Emergency Electrical Help Please !

[McKenziek]

Just leaving for a trip and something electrical is happening. I was plugged into shore power and running the AC to cool down the coach. I was planning on unplugging and converting to generator so i started the generator and the AC died. I turned off AC, then generator and now when I start the engine a loud alarm is coming from under the dash. I also have no lights inside the coach. I checked all resettable breakers and nothing seems to help. When I plug back into shore power my rig is not recognizing it. Same when on Gennie. I think its a problem with the transfer switch but not sure.

Any suggestions on trouble shooting would be helpful

2005 Monaco diplomat

[MrWizard]

the ATS was installed to be an 'easy choice '
it was never intended to be a 'power switch over during use'

BUT many people seem to think that way
when you tell them different, they refuse to believe it

we had one on here last summer did the same thing at the CG

did not want to be with out A/C for a few minutes
fried his generator,
came on here asking what went wrong, because his generator quit working

and i agree the move the plug from generator socket to shore pedestal and back is the simple safe way
manual Transfer

[pnichols]

McKenziek wrote:
As per what others said I had two issues, the 120 issue i'm guessing is what Mr Wizard mentioned and I definitely learned something here. Disconnect shore power prior to starting generator. I think this fixed itself after waiting a bit for the transfer switch to reset.

Hmmm .... this brings up an argument for the good old (practically obsolete now) method of having to plug one's motorhome power cable manually into something - either a shore post or one's built-in generator outlet box - in order to get power.

In the long run, sometimes the automatic stuff can't be counted on. I at first wished our rig had come with an automatic transfer switch, but not so much anymore.

[McKenziek]

Yep. Lesson learned. I'm glad its all working fine now

[wa8yxm]

Been watching this for a few days

Both shore power (house) and Generator go first to an Automatic Transfer Switch

Then to the main breaker panel

Suspects are: power source (Circuit breaker in house and breakers on Generator)
AUTOMATIC TRANSFER SWITCH (See note below)
Breakers in RV
Converter

NOTE: When you "Hot switch" that is change to/from Generator/shore power while big ticket items ESPECIALLY the Air conditioners are running you run a very serious danger of totallying your Auto Transfer Switch.. Voltages when the thing changes will SPIKE and I mean SPIKE (Can go into the thousands range) and this can weld the solenoid contacts on the ATS.

[McKenziek]

My apologies for not posting. After I got things working we got on the road and were out of cell coverage area all weekend. Thanks to all for chiming in. Here is what I think happened. As per what others said I had two issues, the 120 issue i'm guessing is what Mr Wizard mentioned and I definitely learned something here. Disconnect shore power prior to starting generator. I think this fixed itself after waiting a bit for the transfer switch to reset.

The 12 volt issue was due to a battery kill switch which the previous owner installed and I guess might be faulty. The fact that the lights came back on and then dimmed and then went out made me think of the switch. The switch is a dash mounted type, up is off, down is on. Once I switched off and then back on the dash alarm went out and the lights came right back on.

Thanks again for the replies.

[mchero]

Update??

[time2roll]

If plugged in or running the generator the battery should have about 13.6 volts right on the terminals. If not you need to separate the battery from the charging system to test them each separately.

[MrWizard]

the 12v problem is low batteries OR bad connection

the 120v power problem is the transfer switch OR EMS/surge protection

a hard wired surge protection could have tripped
you switched heavy load between power sources that are NOT synced in phase
thats a big spike in the circuit when switching a running a/c compressor

I 'HARP' about starting generator while plugged in, and/or plugging into shore power while the generator is still running

i always catch flack for saying this, there is always somebody posting they been doing for years, always do this, never had a problem

you have just suffered the result of that action

the 12v is probably another problem, was shore power 15amp or more?
its possible an Energy magament system, shut off the 120v to the converter to keep the a/c going, and your converter 'might be ok' and will recharge the batteries when you straighten out the 120v power problem

[John_Wayne]

For a quick check of your ground take a set of jumper cables put them on the neg. post and the other end of the cables on bare metal of the frame. If things work trace down your ground cables. Had a friend neg. cables looked good on the ends BUT were bad inside the cable covering.

[DownTheAvenue]

I bet your current problem is not related to your A/C or the generator. I bet you have a bad ground. Check all the cables very good, and make sure there is no corrosion. A loose ground could also be the issue. Follow the negative cables until they reach a ground and make sure there is a good connection.

[punomatic]

McKenziek wrote:
I also have no lights inside the coach. I checked all resettable breakers and nothing seems to help.

Any suggestions on trouble shooting would be helpful

2005 Monaco diplomat

Most lights in RVs are 12 volt and would be on a fuse rather than a breaker. If your battery is charged and no fuses are blown, your lights should work, whether or not you are plugged into shore power.

If your battery is low or discharged and your lights don't work, I would say you may have a bad converter. OTOH, if your transfer switch is stuck with both sides of the system disconnected, it could prevent the AC power from being accessible via shore power or genny. That would also prevent your converter from providing 12V power to the lights.

First thing to check is whether there is power at the AC outlet your coach is plugged into (or at the genny output). If there is, but no AC power is available in the coach, check for 120V at the transfer switch. If there is no power there, there is a break in the circuit between the power source and the transfer switch. If there is power at the transfer switch but not at the breaker panel, I would say your transfer switch is faulty.

Good luck with this problem. There's nothing quite as frustrating as technology that doesn't work as expected.

[McKenziek]

After resting for awhile I got lights but they are very dim. Alarm could be for low voltage maybe.

Gennie breaker is good
GFI is good

[turbojimmy]

Sorry I don't have any insight beyond the following:

1) I always shut down all the loads before starting the generator. Let the generator warm up a bit, then load it up (though I have flash cut before unintentionally without issue)

2) When the A/C died, was the generator still running? If so, does the generator itself have resettable breakers on it? Mine does, in addition to the breaker panel inside (but my rig is much older so YMMV)

3) Some 12V things working but not others is odd and seemingly unrelated to your 120V issue. Check your 12V fuses and breakers (if you have any).

4) I'd check for whatever your mechanism is for switching between 120V from the inverter, genny and shore power (transfer switch)

5) I'd start with finding where the alarm from under the dash is coming from. Sounds like a clue.

[McKenziek]

Hmmmm, some 12 volt items work like the fridge, slide outs, inverter is humming, etc. So now im thinking converter but now idea where it is on this coach.