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  • Simple power display panel addon

    Click image for larger version  Name:	meter.jpg Views:	0 Size:	35.1 KB ID:	40895 Since I removed the kitchen satellite/cable wall plate as it will never be used as such I rerouted the power switch for the 2000w inverter from the basement making it more convenient to use the inverter as needed and I also added a digital display for AC volts and amperage. It comes in real handy when you are on a 30 Amp site for rationing your power usage so you don't keep tripping the pedestal breaker.
    Also handy for knowing how much voltage you are getting as well. Instant piece of mind. It's a DROK AC 500V 200A ammeter voltmeter panel from Amazon that comes with a doughnut shaped sensor you slide over the neutral side [white wire] of your power for reading current draw.

  • #2
    Originally posted by Livin Large View Post
    Click image for larger version Name:	meter.jpg Views:	0 Size:	35.1 KB ID:	40895 Since I removed the kitchen satellite/cable wall plate as it will never be used as such I rerouted the power switch for the 2000w inverter from the basement making it more convenient to use the inverter as needed and I also added a digital display for AC volts and amperage. It comes in real handy when you are on a 30 Amp site for rationing your power usage so you don't keep tripping the pedestal breaker.
    Also handy for knowing how much voltage you are getting as well. Instant piece of mind. It's a DROK AC 500V 200A ammeter voltmeter panel from Amazon that comes with a doughnut shaped sensor you slide over the neutral side [white wire] of your power for reading current draw.
    Going to add this to modification list! Thanks for taking the time to post.

    Howard
    Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

    2017 Ford F-350 DRW, '19 315RLTSPlus

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    • #3
      Am I correct in assuming that on a 50 Amp site it would not read correctly? With it reading the neutral, and the two legs being out of phase, the current would subtract, so I guess you would see the net difference of the two phases? (My physics classes were a while ago now lol)
      Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

      Neil Citro
      2018 Reflection 28BH Pepwave
      2019 F350 6.7L Long Bed Crew Cab

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      • #4
        The idea behind this is an easy low cost way for power rationing a 50 AMP unit on a 30 AMP post. It's certainly nothing fancy like those intelligent power panels you see in some high end motor homes. As for the phases cancelling each other out you could be right. My neighbor has 50 AMP, I'll ask him if I can try his pedestal if my cord will reach. I'll update when I know for sure.
        Last edited by Livin Large; 01-26-2021, 06:02 PM.

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        • #5
          Update: I hooked up to a 50 AMP site at another campground and after turning on the hot water, coffee pot, microwave, fireplace and space heater, I got a 44 AMP draw according to my display. It would seem to be working correctly after all.
          Click image for larger version  Name:	amps.jpg Views:	118 Size:	60.6 KB ID:	46078
          Last edited by Livin Large; 03-23-2021, 06:04 PM. Reason: Edited to add that no dog bone was used here. This was a full 50 amp pedestal at this campground.

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          • #6
            Originally posted by Livin Large View Post
            Update: I hooked up to a 50 AMP site at another campground and after turning on the hot water, coffee pot, microwave, fireplace and space heater, I got a 44 AMP draw according to my display. It would seem to be working correctly after all.
            Click image for larger version

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            Thats great, they must be accounting for the phase differences somehow.
            Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

            Neil Citro
            2018 Reflection 28BH Pepwave
            2019 F350 6.7L Long Bed Crew Cab

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            • #7
              The reason it works is because the meter measure the current on the neutral not the hot(s). If you look at a 50 amp to 30 amp adapter, the 2 hot legs are joined on a single phase. This works because a camper runs on 110v returning everything through the neutral. If anything in the unit ran on 220v, it would not pick up that current as all of the current runs through the hot legs only and not the neutral.
              Joseph
              Tow
              Vehicle: 2024 GMC K3500 Denali Ultimate Diesel
              Coach: 303RLS Delivered March 5, 2021
              South of Houston Texas

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              • #8
                Originally posted by Jlawles2 View Post
                The reason it works is because the meter measure the current on the neutral not the hot(s). If you look at a 50 amp to 30 amp adapter, the 2 hot legs are joined on a single phase. This works because a camper runs on 110v returning everything through the neutral. If anything in the unit ran on 220v, it would not pick up that current as all of the current runs through the hot legs only and not the neutral.
                Yeah but when connected to 50 amp service the two hots are out of phase, so the current on the neutral would normally subtract. That’s why your neutral does not need to be big enough to handle 100 amps, but you could be drawing 100 amps from the pedestal (two 50 amp legs).

                They must be somehow accounting for the phase difference to track the neutral current on both phases, which is awesome.
                Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

                Neil Citro
                2018 Reflection 28BH Pepwave
                2019 F350 6.7L Long Bed Crew Cab

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                • #9
                  Originally posted by Jlawles2 View Post
                  The reason it works is because the meter measure the current on the neutral not the hot(s). If you look at a 50 amp to 30 amp adapter, the 2 hot legs are joined on a single phase. This works because a camper runs on 110v returning everything through the neutral. If anything in the unit ran on 220v, it would not pick up that current as all of the current runs through the hot legs only and not the neutral.
                  A 50A to 30A adapter uses only one leg of the 50A because the other leg is out of phase. Caution needs to be exercised when using one of these adapters because you have a 50A breaker “protecting” a downstream 30A circuit.

                  Rob
                  Cate & Rob
                  (with Border Collies Molly & Angel + Kitties Hazel & Elsie)
                  2015 Reflection 303RLS
                  2022 F350 Diesel CC SB SRW Lariat
                  Bayham, Ontario, Canada

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                  • #10
                    Well being that it's AC current, the flow is in both directions at the same time on each leg. My guess would be that the device is not sensitive enough to distinguish between the 2 separate phases. Even though they are out of phase by 180 degrees the electrons still need to flow into and out of the neutral for both legs, the electrons do not flow from one hot leg to the other just because you are drawing on both hot legs. You are correct that the neutral in a true 220V systems can be much smaller. In most (not all) 220v systems, the neutral is the same size as the hots. That way if something goes south, the neutral can pass the necessary current without burning up.

                    Likewise, the I do not thing 50 amp service campers pull 50 amps. There's not that much more stuff in a 50 amp camper vs a 30 amp camper other than the additional AC units. If a camper were to pull a true 30 amps per leg that would be 60 amps into the neutral.
                    Joseph
                    Tow
                    Vehicle: 2024 GMC K3500 Denali Ultimate Diesel
                    Coach: 303RLS Delivered March 5, 2021
                    South of Houston Texas

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                    • #11
                      Originally posted by Cate&Rob View Post

                      A 50A to 30A adapter uses only one leg of the 50A because the other leg is out of phase. Caution needs to be exercised when using one of these adapters because you have a 50A breaker “protecting” a downstream 30A circuit.

                      Rob
                      Sorry Rob, let me rephrase that. The way a 30 amp RV Male to 50 amp Female works is by joining the hot legs of the female together. This means you have a 30amp breaker protecting the 50 amp camper.
                      Joseph
                      Tow
                      Vehicle: 2024 GMC K3500 Denali Ultimate Diesel
                      Coach: 303RLS Delivered March 5, 2021
                      South of Houston Texas

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                      • #12
                        Originally posted by Jlawles2 View Post
                        Well being that it's AC current, the flow is in both directions at the same time on each leg. My guess would be that the device is not sensitive enough to distinguish between the 2 separate phases. Even though they are out of phase by 180 degrees the electrons still need to flow into and out of the neutral for both legs, the electrons do not flow from one hot leg to the other just because you are drawing on both hot legs. You are correct that the neutral in a true 220V systems can be much smaller. In most (not all) 220v systems, the neutral is the same size as the hots. That way if something goes south, the neutral can pass the necessary current without burning up.

                        Likewise, the I do not thing 50 amp service campers pull 50 amps. There's not that much more stuff in a 50 amp camper vs a 30 amp camper other than the additional AC units. If a camper were to pull a true 30 amps per leg that would be 60 amps into the neutral.
                        That’s exactly my point. I’m not saying the neutral can be undersized, I’m saying it does not need to be double the hots.

                        Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

                        Neil Citro
                        2018 Reflection 28BH Pepwave
                        2019 F350 6.7L Long Bed Crew Cab

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                        • #13
                          Originally posted by Livin Large View Post
                          Update: I hooked up to a 50 AMP site at another campground and after turning on the hot water, coffee pot, microwave, fireplace and space heater, I got a 44 AMP draw according to my display. It would seem to be working correctly after all.
                          Click image for larger version

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                          Are all those appliances on the same leg, L1 or L2? If so, then you would read total appliance current.
                          Ted
                          2021 Reflection 310RLS
                          2020 F350 PS,CC,LB,SRW

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                          • #14
                            Well without a schematic of the electrical I don't know which leg is pulling what. One thing is for sure, there is no way I was pulling 44 amps out of a single leg and still maintaining 122 volts and not popping a breaker. At the 30AMP site the meter showed only 113 volts with 21 amps being drawn as in the original post picture. That one is with a Camco dog bone adapter.

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                            • #15
                              Jlawles2 , TedS , OffToHavasu , TucsonJim and all the rest of the other knowledgeable electricians here,

                              If I'm displaying my ignorance...well, so be it. I suspect others have similar questions but hesitate to post. My career has centered on electronics, not electricity...so the 50A circuits in our trailers was new to me when I bought my rig.

                              Perhaps oversimplied, but AC voltage on the hot line pushes or pulls depending on the phase of the alternating sine wave (voltage level). For simplicity, the examples below assume the voltage curve is at their peaks (either positive or negative).

                              Bottom line: I can't "see" how a single measurement device can capture all the current draw on a 50A camper's circuit. What am I missing?

                              BASIC CIRCUIT USED IN THE DIAGRAMS
                              Some labels are removed in subsequent examples to declutter the picture.

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                              Easy Example--only one circuit is powered. This mimics a 30A camper's circuit and would be easy to measure with a single measuring device. The red arrows represent current flow.

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                              Now I'm into territory I don't fully understand so this may be wrong--assuming a perfectly balanced load on L1 and L2, is the neutral "bypassed"?

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                              Even further into the weeds--what if the loads are not balanced?

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                              Howard




                              Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

                              2017 Ford F-350 DRW, '19 315RLTSPlus

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