# Acceptable percentage of voltage drop

I'm hoping someone can give me a an answer to this I've gotten mixed information.
I'm wanting to run power to my lake cabin without having to down hundreds of
trees for a power company right-of-way.
My problem is that my 200 AMP service panel will be about 300 feet from the power drop and meter base.
From my calculations, 240 volts (single phase) using 2- 3/0 copper conductors with a 2/0 neutral will yield a voltage drop of about 9.1 volts or 3.8% is this acceptable for most household uses?
Won't I still be getting about 230 volts and 115 volts on my household loads?
I've read that most consider 5% the upper limit.
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I didn't check you calculations, but I would just add that youir calculated voltage drop will only occur with a 200 amp load.
5% is the generally accepted total drop, including both feeder and branch circuit. You have already used up 3.8% in the feeder. What is the connected load like? Do you have electric heat, or something else that is going to draw a lot of current?
200 amps at 230 is 46 kilowatts, which is about 157,000 BTU. You can heat a decent sized residence with that much power.

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I'll probably be running:
2-ton AC (40 AMPS) Central Heat (50 AMPS) Electric Range (40 AMPS) Well Pump (20 AMPS)
The killer is the "On-Demand" Water heater that's rated at 16KW pulling 100 AMPS
Still think I have enough juice? ;-)
in article F4idnXShsOp2Bj snipped-for-privacy@giganews.com, BFoelsch at snipped-for-privacy@comcast.ditch.this.net wrote on 11/22/04 8:09 PM:

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hundreds
volts
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in article OpudnesoVtH8IT snipped-for-privacy@adelphia.com, TimPerry at snipped-for-privacy@noaspamadelphia.net wrote on 11/22/04 10:28 PM:

If 3/0 isn't big enough, I may have to go to propane.
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gotten mixed

having to down

3/0 copper

on my household

Propane would be smart.
btw your 2 ton ac will draw approx 10 amps at 230 volts...depending on the heat of the day etc. .. and the efficiency rating of the unit. It should be on a 20 amp two pole breaker with size 12 awg minimum, in your situation Id run 10 awg wire.
Phil Scott

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So, do you think I would be better off running 4/0?
in article cozod.24995\$ snipped-for-privacy@newssvr14.news.prodigy.com, Phil Scott at snipped-for-privacy@sf.sbcglobal.net wrote on 11/22/04 10:54 PM:

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I've
2-
drop
volts
two
Id
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gotten mixed

to down hundreds

300 feet from

3/0 copper

my household

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Yes. Undoubtedly.

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hundreds
volts
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in article _YudneuQ1MOpLz snipped-for-privacy@adelphia.com, TimPerry at snipped-for-privacy@noaspamadelphia.net wrote on 11/22/04 9:44 PM:

I used a similar calculator to come up with my original figures. However, this calculator arrives at a slightly lower figure.
The question was: what is an acceptable percentage of voltage drop on a single phase 240 volt circuit @ 200 amps.
I guess I should add that this will be buried either in conduit or directly depending on the costs.
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gotten mixed

to down

I hadnt noticed this before....300' and 9 volt drop... thats too much for the compressors...but wont make any difference to the water heater and lights.. you will have trouble with AC compressors with that set up, adding another 3 v drop in your house wiring. Thats 12 or 13 v drop... another 10 or 15 volt drop for summer brown out conditions added in.. ..and you get AC compressor motor burn out issues.
I would have the utility upgrade the feeders...or use a heat pump for heating the water instead of the instantaneous electric resistance... get the total load down so the voltage drop stays under 10 or 12% worst case with local area grid brown out factored in.
Phil Scott

3/0 copper

on my household

figures. However,

voltage drop on a

conduit or directly

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directly
do you really know what your line voltage at the meter is actually going to be? several of my sites that are supposed to be 208 are actually 202 (on a good day) and often less then 200. the power company thinks this is just fine.
this means it take more current to do the same work that is needed. the I squared R losses increase, transformers run hotter, breakdowns are more frequent then they should be.
i wonder if you could get water and air heat in 3 phase versions (and get 3 phase service)?
(the copper and labor for one 400A 3 phase run of 100 ft was \$7,000 this summer)
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figures. However,

voltage drop on a

conduit or

actually going to

actually 202 (on a

this is just

needed. the I

breakdowns are more

versions (and get 3

You can do that...but running 3 phase service to a cabin is just unheard of...and it will cost. Better he take his own advice and go to propane for heat.
Phil Scott

\$7,000 this

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wrote on 11/22/04 9:44 PM:

The cost of running this underground in conduit would be crazy. UF cable would make more sense.
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in article snipped-for-privacy@uni-berlin.de, Bob Peterson at snipped-for-privacy@insightbb.com wrote on 11/22/04 11:36 PM:

I agree, especially since I'm a rank amateur. However, I'm having trouble finding a local supplier for UF cable of that size.
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wrote on 11/22/04 9:44 PM:

conduit or

crazy. UF cable

having trouble

Like bob said, you have a diverse load... all of it will not be running at one time..Id dump the instantaneous electric water heater though for sure..or go to one with a 20 amp heater element and tank,..or propane.
Phil Scott

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if you are a rank amateur you are better off letting someone who knows what they are doing take care of it.
Having said that, any electrical supply house can special order you whatever you need.
wrote on 11/22/04 9:44 PM: