Community Forums

rkdillinger · 06-30-2022, 07:04 PM

I've been doing a lot of research on this problem and have not been able to find a solution for my exact situation, so here's what's going on:
I've been at this campground for over a month, plugged into the 50A outlet on the power pedestal, and everything has been fine. We left the rig for a week, and when we came back the EMS display was now only showing 30A. I have verified/tested that I have 120V on the black and red lines at the junction box where the power cable comes into the rig, and 240V across the two, so the cable and plug are good. After the junction box the wires go up into the rig. I pulled the cover off the circuit breaker box and, according to the manual for my "50 AMP Smart Energy Management System Model 900", I checked the voltage from J6-1 to Neutral and measured 120V. I checked the voltage from J6-3 to Neutral and also measured 120V. But when I checked the voltage from J6-1 to J6-3 it measured 0 instead of 240V, which is why the EMS believes I am on a 30A service. Somewhere between where the power enters the rig and gets to the breaker box I am losing a 120V leg. I have seen several posts that mention a "Transfer Switch", but I have no idea where that's located, or if it might be the cause of the issue. Any ideas? I have a 2005 Fleetwood Excursion 39S.

Thanks,

Randy

jacwjames · 06-30-2022, 07:08 PM

The EMS display/module requires power to operate, on mine the power comes from the washer/dryer breaker that is not controlled by the EMS. If that breaker is off the EMS will only display 30 amp.

Make sure all your breakers are on.

Skip426 · 06-30-2022, 07:16 PM

A similar post in the past three weeks , one member mentioned that ALL the circuit breakers need to be reset , to be sure the EMS is getting the second leg feed it needs to recognize the 50 amp supply .
I believe the dryer circuit was one feed , no mention of the other .

Does your coach have a cord reel ?
Have you tried moving it ?

EDIT : I see Jim types faster than I do ... boy I type slow .

rkdillinger · 06-30-2022, 07:18 PM

Quote:

Originally Posted by jacwjames

The EMS display/module requires power to operate, on mine the power comes from the washer/dryer breaker that is not controlled by the EMS. If that breaker is off the EMS will only display 30 amp.

Make sure all your breakers are on.

All breakers are on (As verified by having 120V at the EMS J6-1 terminal).

Thanks,

Randy

rkdillinger · 06-30-2022, 07:23 PM

Quote:

Originally Posted by Skip426

A similar post in the past three weeks , one member mentioned that ALL the circuit breakers need to be reset , to be sure the EMS is getting the second leg feed it needs to recognize the 50 amp supply .
I believe the dryer circuit was one feed , no mention of the other .

Does your coach have a cord reel ?
Have you tried moving it ?

EDIT : I see Jim types faster than I do ... boy I type slow .

There is no "Cord Reel". I measured the incoming voltage right at the junction box for the inbound power cord and the inside of the RV, so the power is good right before it goes into the internals of the RV.

The J6-1 Terminal measures 120V to neutral which is from one leg of the 50A breaker (washer/dryer), and the J6-3 measures 120V to neutral, which is from the other leg of the 50A breaker (Inverter Main), which confirms that both breakers are passing 120V to the EMS J6 connector. But they do not measure 240V across J6-1 and J6-3, so somewhere between my junction box coming in from the pedestal, and the breaker box, I'm losing a leg. I just can't figure out where.....

Thanks,

Randy

Skip426 · 06-30-2022, 07:23 PM

Quote:

Originally Posted by rkdillinger

All breakers are on (As verified by having 120V at the EMS J6-1 terminal).

Thanks,

Randy

Ok with a test of circuitry inside the coach I think you've eliminated the ATS as the problem

If you start the gen set , does that return all to operational ?

rkdillinger · 06-30-2022, 07:32 PM

Quote:

Originally Posted by Skip426

Ok with a test of circuitry inside the coach I think you've eliminated the ATS as the problem

If you start the gen set , does that return all to operational ?

Yes, if I start the generator everything functions normally. It has to be somewhere in the line between the junction box and the breaker box. The breaker box is under the bed pedestal, and the junction box I believe is under the bed pedestal, so I'm guessing there's something going on under the bed. I'm going to have to take that all off and see if I can get access to that area.

Thanks again!

Randy

Archer2 · 06-30-2022, 08:43 PM

I’m confused by what the “Junction Box” is. Since you have a generator that apparently will come online and power everything you must have an Automatic Transfer Switch. Is it possible that what you are calling the junction box is really the ATS? Somewhere in your coach wiring the shore power cord AND the generator output both have to be connected to the ATS and the output of the ATS will be connected to the 2 50A L1 and L2 main breakers in the EMS integrated load center.
The only way I can think of to give you the symptoms you describe unless you have made a mistake in measuring and the shore power circuit really has one leg missing Is for the shore power to somehow have gotten both L1 & L2 connected to the same 120VAC phase. The generator works as expected. And since the generator and the shore power are (basically) the same thing to the EMS circuits, you can probably rule out the EMS. I would look again more closely at the shore power components because I cannot explain how you could have 120V to ground on L1 and L2 while measuring 0V between them unless somebody rewired something in the shore power circuit. Now if you are mistaken and you only have 120V on one leg then that would point to a problem at the pole, the cord, the plug or the ATS.

**NLOVNIT** · 06-30-2022, 09:11 PM

I'll throw this out there, not that it'll help (because I don't understand anything about voltage & incoming lines), but something similar happened on my 06 Bounder. At about the 12 year mark, all of a sudden the Intellitec displayed 30A on the panel when plugged into 50A. Turned out the EMS circuit board failed. The unit was then determining I had only 30A available & would shed loads when going over 30A even though I was plugged into 50A circuit. Replaced it & all was back to normal.

May not even have anything to do with the OP's issue, especially if he's only getting 30a incoming & it's not just the display showing it/thinking it. But I thought I'd pass this along JIC.

Archer2 · 06-30-2022, 09:31 PM

That’s actually a good suggestion Lori but the fact that everything returns to normal when on generator argues against there being a problem in the EMS. Everything from the output of the Transfer switch on is common to both shore and generator power.

**NLOVNIT** · 06-30-2022, 09:33 PM

Eh, I gave it a shot. I missed the part about all being OK on genny. Thanks for pointing that out.

windsorbill · 07-01-2022, 06:30 AM

Some have said the ATS is fine, but I would open it up (with shore power disconnected, of course), and check all connections. I would pay particular attention to the lugs that connect the shore power to it.

You might post make/model of the ATS also.

Soppy · 07-01-2022, 06:37 AM

Is your generator 240 volt ? . You could have a broken wire somewhere in the circuit. That will explain the 120v on each leg and no 240 v. If your control board doesn't see 240 v , it will configure the system for 30 amp.

Turbojack · 07-01-2022, 07:00 AM

If you have a twist lock connection at your coach, make sure it is twisted tight.

Need to start at pedestal. Check voltage there.
L1-N = 120V
L2-N = 120V
L1-L2 = 240V
N-G = 0
Check continuity between N-G

After that check at the end of your power cord where it connects with the coach wiring.

Keep going further in and see where the above does not work.