VD on Homerun

[mstrlucky74]

Have a (1) ¾” conduit with (3) 1P 20A receptacle circuitsgoing 600’. Would I still be okay to use #10’s to keep VD at about 3%? Thanks.

 

[infinity]

Try this:

http://www.southwire.com/support/voltage-drop-calculator.htm

 

[kwired]

Have a (1) ¾” conduit with (3) 1P 20A receptacle circuitsgoing 600’. Would I still be okay to use #10’s to keep VD at about 3%? Thanks.

what is the load?

 

[infinity]

Voltage would help too.

@120 volts, 20 amps, and 600' minimum size conductor for 3% drop is #1 AWG.

 

[gar]

180129-1057 EST

mstrlucky74:

What kwired said is important.

Not adequate for a radial arm saw, about 1.5 HP and 120 V. You figure out why.

.

 

[mstrlucky74]

yikes your sooo right...120v and each receptacle draws about 3 amps.

 

[LarryFine]

Aside from what was said above, if there is a 3-phase source, run it as a multiwire shared-neutral circuit. Even if not, have the two heavier loads of the three share the neutral. These methods can reduce voltage drop.

Another choice would be a single multi-wire feeder with a small distribution panel at the load end of the run. This would allow a single set of larger conductors to share the voltage drop and may end up costing less.

Three 3-amp loads should not require separate circuits, unless there is a compelling reason to do so. Tell us more.

 

[kwired]

Aside from what was said above, if there is a 3-phase source, run it as a multiwire shared-neutral circuit. Even if not, have the two heavier loads of the three share the neutral. These methods can reduce voltage drop.

Another choice would be a single multi-wire feeder with a small distribution panel at the load end of the run. This would allow a single set of larger conductors to share the voltage drop and may end up costing less.

Three 3-amp loads should not require separate circuits, unless there is a compelling reason to do so. Tell us more.

Actually you would still want to use all three lines with your MWBC. Two lines plus neutral does not leave the neutral carrying imbalance current - it carries about same amount of current as the highest loaded line conductor, adding the third phase to the circuit will bring neutral current down.

 

[LarryFine]

Actually you would still want to use all three lines with your MWBC. Two lines plus neutral does not leave the neutral carrying imbalance current - it carries about same amount of current as the highest loaded line conductor, adding the third phase to the circuit will bring neutral current down.

When I said "Even if not", I meant if the supply is only single-phase. Please read the whole first paragraph again.

 

[kwired]

When I said "Even if not", I meant if the supply is only single-phase. Please read the whole first paragraph again.

OK, I didn't see it that way first time.

 

[mstrlucky74]

Aside from what was said above, if there is a 3-phase source, run it as a multiwire shared-neutral circuit. Even if not, have the two heavier loads of the three share the neutral. These methods can reduce voltage drop.

Another choice would be a single multi-wire feeder with a small distribution panel at the load end of the run. This would allow a single set of larger conductors to share the voltage drop and may end up costing less.

Three 3-amp loads should not require separate circuits, unless there is a compelling reason to do so. Tell us more.

So if I may.... how does a MWBC reduce VD as opposed to running separate neutrals? #of CCC's? thx

 

[kwired]

So if I may.... how does a MWBC reduce VD as opposed to running separate neutrals? #of CCC's? thx

Balanced load each side of the MWBC is essentially same thing as 240 volt circuit. If the 240 drops 5 volts that is only 2.5 drop across each 120 volt segment of it. Now turn one side of the circuit off - other side is still drawing same amps, but returning on neutral now. Still will see that same 5 volts drop but it is a higher percentage of 120 then it is of 240, so it can help with voltage drop, but still can yield just as much in certain circumstances.

When you figure voltage drop on service or feeder you typically assume there will be reasonable neutral balance and figure VD off the 208, 240, 480 value and not so much off the 120 or 277 value - you save those for when you do only have single voltage or you definitely know there will be high unbalance.

 

[LarryFine]

So if I may.... how does a MWBC reduce VD as opposed to running separate neutrals? #of CCC's? thx

Simple answer: each circuit effectively consists of one wire the length of the home run vs. 2 wires per circuit, theoretically halving the VD..