RV electric power, half not working

myredracer wrote:
With all due respect, as an electrical engineer, I have to say that your electrician does not know what he is talking about...

Well, I know that I definitely don't know what I'm talking about when it comes to electrical systems... My son will be starting the EE program at university this fall, maybe some day I can get him to explain it all to me :).

myredracer wrote:
You haven't stated if you used a 30 to 15 amp adapter at the end of your 30 amp cord to plug into an ordinary 15 amp recept. or extension cord, or if you plugged into a welder or dryer receptacle or made up a new dedicated receptacle to plug into.

I'm plugging in to a dedicated 20A outlet in my garage (installed for my small 120V/140A welder), via 20A extension cord and 30/15 adapter. I have a Honda 2000 w/30A twist lock outlet and an adapter to use that outlet, the AC seems to run well on that, but I haven't measured any of the outlets while on the generator.

Already had on my lengthy to-do list to get a 220V outlet installed in the garage for a future bigger welder, this experience has me thinking adding a 30A RV outlet at the same time would be a good idea.

There are two outlets in the TT that do work. The GFCI in the bathroom and the outlet that the microwave plugs in to. I have measured both of those at they are at 120V to 122V with shore power plugged in to the 20A outlet in the garage. But, when I run the AC, the voltage on both of them drops to 106V to 108V. I think I can deduce from that, that the current from the garage outlet is just barely adequate to run a single device. Once I get this problem figured out/fixed, I don't think I'll want to try running the fridge on AC current and anything else at the same time - until/if I get a 30A outlet to plug in to.

Just hoping that A) I can find an obvious problem that will be easily fixed by inspecting outlet connections after removing them from the walls and that B) no damage has already been done to AC powered devices in the TT.

Wish my son was a couple/few years farther along with his education :).

- Coyote

With all due respect, as an electrical engineer, I have to say that your electrician does not know what he is talking about in regards to either the open neutral or the receptacle quality.

The receptacles are used exclusively throughout the RV and manufactured home industry. They carry a safety certification. They are completely safe if properly installed and the wires are terminated correctly. If someone is not used to them and does not know how to properly terminate the wires on them, I could see them being frustrated with them. They're perfectly safe and they are very easy to install if you know what to do. In fact, they're easier to install than one in a house because there's no outlet box and wire count to deal with.

The only thing I don't like about these receptacles is that the batt insulation in the walls usually gets compromised. The wires and devices push the insulation towards the outside wall and thus leaves a void in the wall and compressed insulation, both resulting in substantially reduced R-value in those places.

The only way an open neutral could be causing your problem is if it is in your house panel. Then you'd have problems in your house as well. An open neutral inside your RV will not cause the voltage to rise like that. In your RV, an open neutral will result in lower voltage, and right down to zero. Here's a good read: RV open neutral info.

As I said earlier, if you have 190 volts inside your RV, then anything plugged in and "on" will be damaged. Replacing and repairing these is not cheap, as in many hundreds of $$. Some info. on what happens when you plug into 220 volts on these FR threads: Fried components inside RV Plugged into wrong voltage

You haven't stated if you used a 30 to 15 amp adapter at the end of your 30 amp cord to plug into an ordinary 15 amp recept. or extension cord, or if you plugged into a welder or dryer receptacle or made up a new dedicated receptacle to plug into. Many people, including some electricians have made the mistake of modifying a welder or dryer outlet to run a 30 amp RV service and then the damage happens... I've read about some electricians who have wired up a correct 30 amp RV receptacle (TT_30R) to 220 volts assuming that all RVs run on 220 volts.

I hope you get to the bottom of this and hopefully don't have much or any damage to deal with.

Had a chance to chat up a master electrician about this. As has already been advised in this thread, he thinks it is most likely a bad connection on the back of one of the outlets. Said the high voltage indicated a bad neutral was the likely culprit. Said it happens fairly often with RV outlets because of the way the wires are connected. He did not share any high regard for the RV outlets, said some extremely uncomplimentary things about them. About the kindest comment he made was that they were designed by the accounting department and approved by the legal department.

Been just too busy to mess with this, hoping to find some time over the coming weekend. Am simply going to start pulling all the outlets off the walls and physically inspecting, one at a time.

- Coyote

The converter does not affect the incoming AC. It serves as a combination battery charger and DC supply for any DC loads.

What have you got your camper plugged into? An ordinary 120 volt receptacle in the house or is it a welder or dryer outlet circuit? Better check the voltage where you have it plugged into.

As I said, if the voltage is that high, you've damaged things inside your camper. Don't turn on the AC unit to see if that is working.

rlhay wrote:
May or may not make a difference but the red cable on your multi meter should go in the smaller slot in the receptacle, this is the black hot wire, can't tell if it is correct in the picture. Sometimes if cables are backwards this will give false voltage readings.

Since I didn't know if it mattered, I tried both ways. When the leads are reversed, the reading would be -191 (minus). Tried it in the house the same way, got 117V. For that matter, the only GFCI I can find in the TT measured 107V.

The others only measure 191V some of the time though. Usually, they measured zero. All the 12V stuff "seems" fine. Batteries get charged, pump and furnace work etc.

Does the converter do anything with the AC power coming in, or just pass it through and distribute?

Stumped...

- Coyote

UTCoyote, if that really is 190 volts in a unit that has a 30 amp panel, then there is something seriously wrong somewhere. If that high, then anything that is always connected to 120 volts like converter, fridge, microwave, etc. will be permanently damaged as would an AC unit if turned on. I would say take your meter inside your house and see what it reads there.

If you had a 50 amp service, an open neutral can cause a high voltage like that but in a 120 volt 30 amp service you'd read zero.

I made a bad statement when I said the rv receptacles look cheap, I stand corrected. Looks like the receptacles are well made if installed correctly, myredracer thanks for the link. I agree using wire nuts outside of an electrical box in not a good practice. I used them temporarily to troubleshoot the problem then turned power off when I was done. I plan to replace the receptacle this week.

May or may not make a difference but the red cable on your multi meter should go in the smaller slot in the receptacle, this is the black hot wire, can't tell if it is correct in the picture. Sometimes if cables are backwards this will give false voltage readings. Put the red cable in the small slot, black cable in the larger slot and check voltage. Then move the black cable to the round hole in the receptacle, this is the green ground wire, and check voltage. Something is bad wrong if you get 190v.

myredracer wrote:
190 volts? Did you mean 109 or do you have a 50 amp panel? If 50 amps, that could mean a problem at the panel but don't know how you measured that.

No, I meant 190V. And actually, it was 191V, to be more precise. Measured with a meter in the outlet. Panel is only 30 amp I believe.









Note - I'm electrically challenged. I've no idea what I'm doing. Just kind of stumbling around blindly with it hoping to find an acorn...

- Coyote

190 volts? Did you mean 109 or do you have a 50 amp panel? If 50 amps, that could mean a problem at the panel but don't know how you measured that.