Voltage and polarity

Yo,
I have run into a review of a campsite where they mention that they found some pedestals with low voltage on some and reversed polarity on others I plan on getting the test gauges to do this. The questions are:
1. What voltage is too low to run AC, TV etc?
2. What happens if there is a severe voltage drop while connected and running?
3. If I find reversed polarity, what do I do about it? What are the ramifications if I connect to a reversed polarity outlet?
Anyone run into these problems?
Thanks all.

 

Get a campsite near to the main electrical distribution box the voltage will always be higher there the longer the run the lower the voltage.

Get a quality camping surge protector should trip if the voltage gets to low before any damage occurs

You could make a short cord with a connector that has the wires switched to change the polarity back

But i really think these problems are rare and would not lose any sleep over them get a shore power surge protector that should cover 99% of any problems

 

Ken,

That is a great question actually. One I find myself contending with from time to time.

First lets talk reverse polarity. It is indeed true that you will run into campsites with this, campgrounds often have homespun wiring you know. Your trailer runs all of it's AC power through a GFCI circuit (ground fault protected). We do this because you are standing on bare ground so you need to always be ground fault protected. GFCI is fussy circuit however. It has to have the wiring correct feeding it or it just won't work. A reversed polarity for instance will cause you to not have power at the outlets (or any of the AC in the trailer). It doesn't "trip" it, it just won't have power. Hitting the reset button does not do anything for you in the case. You just won't have power unless you did something like Tony's circuit reverser cord.

Low voltage? This does happen. For the AC power about the only danger of this is you could stress your battery charger or air conditioner if running them with too low a voltage. It would have to be really low to be a big concern however. The air conditioning will handle down to probably close to 100vac.

The TV should not be affected since it is running completely off of the battery.

Cary



What

 

Cary,
Thanks.
I will look into getting the circuit reverser cord that Tony mentions.

On another note, is there any plan in the future to go to a 30 amp system?
I was looking at a single serving K-cup coffee maker and wondering what the best way of determining possible overload problems. I would try to be conscious of the air conditioning not being turned on etc.
Would it be best to convert the appliance watts to amps?
But what appliance amperage amount do you think would be close to tripping a breaker?
Don't you love these questions from a liberal arts customer?
Thanks,

 

30amp?

Um, no.

Cary

 

Surge protectors are not line conditioners. They do not protect from under voltage.

 

does this mean there is nothing we can do about the issue, or are there cheap "line conditioners" that will help?

 

Cheap line conditioners? No. Especially not one that would resolve a voltage sag condition. This would likely require a UPS system.

Cary

 

I like it when the solution is, "there's nothing you can do about it"

!!

I'm serious!

 

Cary is right, line conditioners will not take care of sags in voltage. Most consumer type line conditioners utilize MOV (Metal Oxide Varistors) which will clamp a spike or voltage transient to a certain level so damage will not occur to the device plugged into it. Industrial line conditioners will add filters which will take care of electrical noise which can wreak havoc with industrial equipment. The most critical appliance in your teardrop would be the television, however this is connected to the battery which isolates it from the 120 volt shore power.

A simple formula to remember relative to electrical loading is Watts/Volts=Amps

If you have a 1500 Watt space heater running and the voltage is 120 Volts your Amps wil be 12.5 Amps. If your shore power drops to 100 Volts, then your Amps will increase to 15 Amps. Most plug in electrical will state the watts somewhere on the unit.

In the above example if you have the space heater running and you decide to plug in your 1000 Watt coffee maker you will trip a breaker in your teardrop but not at the campsite pedestal feeding your teardrop since most of those units are rated at 30 Amps or above.
Leo

 

A simple formula to remember relative to electrical loading is Watts/Volts=Amps

If you have a 1500 Watt space heater running and the voltage is 120 Volts your Amps wil be 12.5 Amps. If your shore power drops to 100 Volts, then your Amps will increase to 15 Amps. Most plug in electrical will state the watts somewhere on the unit.


Leo[/QUOTE]

The 1500 watt space heater is rated for that power at 120 volts. When you sag to 100 volts the current decreases and so does the watts. I=E/R , R=E/I , P=EI , and substituting E/R for I then P=EE/R. 1500/120 = 12.5 amps - solve for R= 120/12.5 gives us 9.6 ohms. At 100 volts P=(100)(100)/9.6 gives us 1042 watts. The space heater will simply put out less heat because it is a resistive device. Other devices - such as your air conditioner may have some starting issues due to the lower voltages.

 

I’ve only had to use it a couple of times, but I always carry one of these 30a to 15a adapters.
https://www.amazon.com/Camco-PowerGrip-Durable-Electrical-Adapter/dp/B00192QB3I/

The 30a receptacle on a shore power post is also 110v. If the 15a service isn’t working for whatever reason, a quick switch to the 30a has always worked.

 

Great suggestion... I've needed one once or twice as well.

I also carry a 110 receiptical tester -- park power pols are notoriously poorly wired. I stayed at once last summer that actually sparked when I plugged in. And yes, the breaker was turned off on the 30amp circuit :O

As for line conditioners, anything that will fix a 'sagging' voltage, those are commonly sold as "Autoformers", these are common in the 'big rig' world, and if I had a $400,000 rig I'd indeed have one built directly into the electrical system. Sadly I am told a lot of places are forbidding their use...probably mostly out of ignorance.

I've never seen one for 15amp

I've got a 50amp version sitting right next to me and I know I used it everywhere I went. The line voltages drop DANGEROUSLY low in most parks on summer days. This is especially true for old parks. When these were built, the electrical system was set up for a few lights in a tent. In the past 30 years RV's have gotten progressively larger, its getting to where 50 amps is a base model with 2 ac's, a microwave, and a fridge, not to mention hair dryers and strings of party lights....

 

I haven't had to use mine yet, but I bought the same adapter from CI when I bought the trailer. A handy little item to have.

 

We have that exact same one and only had to use it once this summer. But I was grateful I bought it “just in case.”

 

I routinely plug into 30a because the 15a’s are often worn and wobbly.