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Old 01-27-2016, 07:59 AM   #31
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Voltage drop does not come into play usually until after 500 ft. Usually if there is a drop it is because of low voltage in the first place,

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i understand voltage drop calculations mark. However, when looking at the readout on my load management panel or rechecking with a wiggy, i just don't get that much drop or at least as much as the calculations would indicate i would. (thank goodness since i had already bought and pulled my 200 feet of it...lol) even when i throw everything i can at it to max out load... I agree with you that more distance than the op is going to have would be required to be reason for concern.

Another thing i forgot to mention is that if someone wires a 50 amp plug incorrectly as 120v (by having both hots on the same phase) because they think their rv should not be on 240v, you run the risk of overloading the neutral. A lot of people are still confused by horror stories on the net about wiring a 30 amp plug as 240v and cooking the rv. (which it will..) they automatically think that 240v never applies to an rv because of those incidents when in fact 50 amp is always 240v and an rv that is designed to accept 50 amp is designed to accept 240v...
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Old 01-27-2016, 08:00 AM   #32
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Using the calculator I linked to; the return is there; so don't double the distance.

K4C, I plugged in your data; you would have at least an unloaded 122Vac... Voltage drop a little over 6 at 35A load. Also, that panel is a steal! Thanks pointing that out.

However the OP should be in high cotton running on 6AWG.

Voltage drop comes into play no matter the distance. The smaller the gauge the shorter the distance it stops playing nice. When gauge is too small, it warms up it is wasting $$$ when it melts it costs even more dollars. When appliances and expensive electronics gets low voltage, current rises proportionately and can really get into your wallet. That said, if you manage your usage you can get by with less gauge that is recommended.

I only have 30A service and am running on 10AWG for 65'... Only pulling 20A with lights fridge and A/C running, but I make sure that's all.
My voltage drop is less than 3.
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Old 01-27-2016, 08:19 AM   #33
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As I said, I know what the calculation says. However, I start out with about 119-120V and end up around 117 with all three AC's running. I have a magical setup I guess. LOL.
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Old 01-27-2016, 08:28 AM   #34
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Voltage drop does not come into play usually until after 500 ft. Usually if there is a drop it is because of low voltage in the first place,
I'm not sure how you figure that. If that were true I could run 30 amps at 120 volts on a #10 wire 500 feet and still have acceptable voltage at the destination.

According to my calculation the voltage drop would be 35.4 volts so the final voltage would be 84.6 volts. No 120 volt device that I'm aware of would like that.

One should always consider voltage drop when running more than about 20' of wire.
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Old 01-27-2016, 08:30 AM   #35
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I thought a 3 a/c units are managed and don't run at once??? I just read a 15K btu pulls only 11Amps - running. Startup about 16/17. I don't think your EMS will see startup loads. You didn't say how many amps you are pulling when you see that 6 volt drop. Also, could the 200 feet distance be slightly shorter? More than likely the gauge you bought is no more than and could measure no less than. Conductivity of wire is temperature dependent; usually rated at 70

It can't be magic... Its science
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Old 01-27-2016, 08:34 AM   #36
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Were never going to agree, to each his own, seen it, done it, its all good,,,,

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i'm not sure how you figure that. If that were true i could run 30 amps at 120 volts on a #10 wire 500 feet and still have acceptable voltage at the destination.

According to my calculation the voltage drop would be 35.4 volts so the final voltage would be 84.6 volts. No 120 volt device that i'm aware of would like that.

One should always consider voltage drop when running more than about 20' of wire.
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Old 01-27-2016, 08:55 AM   #37
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I thought a 3 a/c units are managed and don't run at once??? I just read a 15K btu pulls only 11Amps - running. Startup about 16/17. I don't think your EMS will see startup loads. You didn't say how many amps you are pulling when you see that 6 volt drop. Also, could the 200 feet distance be slightly shorter? More than likely the gauge you bought is no more than and could measure no less than. Conductivity of wire is temperature dependent; usually rated at 70

It can't be magic... Its science
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No, all three can run at once which was the case on our trip to FL where we met up. Man you guys got some heat down there! The management system only sheds one AC (or my electric HW element) if it senses low voltage. I had more than just the three AC's on when I checked voltage too. I can't remember the amps from the readout. A lot can disappear from the mind in a year when it's not that important to you...LOL.

On length, yep, it's about 196 feet. Bought 200 and had a couple feet leftover. And, that's only to the house. Another 20 feet or so to my breaker box from point of entry. THHN from outlet to house and 6/3 Romex from point of entry to breaker box. Oh and then another 50 feet of RV umbilical from the outlet to the RV. So, closer to 300 feet total of #6 plus all the trailer wiring it has to go through...

Now, here's some more magic that most people never see. The wiring supplied by Onan that runs from the genset to the J-box installed by XLR is tiny stranded wire that looks to be the size of lamp cord. It's commical to see it tied to the #6 in the J-box where it meets XLR's wiring. My last Onan 5500 in my previous hauler was the same. I'm guessing they get away with it because it's such a short run?
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Old 01-27-2016, 09:59 AM   #38
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The calculator produces typical values because the conductor values differ. The type of wire; the conduit, the connects; besides the advertised gauge can make a difference, but these are usually close. I don't doubt for a second what you said is your net voltage. Thanks for explaining about multiple a/c units. If its for me I might skimp on the gauge. The guy that wired up my menagerie if buildings used a voltage drop calculator and he has 39 years experience so; I figured it must be important. The experts say a maximum drop us 3%, but if I came up with 4% at the RV shed, I would do that and not be at all concerned.. it seldom is used and never stressed.

12awg will run 50amp load for 25 feet and stay under 3%
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Old 01-27-2016, 10:09 AM   #39
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I too had an experienced friend help with pulling the wire to my shed and RV outlet. He actually used his discount to get me the wire. Licensed electrician over 20 years and now works high voltage for Eversource for about 5 years, our big utility in the area. Man, his job scares me. You don't just get shocked due to a fail. You don't go home. I can't imagine working on high voltage never mind high voltage transmission and switching. 33-330k. Yikes!
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Old 01-27-2016, 10:10 AM   #40
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The calculator produces typical values because the conductor values differ. The type of wire; the conduit, the connects; besides the advertised gauge can make a difference, but these are usually close. I don't doubt for a second what you said is your net voltage. Thanks for explaining about multiple a/c units. If its for me I might skimp on the gauge. The guy that wired up my menagerie if buildings used a voltage drop calculator and he has 39 years experience so; I figured it must be important. The experts say a maximum drop us 3%, but if I came up with 4% at the RV shed, I would do that and not be at all concerned.. it seldom is used and never stressed.

12awg will run 50amp load for 25 feet and stay under 3%
Brings up another question. I keep seeing and hearing about 110/120 volt or 220/240 volt. It appears we say 120 (or 240) when referring to the voltage output at the entrance service panel. But, it seems most consumer electrical products refer to everything as 110/220.

Would that mean the minimum voltage for that particular device is 110/220? If so, using the 3% drop factor results in a 200 foot run losing 7.2 volts (120 line) or 14.4 volts 240. Either would result in adequate power for the end consumer when thinking about 110/220 (I think).
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