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Old 08-20-2012, 09:52 PM   #21
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Quote:
Originally Posted by herk7769

What gauge?
I doubt it would be 8 gauge (40 amp) rubber shielded 3 wire (Black, White, Green).
It's a 30 amp and it was the same gauge as the stock power cord with camper I did searching when I needed 50 feet for a trip.
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Old 08-21-2012, 07:14 AM   #22
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It's a 30 amp and it was the same gauge as the stock power cord with camper I did searching when I needed 50 feet for a trip.
That would be 10 gauge (30 amp). You most likely will only be able to pull about 20 amps through 100 feet before the voltage drop in that narrow a pipe will cause air conditioner damage.

Still, a buck a foot is pretty cheap. Have you seen the cost of copper lately?
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Old 08-21-2012, 07:49 AM   #23
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Originally Posted by herk7769 View Post
That would be 10 gauge (30 amp). You most likely will only be able to pull about 20 amps through 100 feet before the voltage drop in that narrow a pipe will cause air conditioner damage.

Still, a buck a foot is pretty cheap. Have you seen the cost of copper lately?
You are correct, herk.
I just ran through the numbers and even an 8 guage 100 foot cord would have a drop of 4.7 volts at 30 amps. So a 10 guage would obviously not be up to the task.
I'd better go have a look at my cords!
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Old 08-26-2012, 07:34 PM   #24
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Ok, I have to go 120 feet. Do I need to go with 6 gauge?
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Old 08-26-2012, 08:28 PM   #25
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Ok, I have to go 120 feet. Do I need to go with 6 gauge?
Is that 120 PLUS the 30 foot OEM cord? If so you would be OK with 8 GA I think unless you plan on doing something silly like trying to use both the AC and the water heater on electric at the same time. 5 volts may seem like a lot, but it is not so bad.

It IS horrible when it STARTS OUT at 110 or 105 (instead of 120 like it is supposed to) and drops 5 volts though.
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Old 08-26-2012, 09:33 PM   #26
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No, it's 120 feet total from the pod to the camper. I would be careful about how many amps I would use, just don't want to fry a cord. Wasn't sure if 8 gauge would be enough to go that far. Thanks for the response.
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Old 08-26-2012, 09:57 PM   #27
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rsn, you wouldn't have to worry about frying the cord, as the resistance and resulting heat would be spread over the full length of it. It is the appliances you need to watch,, as the voltage drop is hard on motors and such. At 120 feet, an 8 guage would probably do. Remember, the above calculations are at full load. So I suppose even a 10 guage would work if you were very careful. But it would be good to have a voltmeter just in case. Knowledge is power.
Does anyone know how many amps a 15,000 btu air cond pulls at startup?
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Old 08-26-2012, 10:31 PM   #28
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rsn, you wouldn't have to worry about frying the cord, as the resistance and resulting heat would be spread over the full length of it. It is the appliances you need to watch,, as the voltage drop is hard on motors and such. At 120 feet, an 8 guage would probably do. Remember, the above calculations are at full load. So I suppose even a 10 guage would work if you were very careful. But it would be good to have a voltmeter just in case. Knowledge is power.
Does anyone know how many amps a 15,000 btu air cond pulls at startup?
The starting amperage is listed in the specifications as locked rotor amps or LRA. The ones I've found are listed at around 66 amps.
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Old 08-26-2012, 10:38 PM   #29
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The starting amperage is listed in the specifications as locked rotor amps or LRA. The ones I've found are listed at around 66 amps.
This is true, but the amps are applied in seconds. It will be well below those to the "running amps" "normally" before the breaker can heat up enough to open.

It is the low voltage that causes high "long term" amps; enough to pop breakers.

The Autotransformer is made to fix this problem.
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Old 08-26-2012, 10:52 PM   #30
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Ok herk, you have my attention. This "autotransformer", could you explain how it helps? I know I could probably "google" it, but I'd like a more personal angle, if you have the time to explain it. Thanks.
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Old 08-27-2012, 06:25 AM   #31
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Ok herk, you have my attention. This "autotransformer", could you explain how it helps? I know I could probably "google" it, but I'd like a more personal angle, if you have the time to explain it. Thanks.
http://www.forestriverforums.com/for...ers-26202.html

Is my review of the one made by Franks Electronics.


http://www.forestriverforums.com/for...g-26268-2.html

Power problems last July at a KOA. Voltage at the Pole and inside after being boosted.
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Old 08-27-2012, 06:28 PM   #32
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Please ignore my ignorance, but as far as voltage drop if I only use 20 amps instead of 30 amps do I need to worry about voltage drop on a 120 ft cord?
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Old 08-27-2012, 06:32 PM   #33
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Please ignore my ignorance, but as far as voltage drop if I only use 20 amps instead of 30 amps do I need to worry about voltage drop on a 120 ft cord?
if you are plugged into 20 amps which most likely you are not ..... 20 amp receptacle is different than a normal household 15 amp altho they look the same . Almost all household receptacles are 15 amp

If that in fact is what you mean then yes you should be concerned.


now if you meant only using 20 amps from a 30 amp receptacle then you'd have very little left over for extras IE 5 amp loss
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Old 08-27-2012, 06:44 PM   #34
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Voltage drop is a function of current, wire size and material, temperature, and length of run.

All things being equal; less current means less voltage drop. However, all things are never equal. The closer to the max rated current you get the more heat is generated and the higher the resistance of the run which increases the rate of heat generation.

Using a wire rated for 30 amps and drawing just 20 will reduce the effective voltage loss by 33%. So, if the voltage drop was going to be 6 volts at 30 amps it will be 4 volts at 20, for example.
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Old 08-27-2012, 07:04 PM   #35
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Great, Thanks that answers my question! My plan is to use 125 ft 6 gauge wire. I have 30 amp service but don't plan on ever using more then 20 amps at a time.
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Old 08-27-2012, 07:07 PM   #36
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http://www.forestriverforums.com/for...aws-17300.html

just an fyi for usage !
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Old 08-27-2012, 08:20 PM   #37
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Lou, I get the auto transformer and the benefits of it. I cant afford it now but wondering do you use it when connected to your generator? I know you have a nice generator but with some of the non inverter sets out there would this still protect from a poor power supply? If you do use it with the gen set is there much added load with the auto transformer winding?
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Old 08-27-2012, 08:34 PM   #38
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My generator will hold 120VAC with the air conditioner running provided I am not in ECO mode. I installed a hard start capacitor and have not checked it yet to see if ECO will start it without tripping the generator off line.

I have a Yamaha 3000iSeB Yamaha Inverter EF3000iSE/B Home, information

It will provide 3000 watts steady with a 500 watt battery boost when needed.
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Old 08-27-2012, 09:01 PM   #39
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Lou - I was not questioning your set up but a question in general regarding the auto transformer(great idea). Is it something that would benefit someone using a power quality starved generator? Back to original thread bigger is better when distance is involved with wire size. I would not worry about heating up a overloaded cable in free air as I would damaging expensive equipment with the low voltage.
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Old 08-27-2012, 10:32 PM   #40
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Lou - I was not questioning your set up but a question in general regarding the auto transformer(great idea). Is it something that would benefit someone using a power quality starved generator? Back to original thread bigger is better when distance is involved with wire size. I would not worry about heating up a overloaded cable in free air as I would damaging expensive equipment with the low voltage.
Wally
What I was trying to say was as the wire heats up, the resistance increases and the voltage drop is greater for the same amps.

Since it uses amps to create volts, an autotransformer will work just fine to stabilize and condition the voltage coming from your generator at the expense of available amperage. So if your generator is putting out plenty of amps, but the voltage regulator has voltage swings or low voltage, then it will help you. If you are under amp'ed AND under volts it will actually hurt you by tripping the generator off line trying to ramp up the volts.
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