Voltage calculation

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zappy

zappy

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CA.
I have been taught that to find the voltage drop you,1.Measure the length going to the outlet and back so 100' to and 100' back = 200'. 2.The amps of the equipment say 16 amps. 3.14awg wire 12.9 ohms. L X I X R divided by 1000 =VD.So 41,280 divided by 1000 =41.28 Then divide 41.28 by 120v. and that gives you the % which is .344%VD Is this right? I know there are other ways to do VD calculations,i just have this way memorized.It hard to teach a old dog new tricks.:)
 
Instead of measuring to the outlet and back, just measure to the outlet and multiply by 2. The reason I say this is because if you have a 3 phase mwbc you simply replace that 2 with 1.732.
 
zappy said:
I have been taught that to find the voltage drop you,1.Measure the length going to the outlet and back so 100' to and 100' back = 200'. 2.The amps of the equipment say 16 amps. 3.14awg wire 12.9 ohms. L X I X R divided by 1000 =VD.So 41,280 divided by 1000 =41.28 Then divide 41.28 by 120v. and that gives you the % which is .344%VD Is this right? I know there are other ways to do VD calculations,i just have this way memorized.It hard to teach a old dog new tricks.:)
Click to expand...
R for #14 = 3.1 and not 12.9 per 1000
200 x 16 x 3.1 = (10 volts/120) x 100= 8.3%.
 
buddhakii said:
Instead of measuring to the outlet and back, just measure to the outlet and multiply by 2. The reason I say this is because if you have a 3 phase mwbc you simply replace that 2 with 1.732.
Click to expand...

Bud,
Good short-cut notation.

Zappy,
Your OHMS spec is off. Check it again.
 
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