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PMSPKS · 06-04-2017, 07:10 AM

Quote:

Originally Posted by imob

Here is an example of how most 50 amp panels work. I have not worked on any of the 240 panels yet, but that is what I was told of the how and why for the newer 240 panels. Your mileage may vary.

OK, I understand how the breaker panel works and each 120v buss is fed, one by L1 and one by L2 through an individual 50a breaker (tied together with a bar). I have verified that the 50a breakers are good (through a continuity check across the breaker). I have verified that I have 120 volts coming to each breaker, at the breaker, for both L1 and L2. Do you think it is possible that there is a break in the buss? That is about the only thing I haven't checked. That doesn't seem plausible.
Another thing, if I have 120v on L1 and L2 at the breaker, how can it be possible that there is something wrong at the ATS?
Thank you to all who have responded. This issue is really baffling to me.

8850hp · 06-04-2017, 08:10 AM

Based on what you've already done, I'll assume that you comfortable working on a live distribution panel, otherwise have an electrician look at the problem.
Yes it is possible that there is a break in the distribution buss, or that the 50Amp breaker where L1 and L2 come in is not making good contact with the buss, or possibly, although very unlikely, the neutral side has become detached from the side which is not working. From reading your comments, earlier you stated that you can measure 120 volts at the input side of L1 and L2, at the breaker, and that you have changed the breaker, with a new one, and the problem symptoms have not changed. Is that information still true?
If that is still true, then I would be more seriously investigating the breaker panel and all of its connections, to make certain that all connections are tight. To do this, disconnect line cord from the pedestal, turn off the breaker from the generator, turn off the inverter, shut down the solar if you have it, turn off the chassis and coach batteries. The objective is to remove all power from the breaker panel before you go in there to tighten any connections. After you've completed checking, don't forget to turn it all back on.
In checking connections, insure all the wires are firmly connected to their respective connection points, and that none of the breakers have pitted or burned connections to the common busses in the breaker panel. The breaker panel will be broken ou into 2 sections (as shown in previous diagrams), exactly how, is a manufacturer choice. The neutral, and ground sections, although separate, should have all neutral wires common with each other, and all grounds common with each other.
Let us know what you discover.

imob · 06-04-2017, 08:26 AM

Quote:

Originally Posted by PMSPKS

OK, I understand how the breaker panel works and each 120v buss is fed, one by L1 and one by L2 through an individual 50a breaker (tied together with a bar). I have verified that the 50a breakers are good (through a continuity check across the breaker). I have verified that I have 120 volts coming to each breaker, at the breaker, for both L1 and L2. Do you think it is possible that there is a break in the buss? That is about the only thing I haven't checked. That doesn't seem plausible.
Another thing, if I have 120v on L1 and L2 at the breaker, how can it be possible that there is something wrong at the ATS?
Thank you to all who have responded. This issue is really baffling to me.

Beak in the buss bar... plausible, no ... possible yes. And at this point it seems that you have ruled out most everything else. The task here is just keep the trace going from end to end and find where the power stops. Pull the breakers off the dead buss and touch the bar with the meter. Go all the way down the bar. It is also possible that there is a mount to the dead bar is broken and when you push in the main breaker that side buss bar is not actually getting pushed into the breaker contact.

Keep going on your trace, you will find the break

twinboat · 06-04-2017, 09:11 AM

Someone mentioned the breaker testing good with a continuity tester but not carrying current under load.

That is still possible if you haven't replaced the double breaker.

Take out the double, swap in a single in the affected position and see what happens. If things on that side work, get a new double.

windsorbill · 06-04-2017, 10:45 AM

Quote:

Originally Posted by PMSPKS

OK you electrical experts, I am at my wits end. I have lost power to 1/2 of the 120 volt electrical buss. The 50 amp main breaker is good, I have checked it. Both L1 and L2 coming to the breaker are hot. Only one half of the circuits are hot, the other half are not. I can usually figure these things out, but not this one. Any ideas?

I have a reset c/b on my inverter. Easy to miss and not see it popped out. When it does pop out, it only effects some of the plugs in the coach.

Old-Biscuit · 06-04-2017, 12:01 PM

WHAT circuits are NOT working..........???

Have you checked that BUS is actually being energized?

Problem must be in Main Panel otherwise Line side of the individual branch circuit breakers would be hot and problem would be downstream

Dutch Star Don · 06-04-2017, 12:41 PM

You may be way past this, but as "windsorbill" noted, half of your electrical power runs through the inverter which has it's own circuit breaker(s). Have you checked the circuit breaker(s) on your inverter. All of your checking for power on both sides of your breakers would indicate to me that you do have power all the way through the system, until you get to the inverter. If it's an inverter circuit breaker, nothing will be powered downstream of it, even when its bypassing power and not on.

allynne · 06-04-2017, 01:12 PM

I think WindsorBill and DS Don have it right. There is a 30 amp cb on the inverter. If it pops, half of your circuits will be lost. The easiest fix is to reset it.

Al Sawyer
'05 Mt. Aire

cruzbill · 06-04-2017, 01:25 PM

I thought the OP said he had 120v on the line side of both 50a breakers? Not true?

Rkesselus · 06-04-2017, 10:14 PM

Quote:

Originally Posted by imob

Actually most coaches are not wired 240. They are 2 independent 110v 50 amp lines. Some new or larger coaches are wired 240. Usually the ones that have larger dryers or an induction stove top are wired 240. Yes checking power at the ATS would be appropriate but based on the description I was assuming that was done. The converter would have nothing to do with this situation as that is tied into the breaker panel and would be in line after the main.

That is correct but if you read across them you should get 240 if it is wired by code.

PMSPKS · 06-05-2017, 07:23 AM

Thank you all for your comments and suggestions. I haven't been able to get back to the MH, but you have given me several things to investigate. I will report back with what I find.

hohenwald48 · 06-05-2017, 07:52 AM

I have seen improperly wired shore power pedestals that actually have the two hot legs jumpered together. Measuring either hot leg to neutral will provide a 120V reading which might appear to be correct. However, reading hot to hot will render no voltage (instead of the 240V as on a properly wired pedastal). Most energy management systems will do this reading automatically to determine if the RV is connected to 30Amp or 50Amp.

It's possible that "you" think you are plugged into 50Amp and your "EMS" thinks you are plugged into 30Amp. This might cause your EMS to "shed" loads based on current draws. Just something to check.

Someone said 50Amp service is not 240V but they are incorrect. A properly wired 50Amp service will always have 240V available between the 2 hot legs. Just because most RVs don't have 240V appliances doesn't mean 240V is not available in the panel. If you don't believe me just lift the neutral and see how many of your appliances emit vast quantities of smoke.

Just kidding, please don't lift the neutral. Trust me on this.