Can you please tell me if my voltage drop calculation is correct?

[WeWillie]

Can you please tell me if my voltage drop calculation is correct?

If not correct, can you please explain how to correct?

Panel to 5 gang switch box is 40 feet. 20 amp circuit 12/2 wire.

All lights…

• Leg 1 from switch is 80’ with 1 amp load
• Leg 2 from switch is 80’ with 5 amp load
• Leg 3 from switch is 20’ with .25 amp load
• Leg 4 from switch is 40’ with .5 amp load
• Leg 5 from switch is 40’ with .5 amp load

I calculated each leg end to end by adding the 40’ from the panel…

• Leg 1: 40’ + 80’ = 120’ at 1 amp = .38 drop
• Leg 2: 40’ + 80’ = 120’ at 5 amps = 1.91 drop
• Leg 3: 40’ + 20’ = 60’ at .25 amps = .095
• Leg 4: 40’ + 40’ = 80’ at .5 amps = .19
• Leg 5: 40’ + 40’ = 80’ at .5 amps = .19
• Total = 2.765 volt drop

120v – 5% = 114.00 (target)

120v – 2.765% = 116.6820 (actual)

Thanks very much!!!!

 

[Little Bill]

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