It was a couple of years ago. I have brochures from them somewhere but
can't remember the names. The best one had real nice lawns trees and was
quiet but the water was really full of rust scale. The power was below
normal most of the time.

Absorbtion refrigerators use a resistive heating element when run on
AC.  While low voltage won't damage these frigs, they also may not
cool as well at low voltage because the wattage of the heating element
decreases as the square of the decreased voltage.  Ohm's Law.

P=E^2/R where P = watts, E = voltage, and R = resistance.

The power company only guarantees 120 volts +/- 10%.  Even a drop of
10% means a loss of 20% cooling.  My Dometic frig has a 49 ohm
element.  At the normal 120 volts, the output from the heating element
is 120^2/49, or 295 watts.  Drop the voltage down 10% or 108 volts,
the heating element puts out 108^2/49, or 238 watts.  That's a 20%
loss in wattage used to power the boiler in the frig.

That's why on a hot day with low voltages, I run my frig on propane
even though I'm hooked up.  Gotta keep those Red Dogs cold you know!
It's all about priorities.   :)

- Sandy

Ben, Thanks for the good answer (which as I read it is "it depends").

Probably the biggest risk I face is harming my Coleman AC with too low
a voltage, hence too much current. Are Coleman AC's thermally
protected?

Everything else I could ruin is fairly inexpensive hence can be its own
fuse.

As I write this I'm on 475' of #12 wire & 100' of #10 wire. My Coleman
13kbtu AC compressor won't start; the voltage drops to about 100. If I
can get the AC started with a soft-start kit, will it be harmed by
running at reduced voltage?

Dave

Actuallly, corrosion can reduce the amount current a wire is capable of
carrying. If the corrosion reduces the size of the wire from #12 to an
equivalent #14 AWG, it will not be able to carry the current of a #12 wire
to the load which see less than 120 VAC. In addition, if two #12 wires are
spiced but make poor contact, they cannot carry the full load of a #12 wire.
That's why you clean your battery terminals in your truck so the battery can
send enough current to the starter motor to turn and start the gas/diesel
engine.

dandodd
MS Electical Engineering

AL wire is not needfully a problem. Poorly installed it is
considerably more fault prone. Nick it and let water get in kiss that
section or short lowest spot goodbye. WITH real fun finding the almost
break as it becomes a series nonlinear current dependent resistor.
Loose connections not properly brushed and aloxed do similar.
The reverse holds true however. Properly installed AL with all
connections made to spec is the usual backbone of most utilities.
Nitpicking about alclad steel aside AL is the cost effective metal for
large utility scale work. YMMV but the economics are cruel masters.
I worry more about homemade plug adaptors being miswired. And the
adaptor using a 20/30 to simulate a 50.  Many older parks "upgraded"
by putting a 20/30 box on wiring barely adequate for 20. thence
someone plugs a 50- which is actually 50 amps PER LEG into such an
adapter thence plugs 3 electric heaters in -2 on high and one on low
...then wonders why a 1750 W coffeemaker or griddle pops the
breakers<AsIf you've never seen this eh?>

The simple FAQ level reasons are more of understandings.
That perceived 20\30 box =50 amps is NOT often intended as such.
In that mythical kingdom of perfect maybe. Not here. Here's Why/how.
99% of campers in average comparisons split between either 20 or 30
amp service.
50 amp rigs still by sheer mass of older rigs are a minority.
The splits between 30 to 20 is more arguable a zone but still tilts to
30 as a common denominator.

SO that caused many installs of a box and wiring rated for the 30 amp
full load . The 20 was a courtesy for those with older rigs or perhaps
an outside coffee pot etc on a picnic table. Never really designed to
be BOTH sides full loaded. Because most parks allow one camper per
site.
That presumes an either or on a max 30 site. So when someone starts on
a few sites pushing the envelope....
Often one will see 3~5 orange cords extending to vacant sites running
each one 1500 w milk or cube heater to heat a screen room etc. It
takes only a few times of that kind doing so for campground owners to
get fed up and begin locking boxes or posting "no electric heat"
signs... Someday I may post the story of the campground we stayed at
that had more "no electric heat!!!" signs than disney has pics of the
mouse!.
Electric heat sadly is not the end of all power issues. AC can be
worse in summer      

Because many folks with 50 amp rigs often use a lighter 30 amp cord
with adaptors. Either from 50>30>50 or at 30 to the rig's cord thence
the 30>50 being hanging from the plug of the rig arcing softly in the
dew.  OR the even more WtF inducing 20 amp socket plugged with a 20 to
30 thence into that 30 to 50 trying to start 2 roof airs.... *POP* the
breaker and scratching of head may bring dim recall of 50 is larger
than 20- and that "50" is actually a 100 if single leg fed!

All this had been believed beaten to a thin red smear in past posts.
But it still warrants doing some research to enlighten the ones who
missed the first go rounds of this . Last month a camper came in with
a 50 amp plug wired "to work fine in TX" He complained he had only 110
from his 30 to 50  adaptor and popped the breaker if plugged into the
50 outlet direct . Had him open all breakers and ...ZERO ohms between
the 2 hots of that 50 plug end  of his  hardwired cord .Yep, a 3 wire
cord with a 4 wire plug.

White and green ok but black tied to both hots.

Maybe the park he last stayed at was wired that way . I suspect he may
have some issues wherever else he stays . 110 nominal is all one gets
on a standard 3 wire rv socket... Now some cringemaking setups using
dryer plugs are out there but rare.

Autoformers are an interesting application poorly understood and often
deadly. They are NOT an isolation per se but merely a buck or boost
device. Robbing peter to pay paul is not strictly true but it still
does hold that taking more for one rig will decrease ampacity reserve
for the others in that path. The ferroresonant self regulating ones
can be VERY expen$ive and heavy. Oh, they work after a fashion but are
a hackaround rather than a real good fix for long stays.
Still they have uses if you have no other choice where to stay and are
willing to educate yourself on what they can and cannot do. Buyer be
careful as in all things.  The summary statement is most American
electronics are supposedly made to be stable/safe from 105~129 vac    

Oren Beck

www.campdownunder.com

"But remember, please, the Law by which we live,
   We are not built to comprehend a lie,
We can neither love nor pity nor forgive,
   If you make a slip in handling us you die!"

The Secret of the Machines:Rudyard Kipling