Do I need to be concerned about Voltage drop in branch circuits?

[Toomanytools?]

So getting some wiring done and wondering if I'm overly concerned about voltage drop in my outlets. I ran some in slab conduit but not enough. So the longest run about 120' one way, it will have 2 or 3 outlets and then 2 outlets for garage door openers. The outlets will see occasional shop vac, or battery charger, the vac pulls about 12amps (peak?), the openers 1 amp each. So running 12 gauge NM-B on 20 amp breaker was the plan.

Looking at a Voltage Drop chart 12amp load, 120v, 12 AWG one way run is 78'. If I go to 10AWG length is 124' for 12amp , and 99' for 15amp.
I doubt those things will be used at the same time, but just wondering what would be correct thing to do.
Thanks

 

[pattenp]

Use the #12. A max of 5% VD is acceptable on branch circuit.

 

[fitter30]

https://www.inchcalculator.com/voltage-drop-calculator/
Very easy calculator

 

[nadogail]

The short answer is YES, you need to be concerned; but if your measured voltage drop is within the limits described in other posts your concern does not have to become a worry.

 

[joel63]

https://www.inchcalculator.com/voltage-drop-calculator/
Very easy calculator

Thanks a bunch!

This is awesome!

 

[Toomanytools?]

https://www.inchcalculator.com/voltage-drop-calculator/
Very easy calculator

Thanks that is helpful basically the same as the chart I have which shows 3% VD.

(pattenp)
I thought the NEC recommendation was 3% Feeder, 3% branch and 5% combined max. Anyway thanks.

 

[sberry]

Mine is 123. The compulsive worry about v drop is somewhat a hold over from the old days. Stuff wasn't quite as efficient and nominal was 110. At 123 could drop 10% and still work fine.
The OP of this thread really deserves some credit with this as he knows enough to base it on load demand and not necessarily on the fact that its got a 20A breaker on it.

 

[pattenp]

Thanks that is helpful basically the same as the chart I have which shows 3% VD.

(pattenp)
I thought the NEC recommendation was 3% Feeder, 3% branch and 5% combined max. Anyway thanks.

It's given that the 5% is max on the branch circuit needs to take into account for any VD on the feeder.

 

[sberry]

I had a poco bud pull a load on a service, I was surprised at how good it was. It was a loooong ****** with about 6 houses along the way, during the day, low load but 1 30A and less than 1 drop. The way we speculate about all this I would have guessed it to be marginal,,, but nooo, rips the guts right out of the sockets.
My little comp would trip the breaker, I had to find a long circuit and add some cord to get it to work.

 

[sberry]

I can only think of 2 things at the moment I really remember about voltage drop. Both involved dummies, extension cords with trouble lights on them and welding machines. Not going to detail it but not even bright enough to turn off the 100 watt light.
We got one 12 circuit put in wayyyyy back, whole roll of wire and was meant for cordless phone and cash register, the tender put a coffee pot on it, never gave it a thought, worked like it should.
Good thing we didn't calculate it, might not have worked if we thought about it.
The recommendations are conservative, the services are normally very good, the compulsive worry is not worth it. While the code is a minimum doesn't mean it is inadequate. Some of this has been around near as long as code and everything has got better,,, better wire, better power, higher voltage. Lower watt lights, lower draw motors. Smaller welders on 240. A few more 120v utility tools, some welders and air comps.
Even battery chargers are smaller