Originally Posted by Tdccmc
Don't need WD, so cut breaker off attempting to prevent EMS from providing power to that unit.
Don't turn breakers off. Even if the light on the EMS is on, it is not forcing current into that appliance, it's just saying that the appliance will be allowed to run if it wants. If you are not using that appliance and don't have it turned on, turning off the breaker will accomplish nothing.
In fact, turning off the breaker can cause problems. As has been mentioned, the EMS checks the incoming power voltages to determine what kind of connection you have and how much power usage it should allow. It does this by looking at the outputs of a couple of the breakers (which ones depend on the way it was installed.) If you turn off those breakers, you will deprive the EMS of the information it needs to properly manage your loads.
So, leave the breakers on, and turn off any appliances you don't need at the appliance itself, not at the breaker.
So cut refrig breaker off to see if wired incorrectly. Still have light on Norcold panel. Shouldn't the light go off on refrig.
Which light? Most of the refrigerator works off of 12 volts, so it will keep working without AC power. The only thing the AC power drives is an electric heater in the cooling system. RV refrigerators actually cool down by heating the ammonia based coolant fluid: this can be done by a propane flame or an AC powered electric heater. But in either case, all of the controls run off of 12 volts.
Why does EMS show WD status on when breaker off?
Because it's not showing that it is in operation, only that it will allow it to operate.
As long as you are not drawing more than 30 amps, all of the lights will go on.
Once it senses that you are using more than 30 amps, it will start to turn off the lights (and the power going to the associated appliance) one by one, monitoring how much the current goes down when it is turned off. It will keep doing this one after another until the total load is less than 30 amps.
At that point, some of the load lights will be off, some may be on. This is saying that any loads that are off are not being allowed to run, even if they way want to, so that more important loads can have the power they need. The ones that are lit will still be allowed to run. (At least as long as the power stays below 30 amps, those other loads may also get turned off in the future if more power is drawn by something.)
The system continues to monitor the power. When the current draw goes down enough that it can turn loads back on, it will one by one start turning them on again, as long as the power stays under 30 amps.
A real world example:
On my rig, four loads are controlled by the EMS: the water heater is the lowest priority, followed by the rear A/C, the washer/dryer, and the front A/C is the highest priority. I've got the following loads "turned on" but they are not necessarily running at the moment, because they have their own thermostats and don't come on unless needed:
- Water Heater - 10 Amps
- Rear A/C - 15 Amps
- Front A/C - 15 Amps
I also have other loads (not managed by the EMS) that are on, like the refrigerator, TV, etc, that come out to 10 amps.
So, all of the thermostats are satisfied, and the coach is drawing 10 amps.
Now, the water heater decides that the water is getting too cool and it turns on. That's another 10 amps, giving 20 amps total. Everything is fine, all of the EMS lights are on.
Next, the rear air conditioner decides that the bedroom is getting too warm, so it comes on. That adds 15 amps, giving a total of 35 amps, which is too much. The EMS responds by cutting off the water heater, noting that the current goes down by 10 amps when it does that. The total current is now 25 amps, and things are OK. All EMS lights are on, except the water heater is off (because it was drawing too much power.)
Next, the front air conditioner decides that the living room is getting to warm, so it comes on. That adds 15 amps, giving a new total 40 amps, which is too much. The EMS responds by cutting off the rear air conditioner, noting that the current goes down by 15 amps when it does that. To total current is now 25 amps, and things are OK. Now the water heater and rear A/C EMS lights are off, the washer/dryer and front A/C are on.
Now, the microwave is turned on, drawing 12 amps. That brings the total power to 37 amps, which is too much. The EMS now turns off the washer dryer, and notes that there is no change to the power draw. So the EMS next turns off the front air conditioner, and notes that the power goes down by 15 amps. The total draw is now 22 amps, and all of the EMS lights are off.
At this point, the water heater and both air conditioners want to run, but they can't because that would be too much power. The EMS keeps watching the power. The highest priority load that was turned off was the front air conditioner, and the EMS remembers that it was drawing 15 amps when it turned off. So the EMS waits until the power drops to at least 15 amps before it will turn that air conditioner back on. When the microwave turns off, the power drops back down to 10 amps. The EMS watches this for a while, to make sure the load stays off, and after a few seconds it decides that it's safe to turn the front A/C on again. It does so, the air conditioner starts up, and the current goes back to 25 amps. Things are still good.
Now, the next highest priority load that was turned off is the washer/dryer. The EMS remembers that it saved no power when that was turned off, so it then checks the rear A/C. That was drawing 15 amps when it was shut off, so now the EMS is again waiting for the total current to go below 15 amps so that the air conditioner can be turned on. But the current load is 25 amps, so it waits.
The living room cools down enough that the front air conditioner goes off. The power drops to 10 amps, the EMS waits a few seconds for it to be stable, then decides it can turn the the rear air conditioner on. It turn on the washer dryer circuit, sees that the current didn't change, so it then turns on the rear A/C. It sees the current go back up to 25 amps.
At this point, only the water heater is cut off by the EMS. It remembers that it was using 10 amps when it was shut off. It knows that with the current 25 amp draw, turning that on would be 35 amps which would be too much, so it waits for the total power draw to be less than 20 amps before it can turn it back on. When the bedroom is cool enough, that air conditioner turns off, the load drops back down to 10 amps, so after a delay the EMS knows it's safe to turn on the water heater. It does so, the total current is 20 amps, which is good.
Now, all of the EMS lights are on, but only the water heater is actually drawing any power. Eventually, the water is hot enough and the heater turns off. All EMS lights are on, but none of those loads are actually drawing power. The total current load is 10 amps, and everyone is happy. The EMS has done its job managing all of those loads and letting as many run at one time as possible.
One more detail to be aware of: the electrical codes say that you should only use 80% of a circuit's capacity on a continuous basis. You should only use 100% of the capacity for an hour or less. Longer than that, and too much heat can build up in the wires. The EMS will enforce that. For the first hour of a heavy load, it will let you use up to 30 amps. After running at 30 amps for an hour, it will lower that threshold by 20% and only let you use 24 amps on a continuous basis. So if you see that the current is 25 amps or more, be aware that the EMS will only let that be for an hour, then it will shed loads to bring it to 24 amps or less.
I had this happen when I was plugged into 20 amps once and was using the air conditioner. The load was right at 19 or 20 amps, and things were cooling, but after an hour the air conditioner shut off (because for 20 amps, the 80% limit is only 16 amps.)