Quote:
Originally Posted by JRTJH
Our EMS has an "current amperage" readout that displays on the LED status window. So, for us (and most people who have a Progressive EMS) all you have to do to determine "current amp load" is isolate that breaker by turning all the others OFF and look at the amp load on the EMS display.
This is much easier than trying to use a multimeter or ammeter to do the same thing.
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Surge Guard also has a unit (34951) that can be used with a remote monitor (40301) that displays current, watts, voltage, and frequency.
Whichever monitor and method you use, remember that current flow is in part a function of supply voltage available. If the supply voltage drops under heavy load, the current flow will increase for most loads. So, if you have a shore power supply with under-sized wiring, it is quite possible to see the voltage drop significantly during heavy use. (We had an old 30A supply at the house that would drop voltage 10-15% when under heavy load.)
The "one-at-a-time" ON method provides general guidance. At the end of the test turn on as much equipment as your supply will support and make sure that the voltage doesn't drop significantly (e.g. 120 to 105). If it does, then consider a "one-at-a-time" OFF test to see the impact of current on a heavily loaded system.
Your EMS will kick off at some low voltage - the Surge Guard referenced above will open (shut off power) at 102 Volts. A load of 30A @ 120V = 3600 Watts. That same load in watts @ 103 volts will pull 35 Amps and trip your breakers. This is a case where you might find breakers popping in your trailer or at the pedestal with no apparent problem listed on your EMS. So, in running your tests, pay attention to the voltage as well as the current. [One of the reasons I really like the Surge Guard - provides KiloWatt readings on the remote monitor.]
You might find this issue in older parks or parks where the service was under-designed or poorly maintained [or in my back yard if connected to the old swimming pool wiring]. And the presence of a lot of "neighbors" on the same service in an RV park will only make matters worse.
Just something else to consider...