100
2	115	115
1	130	130
1/0	145	145
2/0	170	170
3/0	195	195
4/0	220	220
250	245	245
300	275	275
350	305	305

Conductor size—AWG or MCM	Single conductor	2-conductor, round or flat	3-conductor, round or flat	4-conductor	5-conductor	6-conductor
8	45	40	35	30	25	20
6	60	50	50	40	35	30
4	85	70	65	55	45	35
3	95	80	75	65	55	45
2	110	95	90	75	65	55
1	130	110	100	85	75	65
1/0	150	130	120	100	90	80
2/0	175	150	135	115	105	95
3/0	205	175	155	130	120	110
4/0	235	200	180	150	140	130
250	275	220	200	160
300	305	240	220	175
350	345	240	235	190
400	375	280	250	200
450	400	300	270	215
500	425	320	290	230

Conductor size—AWG or MCM	3-conductor types G-GC and SIIC-GC 2,000 volts	3-conductor type SHD-GC 2,001-5,000 volts
6	65	65
4	85	85
3	100	100
2	115	115
1	130	130
1/0	145	145
2/0	170	170
3/0	195	195
4/0	220	220
250	245	245
300	275	275
350	305	305