Power Management doesn't recognize 30A

[The Newsoms]

We recently camped in our Cardinal 3025FL where there was only 30A service for the first time. We were throwing the breaker at the pedestal. I went to look at the power management board and realized it was showing a 50A connection. I pushed the select button and it would show 50A and Gen (which we don't have), but never 30A. I'm not that great at electricity but have some general knowledge. Wondering if this is something I could correct without driving 2 hours to the dealer and 2 hours back. ~Teresa

[clr]

Nothing to correct I would say. Your 30A to 50A converter is the culprit here. 50A service is two 120V circuits the dog bone 30 to 50 converter combines the two circuits together so that the entire coach can be serviced by the single 30A outlet.

[The Newsoms]

That did cross my mind but since the only way to put a 50A plug into a 30A receptical is to use an adapter, what would be the purpose of the power management system if it always thinks it's plugged into 50A?

[doc73]

Did you turn off breakers to allow for the 30 amps? Nothing wrong with thinking it's on 50amps but if you are still trying to run 50 amps of stuff that could be a problem.

[ependydad]

Originally Posted by doc73

Did you turn off breakers to allow for the 30 amps? Nothing wrong with thinking it's on 50amps but if you are still trying to run 50 amps of stuff that could be a problem.

The Power Management system is supposed to shed loads automatically so that you don't pop the pedestal breaker.

For The Newsoms... maybe contract the maker of the panel/power management system? They should be able to help diagnose/troubleshoot this.

[TheWolfPaq82]

I believe that is a default setting in the PMS. If your trailer is designed for 50A service, then that is what the PMS is set to. Why the pole breaker is tripping...not sure what's with that. Try sending email to Mfg. about the problem. I needed a schematic for the system this year and the mfg sent me one via email. I also found complete trouble shooting directions on line for the unit.

[doc73]

Yes it might supposed to be doing that but with only a 1/3 of the power available it might not handle well?

[clr]

This is what the Precision Circuits Inc. folks have to say about the automatic operation:
Automatic Operation:

30-amp Service - PCS senses 0VAC between L1 and L2. The I/O Module has a current sensor which monitors the current on the neutral wire. When the current exceeds the 30-amp limit, because possibly the owner has turned on the Microwave, the Mini-PCS will limit the current by shedding appliances. Once the total RV current has dropped, for example because an owner operated appliance has been turned off, the Mini-PCS will reverse the above procedure, returning power to appliances whose operation was not immediately critical. Appliance shed order is easily determined by the manufacturer by
wiring the appliances to the appropriate number relay.
20-amp Service - Mini-PCS senses 0VAC between L1 and L2, and the owner selects 20A on the Remote Display. Mini-PCS performs the same functions as above except that it limits total current to 20amps.

Generator - Mini-PCS senses power to the Genenerator Hour Meter. In this mode Mini-PCS assumes enough power is available and goes to sleep. It displays the fact that Gen-Set is running, that all Loads are powered.

50-amp Service - Mini-PCS senses 240VAC between L1 and L2 to determine this mode of operation. In this mode Mini-PCS assumes enough power is available and goes to sleep. It displays the fact that 50-amp Service is available and that all Loads are powered.

As I read the above for auto operation and connected via the dog bone to 30a service you would have 120vac to both L1 and L2 but they would be the same phase. To operate the auto PMS system it would have to see 0 VAC, if the load on L1 and L2 is not similar you may see a couple of volts between L1 and L2 that may be sufficient to keep you from sensing 30Amp service.

I would recommend you talk to the support folks a Precision Circuits and see what they say.

[WolfWhistle]

If you plugged into the standard 30 amp outlet (3 pin) at the post and used a good 30 to 50 amp adapter the PC, Inc unit is automatic; like what was already shared... there would be 0 volts between L1 and L2 and it goes into the 30A mode and sheds loads as needed. It sheds loads in a particular order, determined by what breaker each load is wired to. If your adapter wasn't delivering 120v on both L1 and L2 that could be an issue. If the breaker on the post was 30A but wired to a 50A 4-pin plug, the PCI unit would not know to shed loads.
WW