Q) What does it cost per year, at 6.78 cents per KWH, for the power loss of two 20 AWG circuit conductors with a total resistance of 0.40 ohms with a current flow of 20 amps?

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## Code question of the day weekend edition

First, let's find out how much power is lost due to the resistance of the conductors. This can be calculated using Ohm's law (V = IR) and the power law (P = VI).

Calculate voltage drop using Ohm's law:

Voltage drop (V) = Current (I) * Resistance (R)

= 20 Amps * 0.40 Ohms

= 8 Volts

Calculate power loss using the power law:

Power Loss (P) = Voltage (V) * Current (I)

= 8 Volts * 20 Amps

= 160 Watts

That's the power lost per instant. Now, to find out how much it costs for a year, we need to convert the power loss into kilowatts, find out how much energy is used in a year, and then multiply by the cost per kilowatt-hour.

Convert power loss to kilowatts:

160 Watts = 0.16 kilowatts (kW)

Calculate energy used in a year:

Energy used (E) = Power (P) * Time (T)

= 0.16 kW * (24 hours/day * 365 days/year)

= 1,401.6 kilowatt-hours (kWh)

Calculate cost:

Cost = Energy used (E) * Cost per kWh

= 1,401.6 kWh * $0.0678 per kWh

= approximately $94.99

So, the power loss of two 20 AWG circuit conductors with a total resistance of 0.40 ohms with a current flow of 20 amps, at 6.78 cents per kWh, costs approximately $94.99 per year.

Calculate voltage drop using Ohm's law:

Voltage drop (V) = Current (I) * Resistance (R)

= 20 Amps * 0.40 Ohms

= 8 Volts

Calculate power loss using the power law:

Power Loss (P) = Voltage (V) * Current (I)

= 8 Volts * 20 Amps

= 160 Watts

That's the power lost per instant. Now, to find out how much it costs for a year, we need to convert the power loss into kilowatts, find out how much energy is used in a year, and then multiply by the cost per kilowatt-hour.

Convert power loss to kilowatts:

160 Watts = 0.16 kilowatts (kW)

Calculate energy used in a year:

Energy used (E) = Power (P) * Time (T)

= 0.16 kW * (24 hours/day * 365 days/year)

= 1,401.6 kilowatt-hours (kWh)

Calculate cost:

Cost = Energy used (E) * Cost per kWh

= 1,401.6 kWh * $0.0678 per kWh

= approximately $94.99

So, the power loss of two 20 AWG circuit conductors with a total resistance of 0.40 ohms with a current flow of 20 amps, at 6.78 cents per kWh, costs approximately $94.99 per year.

Best Regards,

Fast Trax® System

Electrical Code Academy, Inc.

Paul.Abernathy@fasttraxsystem.com

**Paul W. Abernathy, CMECP®**Fast Trax® System

Electrical Code Academy, Inc.

Paul.Abernathy@fasttraxsystem.com