jar546
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OK Electrical Inspectors and Electricians, is the following scenario I put together correct?
The minimum size copper wire type THHN feeder for a 125 amp sub panel 100' away from the main panel in a 120/240 volt AC system, taking into consideration the National Electrical Code and maximum voltage drop and limited to the 75 degree Celsius column, is 2/0 AWG.
According to the NEC, the maximum allowable voltage drop for feeders and branch circuits is 3% at the farthest outlet of power, distance, and load current.
The wire size selection should be based on the ampacity of the wire, which is the amount of current that a wire can safely carry. The ampacity of a wire is determined by the wire's insulation type, temperature rating, and the ambient temperature.
The ampacity of 2/0 AWG THHN wire is limited to the 75 degree Celsius column in the NEC table 310.16, which allows for a current carrying capacity of 130 amperes. This wire size is more than enough to meet the requirements of a 125 ampere sub panel located 100 feet away from the main panel, while also keeping the voltage drop within the 3% maximum allowable limit.
The voltage drop percentage for a 2/0 AWG THHN copper wire feeder for a 125 amp sub panel 100' away from the main panel in a 120/240 volt AC system, taking into consideration the National Electrical Code and limited to the 75 degree Celsius column, would be approximately 2.4%.
This can be calculated by using the formula: Voltage drop (percentage) = (2 x one-way circuit distance in feet x load current in amperes) / (circular mils of the conductor x CMIL/amp)
The wire resistance per 100ft of 2/0 AWG THHN wire is 0.082 ohms/100ft, and the circular mil area of 2/0 AWG THHN is 240,000 cmil.
Voltage drop (percentage) = (2 x 100 x 125) / (240000 x 0.082) = 2.4%
This answer is code compliant with the NEC because the voltage drop percentage is less than 3%, which is the maximum allowable voltage drop for feeders and branch circuits according to NEC standard.
It's important to note that this is a simplified calculation and does not take into account other factors such as ambient temperature, wire installation conditions, and any other load on the same circuit, which can all affect the final ampacity and voltage drop percentage.
The minimum size copper wire type THHN feeder for a 125 amp sub panel 100' away from the main panel in a 120/240 volt AC system, taking into consideration the National Electrical Code and maximum voltage drop and limited to the 75 degree Celsius column, is 2/0 AWG.
According to the NEC, the maximum allowable voltage drop for feeders and branch circuits is 3% at the farthest outlet of power, distance, and load current.
The wire size selection should be based on the ampacity of the wire, which is the amount of current that a wire can safely carry. The ampacity of a wire is determined by the wire's insulation type, temperature rating, and the ambient temperature.
The ampacity of 2/0 AWG THHN wire is limited to the 75 degree Celsius column in the NEC table 310.16, which allows for a current carrying capacity of 130 amperes. This wire size is more than enough to meet the requirements of a 125 ampere sub panel located 100 feet away from the main panel, while also keeping the voltage drop within the 3% maximum allowable limit.
The voltage drop percentage for a 2/0 AWG THHN copper wire feeder for a 125 amp sub panel 100' away from the main panel in a 120/240 volt AC system, taking into consideration the National Electrical Code and limited to the 75 degree Celsius column, would be approximately 2.4%.
This can be calculated by using the formula: Voltage drop (percentage) = (2 x one-way circuit distance in feet x load current in amperes) / (circular mils of the conductor x CMIL/amp)
The wire resistance per 100ft of 2/0 AWG THHN wire is 0.082 ohms/100ft, and the circular mil area of 2/0 AWG THHN is 240,000 cmil.
Voltage drop (percentage) = (2 x 100 x 125) / (240000 x 0.082) = 2.4%
This answer is code compliant with the NEC because the voltage drop percentage is less than 3%, which is the maximum allowable voltage drop for feeders and branch circuits according to NEC standard.
It's important to note that this is a simplified calculation and does not take into account other factors such as ambient temperature, wire installation conditions, and any other load on the same circuit, which can all affect the final ampacity and voltage drop percentage.