No power to passenger side outlets

[Edward Buker]

John,

I described a full test of the board. Your problem is either the line in wires do not have 120V on each leg with the coach plugged in, which would mean cord, plug, or connections before the transfer switch are at fault. The other possibility is that one of the two legs of the 120V is not being transferred through the relays to the load terminals in which case the board is defective. This board is just a big switch using relay contacts that either connects the genset or the 120V line in to the load terminals. The circuit board watches for genset voltage and when it sees it, then it automatically flips the proper relays and connects the genset, after a delay that allows the genset to stabilize.

The relays look pretty small to me and I would not be surprised if the board was the issue. Most of the replacement transfer switches will be housed in a metal box.

Later Ed

[John Padmore]

O,K, I haven't had the opportunity today to test anything due to heavy rain.
Previously I tested the 30/50 adaptor and had 120 on each side of the plug coming from shore power, so I am ASSUMING that the shore power cord up to where the 30/50 dogbone is ok. I suppose I can test the cord on the male side where it plugs into the coach?
I will get in the basement (groaning loudly) tomorrow and do the testing tomorrow.
 The relays look to be of normal size, and the current switch is housed in a metal box.
If the board is bad I guess a new switch is in order?......thanks.

John

[Edward Buker]

John,

The only reason to go back and test in the cord direction is if one of the two line in legs at the Transfer switch board does not have 120V with the coach plugged in. Otherwise you are testing just at the board.

I mention the size of the relay only because the brand of transfer switch in my coach used larger open GE relays and that is what I was used to seeing while poking around in there. Yours have to be rated for the proper current so it is just an observation John. Take your time, when the rain stops you will get to it....

Later Ed

[John Padmore]

OK Ed, I was able to test the wiring according to your instructions, and I believe I actually understand this switch now.
Here are the results:
Generator running = 120v on each terminal.
Load wires = 120v on each leg.

Gen off, coach plugged in =120v on white/red but white/black = zero
Load wires = 120v on white/black bur white/red = zero

Now, as I write this I am thinking of  what I have done to the coach recently and I think I may have found the problem.
I recently had the water service bay apart to fix a plumbing problem and I had to take apart the power receptacle to do so. I had a bit of a problem getting the wires back into the connector because they were so short.
Is it possible one of those wires came off as I reinstalled it and that is my problem?
I don't really want to try to tackle that one again if I don't have to, but I think it may be the culprit......thanks!


John

[Edward Buker]

John,

Good job on the measurements and understanding how this all works now, you may be an RV electrician yet.....

Somewhere between the power source and the transfer switch you are not connected on one of the hot lead sides. Good news is that the transfer switch looks to be fine. When you say you had to take apart the power receptacle, I do not know exactly what the function of that receptacle serves. If it is the one that the main power cord gets connected to coach wiring in, then by all means that could be the problem. Short leads and wire nuts are notorious for having issues if they are not tight or the wire is not fully inserted. They should be tight enough to twist the wires together and as a precaution then the wire and wire nut taped together all together with electrical tape so they cannot loosen up. If you are talking about a standard 120V outlet then that is not your problem.

If you can gain access to where the power cord is coupled to coach wiring in a junction box, that is where I would go next. If you get 120V on each leg of the main power cord then your problem is beyond that point. If not it is the power source, adapters, the cord, or the plug. Keep us posted, hopefully you are almost there.

Later Ed

[John Padmore]

Ed, thanks for the vote of confidence I appreciate it!

Yes, I was talking about where the power cord plugs in to the coach - the main power line.
I assume the other end of this wire ends at the transfer switch?
I am wondering if I can replace the wire with a longer one, just tape the end to the old one when I pull it out....what do you think?  Thanks.....

John

[Edward Buker]

John,

Usually the main power cord feeds the transfer switch and the output of that goes to the main breaker in your AC breaker panel. Sounds like you know what your problem is.

Sometimes you can gain some wire from outside of the junction box depending on how the cable was run. Disconnect the connections and loosen the clamp on the wire that can be rerouted a bit and pull more into the box. Mark the wire with a sharpie just inside the clamp location then pull the wire out of the box and trim the covering off back to your sharpie mark. That frees up the individual wires and will give you more slack hopefully. Take your time and rewire nut and tape each connection and work them back into the box. You can choose either wire to do this on. If you have no spare wire then for the lead you are having trouble with you can make a short jumper using a piece of the same wire gauge and two wire nuts to connect the existing wires through the jumper. You need to have enough space in the box to push all this back in and put the cover on. Either of these methods would be fine, which ever looks like the easiest cure. Take a photo if you get a chance, it helps us all learn and visualize these problems. Be sure and check that it all is working before buttoning everything up. This is probably a pain to work on but it is nice that you are looking at a $2 fix and for a motorhome problem that is always good news....

Later Ed

[John Padmore]

Ed, I found that one of the wires was loose and pulled out of the 50 amp receptacle pretty easily. I went to the big box store and bought 12" of each size wire to extend them.  I couldn't get wire nuts on them without taking the whole water panel apart again so I decided to solder them together. I was able to do this and put everything back together. Now I have 120v at the passenger side outlets (which was my original problem). I did not check the transfer switch since I had power to the receptacles.

Now, the extension cord that I have been using to plug the coach into the garage is getting hot at the plug end, and it never did that before. After a few minutes the house breaker pops. That makes me nervous. My question is:

Did I screw something up by soldering those wires together (to much resistance?) or do you think since I never had both legs of the 50 amp circuit working properly it never tripped the breaker. I have a 15 amp cord plugged into the 50 amp cord going to the coach.. Not much "on" in the coach....a 110 volt fan and whatever runs from the inverter. What do you think? Thanks.....

John

[Edward Buker]

John,

You may have a way to read current in the coach to see what the AC load is. If your hot water is heated with an electric element be sure that is off. You can kill the frig or put it on propane for a bit. The most likely thing is the inverter is charging the batteries and pulling more current than your breaker and cord can handle. I would start the generator and let it run half an hour or more with the inverter on to bring the batteries up and then when you shut it down let it flip over to the power cord and the 20 amp breaker and see if things are now O.K.  The solder joints should be fine as long as they have been soldered properly and it should be less resistance than using wire nuts. The fact that you are pulling more current, is just that you have more load, and not an issue with the solder joint repair. See if you can figure out what is pulling the load in the coach, it has to be exceeding 20 amps total to kick the breaker.

Later Ed

[Roy Warren Co-Admin]

John,
Many times when utilizing a long extension cord from a garage outlet that is also a ground fault outlet, the breaker will trip if the load nears the maximum amount.  It doesn't always need to exceed the 20 amps.  Make sure the outlet you use is not a ground fault outlet and you may have a little more luck.
Roy Warren

[John Padmore]

Ed, I started the generator and the inverter panel read:
DC Volts = 13.5 - 14
DC Amps = 90

Let it run 1 hour to top off the batteries, now reading:
DC Volts 14
DC Amps 40

The only thing on in the coach is a 110v fan, nothing else.

House batteries are 4 months old, start batteries 2 years - all topped off.

I was able to read voltage at the transfer switch before the circuit tripped.
Generator off, ac plugged into the garage (no gfi circuit) load and line voltage were both 107 volts.

Any idea what is using so much power and why I am now at 107 volts? Thanks.....

John

[Bill Sprague]

Based on my sense of your topic, the batteries have been used for power for awhile.  Now the system is charging them back up and it takes longer than you might expect.  3 or 4 hours is not a surprise for battery charging.

[John Padmore]

Bill, I believe you are right.
After running the generator for another 2 hours the amps went to 10 - amazing.
I'm beginning to actually like this electricity stuff - LOL      Thanks.....

John

[Edward Buker]

John,

Does your coach have a panel that measures AC amps? If so see what is being pulled on each leg or combined. Now that you have charged enough to get down to 10 amps DC you should be much better off AC wise. Regarding the extension cord, how long is it? What wire gauge is it? If you can get a cord that is 12gauge wire that is not much longer than it needs to be you will be better off. I would say a 14 gauge cord is minimum. You must have been about 120V at the outlet and that cord dropped 13 volts along the way to the coach with the amps you were pulling. You are probably better now but the better/heavier the cord gauge wise the more usable power you can deliver to the coach up to the 20amp supply limit.

In this situation with just a 20 amp supply you are best off just leaving things plugged in rather than have the batteries get depleted and then try and bring them back up again.

Later Ed

[Joel Ashley]

I'm not fond of that 107 volt number.  On my coach that is about the bottom allowable source power.  After that, if not before, you risk harming any devices on board that demand high startup power, like air conditioning motors.  In an RV park, that is often caused by too many indians around the fire, but at home... ?  Your cord or its plugs may not be up to passing adequate voltage through;  that's known as voltage drop, and occurs over longer lengths of inadequately sized cord or other wiring components.  And don't be too quick to ignore that fan;  they can pull some juice too.

Joel