Voltage Drop Percentage
- Thread starter laketime
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jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Except for a few applications, fire pumps and sensitive electronic equipment, voltage drop is not an NEC concern. You could use the FPN in 210.19 as guide.
FPN No. 4: Conductors for branch circuits as defined in
Article 100, sized to prevent a voltage drop exceeding
3 percent at the farthest outlet of power, heating, and lighting
loads, or combinations of such loads, and where the
maximum total voltage drop on both feeders and branch
circuits to the farthest outlet does not exceed 5 percent,
provide reasonable efficiency of operation. See FPN No. 2
of 215.2(A)(3) for voltage drop on feeder conductors.
There is no receptacle load calc for resi, it is included in the general lighting load: commercial is 180 VA per receptacle/duplex or 360 for a quad per 220 14 (I) or maybe (K) 1VA per sq ft, depends.
FPN No. 4: Conductors for branch circuits as defined in
Article 100, sized to prevent a voltage drop exceeding
3 percent at the farthest outlet of power, heating, and lighting
loads, or combinations of such loads, and where the
maximum total voltage drop on both feeders and branch
circuits to the farthest outlet does not exceed 5 percent,
provide reasonable efficiency of operation. See FPN No. 2
of 215.2(A)(3) for voltage drop on feeder conductors.
There is no receptacle load calc for resi, it is included in the general lighting load: commercial is 180 VA per receptacle/duplex or 360 for a quad per 220 14 (I) or maybe (K) 1VA per sq ft, depends.
laketime
Senior Member
ok thanks. The project is a marina and we are installing a quad outlet on every dock. So I guess I will use 360/quad
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Wait a minute marinas/docks have their own rules.
laketime
Senior Member
well thats good to know.....lol
laketime
Senior Member
Can you break a run up in sections for voltage drop? Like if the full length of the run is 600' and calcs call for #4 wire, can you run #4 to a junction box and then lower wire size as you get closer to the end of the circuit or do you need to pull a #4 all the way to the end?
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Yes, you can calculate the VD in sections, with reduced conductor sizes as you get closer to the loads. But let me ask for a clarification. Marinas have their own rules, yes. But the rules have to do with the receptacles that serve the boats moored at the docks. Those are either rated 50 amps at 250 volts or 30 amps at 125 volts, and are not compatible with the standard 120 volt household power cords. The code gives relevant demand factors. But if you are talking about a general purpose receptacle on the dock, to be used for plugging in a drill or a fan or something, then I would calculate the VD using 360 VA for a quad.
Electric-Light
Senior Member
Speaking of such situation, what does the code say about the use of transformer right at the load panel?
A 120v 600' run with 4AWG has a drop of 4.5% @ 15A, 6%@20A
If you use 240v and use a 240-120 transformer, you can get away with 10AWG
240v 600' 10AWG @ 7.5A =4.5%, 10A=6% and 10AWG should be just fine for satisfying conductor overload protection requirement for 15A or 20A 240v breaker.
laketime
Senior Member
These are just general use receptacles not meant for shore power for boats.
Umm,
2400VA @ 80%?
If you're talking load calcs for demand, it doesn't matter unless it's for specific equipment.
In the first case it goes under the VA/sq ft, in the second, go back to the 2400VA @ 80%. I'm saying that because if you have a quad serving specific equipment, it'll be close to the max breaker.
2400VA @ 80%?
If you're talking load calcs for demand, it doesn't matter unless it's for specific equipment.
In the first case it goes under the VA/sq ft, in the second, go back to the 2400VA @ 80%. I'm saying that because if you have a quad serving specific equipment, it'll be close to the max breaker.
Cow
Senior Member
- Location
- Eastern Oregon
- Occupation
- Electrician
Can you set a subpanel or two closer to the receptacles?
Instead of running #4 to EVERY quadplex, can you run #2 to a 100 amp sub, then run #10-12's out to the receps? That would help voltage drop out a bunch and save quite a bit of money if it's feasible.
Instead of running #4 to EVERY quadplex, can you run #2 to a 100 amp sub, then run #10-12's out to the receps? That would help voltage drop out a bunch and save quite a bit of money if it's feasible.
Electric-Light
Senior Member
If it's fed from a 100A breaker, you need to place a breaker sized small enough for #10 conductor protection before making that transition
- Location
- Massachusetts
Read the OP, it is a 20 amp 120 volt circuit.
- Location
- Massachusetts
As this is an Article 555 installation and it sounds like you will be splicing a lot do not forgot 555.9
(The following are from the 2008 NEC)
(The following are from the 2008 NEC)
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