Wire size is determined by amperage and distance. The chart below tells you the wire size you need for 240/120 VAC.

240 VAC Wire Size 120 VAC per leg using copper wire and a 2% voltage drop
120 VAC per leg using copper wire and a 2% voltage drop.

On the left column find the amps that your circuit must supply. Then follow that row to the right until you find the distance of your circuit from the supply to the equipment you are feeding. Don't forget to take into account going up and down walls and around any other obstacles. Then follow it up to find your minimum wire size.

This chart is only intended to be an educational guide. Consult the National Electric Code and other local ordinances.

AMPS	#14	#12	#10	#8	#6	#4	#2	1/0	2/0	3/0	4/0
1	120	281	448	712	1135	1800	2869	4549	7244	11564	14509	18327	23127
2	240	141	224	356	567	900	1435	2275	3622	5782	7255	9164	11564
3	360	94	149	237	378	600	956	1516	2415	3855	4836	6109	7709
4	480	70	112	178	284	450	717	1137	1811	2891	3627	4582	5782
5	600	56	90	142	227	360	574	910	1449	2313	2902	3665	4625
10	1200	28	45	71	113	180	287	455	724	1156	1451	1833	2313
15	1800		30	47	76	120	191	303	483	771	967	1222	1542
20	2400			36	57	90	143	227	362	578	725	916	1156
25	3000				45	72	115	182	290	463	580	733	925
30	3600				38	60	96	152	241	385	484	611	771
35	4200					51	82	130	207	330	415	524	661
40	4800					45	72	114	181	289	363	458	578
50	6000						57	91	145	231	290	367	463
60	7200							76	121	193	242	305	385
70	8400							65	103	165	207	262	330
80	9600								91	145	181	229	289
90	10800									128	161	204	257
100	12000									116	145	183	231
125	15000									93	116	147	185
150	18000									77	97	122	154
175	21000										83	105	132
200	24000											92	116

Wire Size and Voltage Drop for Amps - 240/120 VAC

Wire size is determined by amperage and distance. The chart below tells you the wire size you need for 240/120 VAC.