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Watts to Amps Calculator
 

 

Single - Phase
Full Load Amps
HP 115V 208V 230V
1/6 4.4 2.4 2.2
1/4 5.8 3.2 2.9
1/3 7.2 4 3.6
1/2 9.8 5.4 4.9
3/4 13.8 7.6 6.9
1 16 8.8 8
1-1/2 20 11 10
2 24 13.2 12
3 34 18.7 17
5 56 30.8 28
7-1/2 80 44 40
10 100 55 50


Three - Phase
Full Load Amps
HP 115V 208V 230V 460V
0.50 4 2.2 2 1
0.75 5.6 3.1 2.8 1.4
1.0 7.2 4.0 3.6 1.8
1.50 10.4 5.7 5.2 2.6
2.0 13.6 7.5 6.8 3.4
3.0 - 10.6 9.6 4.8
5 - 16.7 15.2 7.6
7.5 - 24.2 22.0 11.0
10 - 30.8 28.0 14.0
15 - 46.2 42.0 21.0
20 - 59.4 54.0 27.0
25 - 74.8 68.0 34.0
30 - 88.0 80.0 40.0
40 - 114.4 104.0 52.0
50 - 143.0 130.0 65.0


SINGLE PHASE
Transformer Full Load Current In Amps
Dry-Type Distribution Transformers
KVA Rated Line Voltage
120 240 480 600
1 8.3 4.2 2.1 1.7
1.5 12.5 6.3 3.1 2.5
2 16.7 8.3 4.2 3.3
3 25.0 12.5 6.3 5.0
5 41.7 20.8 10.4 8.3
7.5 62.5 31.3 15.6 12.5
10 83.3 41.7 20.8 16.7
15 125.0 62.5 31.3 25.0
25 208.3 104.2 52.1 41.7
37.5 312.5 156.3 78.1 62.5
50 416.7 208.3 104.2 83.3
75 625.0 312.5 156.3 125.0
100 833.3 416.7 208.3 166.7
167 1391.7 695.8 347.9 278.3
250 2083.3 1041.7 520.8 416.7
333 2775.0 1387.5 693.8 555.0
500 4166.7 2083.3 1041.7 833.3


Single Phase Calculation
KVA = Volts x Amps
1000
 
Amps = kVA x 1000
Volts


THREE PHASE
Transformer Full Load Current In Amps
Dry-Type Distribution Transformers
KVA Rated Line Voltage
208 240 480 600
3 8.3 7.2 3.6 2.9
6 16.7 14.4 7.2 5.8
9 25.0 21.6 10.8 8.7
15 41.6 36.1 18.0 14.4
30 83.3 72.2 36.1 28.9
45 125.0 108.4 54.2 43.3
75 208.2 180.4 90.2 72.2
112.5 312.5 271.6 135.3 108.2
150 416.3 360.8 180.4 144.3
225 625.0 541.9 270.7 216.5
300 832.7 721.7 360.8 288.7
500 1387.8 1202.8 601.4 481.1
750 2081.9 1804.3 902.1 721.7
1000 2405.7 2405.7 1202.9 962.3


Three Phase Calculation
KVA = 1.732 x Volts x Amps
1000
 
Amps = kVA x 1000
1.732 x Volts


Table 310-16. Allowable Ampacities of Insulated Conductors Rated 0-2000 Volts, 60 degrees to 90 degrees Celsius (140 - 194 Fahrenheit) Not More Than Three Conductors in Raceway or Cable or Earth (Directly Buried), Based on Ambient Air Temperature of 30 Degrees Cellulosic (86 Degrees Fahrenheit)
 
60°C
(140°F)		 75°C
(167°F)		 90°C
(194°F)		 60°C
(140°F)		 75°C
(167°F)		 90°C
(194°F)
AWG

MCM		 TYPES

TW
UF		 TYPES

FEPW
RH
RHW
THW
THWN
XHHW
USE		 TYPES
TA. TBS
SA. SIS

FEP
FEPB
RHH
THHN
XHHW		 TYPES

TW
UF		 TYPES

FEPW
RH
RHW
THW
THWN
XHHW
USE		 TYPES
TA. TBS
SA. SIS

FEP
FEPB
RHH
THHN
XHHW
SIZE COPPER ALUMINUM OR COPPER CLAD ALUMINUM
14 20* 20* 25*      
12 25* 25* 30* 20* 20* 25*
10 30 35* 40* 25 30* 35*
8 40 50 55 30 40 45
6 55 65 75 40 50 60
4 70 85 95 55 65 75
3 85 100 110 65 75 85
2 95 115 130 75 90 100
1 110 130 150 85 100 115
1/0 125 150 170 100 120 135
2/0 145 175 195 115 135 150
3/0 165 200 225 130 155 175
4/0 195 230 260 150 180 205
250 215 255 290 170 205 230
300 240 285 320 190 230 255
350 260 310 350 210 250 280
400 280 335 380 225 270 305
500 320 380 430 260 310 350
*Unless otherwise specifically permitted eleswhere in this Code, the overcurrent protection for conductor types marked with a * shall not exceed 15 amperes for No. 14,20 aperes for No. 12, and 30 amperes for No. 10 copper.


EQUIPMENT GROUNDING CONDUCTORS FOR GROUNDING RACEWAY AND EQUIPMENT
CIRCUIT AMPERES
COPPER AWG ALUMINUM AWG
15 14 12
20 12 10
30 10 8
     
40 10 8
60 10 8
100 8 6
     
200 6 4
300 4 2
400 3 1
     
500 2 1/0
600 1 2/0
800 0 3/0
     
1000 2/0 4/0
1200 3/0 250 kcmil


AC SYSTEM GROUNDING ELECTRODE
SERVICE CONDUCTOR AWG
GROUNDING ELECTRODE CONNECTOR
COPPER ALUMINUM COPPER ALUMINUM
2 or smaller 1/0 or smaller 8 6
1 or 1/0 2/0 or 3/0 6 4
Over 3/0 thru 350 kcmil Over 250 kcmil thru 500 kcmil 2 1/0
Over 350 kcmil thru 600 kcmil Over 500 kcmil thru 900 kcmil 1/0 3/0


 

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