Voltage drop

[JoeNorm]

Another voltage drop question.

Let's say you have a transformer 350' away from a small panel being fed with 240volts. From that panel you have a a 100' extension cord serving a 120v load of interest.

Since the load is 120V is the calc for voltage drop done at 120V all the way back to the transformer? So in this case 450'?

Does the run in 240V gain you anything for a 120V load? I'm a bit confused here.

thanks for the help!

 

[kwired]

yes there is voltage drop in the full 450 feet of path, but the feed to the panel is likely different size conductor so you need to calculate each segment separately and add the two results together to get the net VD over the 450 feet. Plus there mostl likely is other loads on the feed to the panel that would also impact VD on that segment.

 

[quantum]

Another voltage drop question.

Let's say you have a transformer 350' away from a small panel being fed with 240volts. From that panel you have a a 100' extension cord serving a 120v load of interest.

Since the load is 120V is the calc for voltage drop done at 120V all the way back to the transformer? So in this case 450'?

Does the run in 240V gain you anything for a 120V load? I'm a bit confused here.

thanks for the help!

Forget the voltage for a minute. You have current A between the panel and the load, and current B between the transformer and the panel. Calculate them separately.

 

[LarryFine]

As Quantum said, each segment has its own voltage drop dependent on its current. So you'd calculate the 350' section at its current, and the 100' segment at its current.

Voltage drop is dependent on two things: circuit impedance and current; voltage has no direct effect. You will discover why higher voltage is used for greater distance.