This weekend I went to a campground that I have never been to before. After plugging in my 30 amp plug into the outlet and turning on the Air Conditioner I took a glance at my cheap voltage gauge that I keep in a outlet near my bed. It read very low. I also notice that the AC was making a different sound then usual. I checked to make sure that everything was plugged in good and tight. Then I felt the breaker for the 30 amp plug and it felt a little warm. So I shut everything down and dug out my 50 to 30 amp dog bone adapter. Once I plugged in with that I had great voltage and the AC sounded much, much, better. I learned these tips by reading on this message board and I wanted to thank the members here for teaching me these types of things. Thank You

Good for you but if you really want to protect your trailer's electrical system against the damage excessively low voltage can do invest in an EMS that will disconnect from power automatically once source voltage drops to a certain preset level. If losing power entirely isn't something you can live with then an alternative solution is a voltage regulator such as a Hughes Autoformer that will boost low voltage so it is acceptable. Either is a much better solution than just plugging in and hoping for the best.

and invest in a multi meter and check voltage/polarity BEFORE hooking up.

rk911 wrote:and invest in a multi meter and check voltage/polarity BEFORE hooking up.Really no need if you've got an EMS as it will do this for you automatically when you plug in and won't pass power on to the rig if it does detect an issue.

It's handy also to be able to monitor incoming source voltage throughout your stay, just as I do with this Kill-a-Watt meter plugged into a galley receptacle.

I built this dongle so I could check the campsite source supply for adequate voltage and correct wiring before plugging in but with a Progressive EMS protecting the rig using it was kinda pointless as the EMS does all these checks anyway so I no longer bother with it.

A Thank You to the members about low voltage | Good Sam Community

edatlanta
Explorer
Jun 27, 2018
My PT50X EMS did it again. Night before last my PT50X shut me down due to an open ground. After the 2 1/2 minute delay it passed power to my rig again only to shut me down again a couple of hours later. While it was a terribly uncomfortable night without a/c I did it. The park manager had an electrician on site by 9:00am the next morning and he replaced the 50a breaker, socket, and jumpers. If the problem still exists it most likely isn't in my pedestal. There was no open ground when he arrived, but he replaced the parts anyway which was ok with me.

Now all is well.

I won't plug in anywhere anytime without my PT50X.
CavemanCharlie
Explorer III
Jun 19, 2018
You know. Back in the day when they first came out with microwaves it was very important for them to have the correct polarity. But, these days what in my old TT would really be hurt by reversed polarity.

A lot of older homes in my area might still not be correct. My home included. They put in a dedicated circuit when they installed the microwave in the kitchen of my home. Heck, I don't even have grounded plugs except for the microwave one and 2 others that I have had installed. One in the bathroom and one for the TV / Computer.
SoundGuy
Explorer
Jun 19, 2018
time2roll wrote:
If you have a 50 amp RV you need a custom adapter that checks both.

EMS protection is always best.

Exactly what I already said earlier. ;)
pianotuna
Nomad III
Jun 19, 2018
Checking 50 amp requires measuring voltage under load on both legs. That is easy enough to do if you have a break out box designed to allow you to draw power from either leg (one at a time of course).

Checking voltage without a load is not best practise on either 30 or 50 amp.
time2roll
Nomad
Jun 19, 2018
For a 30 amp RV the polarity check works fine on 50 amp with adapter. Although extremely rare to find 50 amp service with bad polarity.

No need to check both sides as the adapter and 30 amp RV only connects to one side.

If you have a 50 amp RV you need a custom adapter that checks both.

EMS protection is always best.
SoundGuy
Explorer
Jun 19, 2018
Lenny K wrote:
Does this setup work for 50 amp if you use a 50 amp adapter?

SoundGuy wrote:
50 amp RV service is actually 100 amp service consisting of 50 amps across each of 2 legs so obviously if you wanted to check both legs you'd have to use 2 monitors. The simpler and better solution for those who have a rig wired with 50 amp main service is to invest in a 50 amp EMS which is designed to check & continuously monitor both legs of that 50 amp service.

DrewE wrote:
Basically correct, but it's inaccurate to call it a 100A service. It is a 50A 120V/240V split phase service. None of the wires or connections ever have 100A flowing, and you don't need wire sized to carry 100A, and you cannot power a single 100A 120V device should you happen to have such a beast. You can use up to 50A at 240V, or have two legs of 50A at 120V, but not a single leg at 100A.

No need to blow this out of proportion, I never said anything about 100 amp flowing through any single connection nor powering a single 100A 120v device. :S I merely responded to the question as to whether polarity checkers or type of dongle I built for myself for use with 30 amp campsite service is suitable for also checking 50 amp campsite service, the answer being no because 50 amp RV service is across 2 legs whereas 30 amp service is across a single leg ... but of course you already know that. :R
DrewE
Explorer II
Jun 19, 2018
SoundGuy wrote:
Lenny K wrote:
Does this setup work for 50 amp if you use a 50 amp adapter?

50 amp RV service is actually 100 amp service consisting of 50 amps across each of 2 legs so obviously if you wanted to check both legs you'd have to use 2 monitors. The simpler and better solution for those who have a rig wired with 50 amp main service is to invest in a 50 amp EMS which is designed to check & continuously monitor both legs of that 50 amp service.

Basically correct, but it's inaccurate to call it a 100A service. It is a 50A 120V/240V split phase service. None of the wires or connections ever have 100A flowing, and you don't need wire sized to carry 100A, and you cannot power a single 100A 120V device should you happen to have such a beast. You can use up to 50A at 240V, or have two legs of 50A at 120V, but not a single leg at 100A.

Similarly, a semi tractor pulling dual 28' trailers is not a truck with a 56' trailer. The two are far from equivalent if you have some 35' long pipes to haul.
SoundGuy
Explorer
Jun 19, 2018
Lenny K wrote:
Does this setup work for 50 amp if you use a 50 amp adapter?

50 amp RV service is actually 100 amp service consisting of 50 amps across each of 2 legs so obviously if you wanted to check both legs you'd have to use 2 monitors. The simpler and better solution for those who have a rig wired with 50 amp main service is to invest in a 50 amp EMS which is designed to check & continuously monitor both legs of that 50 amp service.
Lenny_K
Explorer
Jun 19, 2018
SoundGuy wrote:
pasusan wrote:
This is what I use along with this.

and

You can use it at the pedestal with the adapter and use it inside without.

Sure you can BUT the downside is when plugged into a 30 amp campsite power post the meter will be upside down :M , ergo the reason I built my own dongle that allows that same Prime Products meter to sit correctly when plugged into the campsite power post. :B

Does this setup work for 50 amp if you use a 50 amp adapter?
SoundGuy
Explorer
Jun 19, 2018
pasusan wrote:
This is what I use along with this.

and

You can use it at the pedestal with the adapter and use it inside without.

Sure you can BUT the downside is when plugged into a 30 amp campsite power post the meter will be upside down :M , ergo the reason I built my own dongle that allows that same Prime Products meter to sit correctly when plugged into the campsite power post. :B

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