| electric & safety |
How do I convert watts to amps and amps to watts?The formula for converting Watts to Amps is : Watts = Amps * VoltsThe formula for converting Amps to Watts is : Amps = Watts / Volts SAFTEY WARNING : Only use 80% of the circuit breaker capacity! Common Conversions North American and other 110 volt countries Lights : 1000W / 110V = 9.1A 600W / 110V = 5.4A 400W / 110V = 3.6A 250W / 110V = 2.3A Circuits : 10A * 110V = 1100W and 80% safe usage is 880W 15A * 110V = 1650W and 80% safe usage is 1320W 25A * 110V = 2750W and 80% safe usage is 2200W 30A * 110V = 3300W and 80% safe usage is 2640W Common Conversions British Commonwealth and other 240 volt countries Lights : 1000W / 240V = 4.1A 600W / 240V = 2.5A 400W / 240V = 1.7A 250W / 240V = 1.1A Circuits : 10A * 240V = 2400W and 80% safe usage is 1920W 15A * 240V = 3600W and 80% safe usage is 2880W 25A * 240V = 6000W and 80% safe usage is 4800W 30A * 240V = 7200W and 80% safe usage is 5760W Remember that a circuit services more than one power outlet. A two outlet wall plug will use only one circuit. There will be more outlets on 240V systems per circuit than there will be in 110V systems. |
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Nominal line voltage in the US is 120 (One Hundred Twenty) Volts.
110V has never been a standard, and has not been used since WW-II.
The discrepancy makes a significant difference in your calculations.
The correct calculations as follows:
Lights :
1000W / 120V = 9.1A
600W / 120V = 5.4A
400W / 120V = 3.9A*
250W / 120V = 2.5A*
Halve current demand for 240V.
*Note corrections for standard current draw.
Circuits :
10A * 120V = 1200W and 80% safe usage is 960W *
15A * 120V = 1800W and 80% safe usage is 1440W
25A * 120V = 3000W and 80% safe usage is 2400W * **
30A * 120V = 3600W and 80% safe usage is 2640W **
*Non standard US residential breakers.
**Not safe to power cord connected devices with cords smaller than 12 Ga, Nor with NEMA5-15 (standard 120V) sockets/plugs.
Remember that a circuit services more than one power outlet. (sometimes)
A two outlet wall plug will use only one circuit. (sometimes)
There will be more outlets on 240V systems per circuit than there will be in 110V systems.
(Not necessarily)