philip1957
New member
- Location
- Oklahoma
With a 60 amp circuit breaker and wires are 3 # 6's, the distance is 120 ft., and the voltage is 480 volts - maximum .24 ohms. What would the impedance be in the wire and how would you calculate it?
Impedance calculation
- Thread starter philip1957
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bphgravity
Senior Member
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- Florida
Re: Impedance calculation
Based on your information, I cannot tell if you are looking for total circuit Z, or the total R of the length of the particular conductor.
total Z = square root of R squared + X squared
total R of the conductor can be found in Table 8 of the NEC.
Is this what you are looking for?????
Based on your information, I cannot tell if you are looking for total circuit Z, or the total R of the length of the particular conductor.
total Z = square root of R squared + X squared
total R of the conductor can be found in Table 8 of the NEC.
Is this what you are looking for?????
physis
Senior Member
Re: Impedance calculation
Unless y our going to wrap those conductors around something a number of times there won't be a significant value of inductive reactance.
Without inductive reactance "impedance" is the same value as the DC resistance.
Based on my tables I get 0.0612 ohms for your conductor run, a little higher if it's aluminum instead of copper.
I think you should be more concerned with temperature and insulation. If you use THHN your conductors will be suitable to carry 75 amps at 194 degrees F. Some other insulations only allow 55 amps at lower temperatures.
Unless y
our going to wrap those conductors around something a number of times there won't be a significant value of inductive reactance.Without inductive reactance "impedance" is the same value as the DC resistance.
Based on my tables I get 0.0612 ohms for your conductor run, a little higher if it's aluminum instead of copper.
I think you should be more concerned with temperature and insulation. If you use THHN your conductors will be suitable to carry 75 amps at 194 degrees F. Some other insulations only allow 55 amps at lower temperatures.
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