Low voltage to the 5ver.

[Pocketlake1]

Visiting a friend who was good enough to install a 30A outlet for our visit.  It shows 120v when little to no load but when I turn on a single AC unit it runs fine but the voltage level drops to about 105. Also can't start the microwave when AC unit is running. I suspect he undersized the wire. All connections tight. .  Will the low voltage damage the Dometic AC unit or do they build them tolerant enough for it not to be an issue?  I'm in Florida and praying the answer is don't worry about it cause it is REALLY hot but will live with not running the unit if it's possible the low voltage may damage it
Thanks for any insight

 

[tvman44]

I would not run mine with 105.

 

[kdbgoat]

What you suspect is probably correct. Do you know what size wire he used? How long is the run?

 

[SargeW]

Ken, I can tell you this. My Progressive Industries Surge Guard that is wired in my electrical bay WILL disconnect from power if the voltage drops below 105 volts.  This is to save the AC appliances from damage from trying to run on low voltage.  The damage may not be apparent right away, but damage to the AC units, microwave, household refer, and  TV's IS imminent.

Use great care when plugged into that outlet.

 

[Pocketlake1]

He is using what looks like 10g wire on about a 150 ft run. That's from a main panel to a secondary panel and then a short run from that to the outlet.  I've moved our refrig over to gas and stopped running the AC units.  Good news is we never turned on the tv.  My surge protector just gives an indication of low voltage but does not shut down.  Sure wish manufacturers for trailer appliances built in more methods for tolerance, or ability to automatically shut off before damage is done.  Hope this does not become an expensive lesson
Thanks, appreciate the insight

 

[kdbgoat]

10ga. is really too small for a run that length. You should run at least8 ga. Sorry, I'm sure that outlet is getting expensive.

 

[SargeW]

Remember that many of the appliances that are used in RV's are just residential appliances that are installed in the rig. TV's, micro's, toaster ovens, coffee makers, DVD and Blue Ray players, and the list goes on. Those appliances are designed to get a steady voltage within a certain range to operate normally. 

RV parks often have wildly fluctuating voltage, especially in the summers when everyone's AC's are running. So having a good surge guard that will protect your appliances is smart.  On some RV's,  an Inverter will power the rig with constant 120 power from a battery bank if power drops out.  That won't help the AC's though. 

 

[tvman44]

You need more than surge protection, you need power management that can shut down on wrong power.  #10 is too small for that long of a run.  You might check voltage at the main panel, most likely Ok there just the long run of #10 that is the problem.

 

[Gary RV_Wizard]

Yeah, 10 ga is too small for 150 ft and 30A. 

105v is about my lower limit for acceptable voltage (and my Surge Guard agrees!), but about the only thing at risk is the a/c compressor. Toasters, hair dryers, tvs and such won't much care, or simply won't run, if the voltage is too low. They aren't going up in smoke!

It's not surprising the micro won't start when the a/c and other stuff is running. 30A isn't a lot of power when you turn on things that gulp 10A-14A each. You need to educate yourself a bit on the power consumption of your various appliances. Some of them, like the fridge and water heater, cycle on/off via a thermostat, so you may be fine for awhile and then suddenly the breaker trips because multiple things cycled on at the same time.

Here are some charts showing typical power consumption:
https://www.steadypower.com/pages.php?pageid=133
http://www.rv-motorhome-answers.com/AC-Electricity.html

 

[Pocketlake1]

Gary, thanks and yes I am getting quite an education on power consumption and especially the effects of low voltage. Pretty obvious on what the items with the big draw include. Frankly did not give it much thought when he shared he had installed the outlet just for our visit, and he is a pretty capable guy,but that's what I get for assuming.  . Live and learn.
So far AC units seem fine and we are back home for the trip, but time will tell. Still have time on the warranty.  I was concerned about the fridge as well, but it's seems to be doing ok.
I will have a lot more awareness when checking into campgrounds in the future. Seems power is just  like Goldilocks, not too much, not too little, but just right
Thanks
Ken