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If you are correct about the plugs...........a 30 amp plug has 3 prongs and a 50 amp plug has 4 prongs, then one of two things is most likely happening. Either your cord or panel has a problem on the 2nd leg OR the pedestal has an issue and isn't delivering the proper voltage AT the service location. Sounds like you have a good meter so you should be able to check that pretty easily. And just so you know, you really shouldn't try running two A/Cs on 30 amps. That is only 3600 watts total power available. EACH A/C can draw over 20 amps on a hot day. They are rated at 95 degrees, but the ambient temps on the roof can reach 130 or more which increases the amp draw by another 7 amps or so on each one. The amps. So check the voltage on each leg of your service, both at the source and at your load center. And check the amp draw if you can. Somewhere that second leg is pulling more power than it can safely deliver. Another possibility, is that you have the water heater on or some other large draw on that leg. Turn all other AC loads off and check it. The fridge can be about 500 watts on AC mode and the water heater another 1400 watts. That would cause that leg (if both on the same one) to be overloaded. Hope that proves helpful here. Please get back to me if you need more as all follow ups are included in our fee. R.J.
I saw that.........but, if it isn't working and it might not be.........then damage can result. Check the source and then the voltage at your service panel and we can go from there. Testing is the only way to track this down.
Please keep in mind that taking voltage readings alone won't always show the true condition of a circuit. Breakers and relays can open up either partially, or totally under load. Let me know what you find here.
I put this back on the board for other techs to look at.........and I will check my manuals to see what I might have. R.J.
I have been giving this some thought.............and I am wondering if you have a cord reel in use? Sometimes, they will work fine except wen under a larger load (like a 2nd A/C) and even though they read proper AC voltage with a meter, they "open up" on one leg under load. I have seen this once before on a Monaco with a reel. Either that, or someone mislabeled the sides on the system and what says "30 amps" is really 50 and vice versa. I don't know any other explanation. R.J.
Please let me know what it turns out to be as several of here on site are wondering about it. Thanks!