50 amp display discrepancy

wfrazier · 06-26-2013, 08:27 AM

When plugged into a 50 amp service my Powerline Energy Management System only indicates that I am plugged into 30 amps. Also, the loadmeter display indicates a lower number the greater the load that is demanded. i.e. When A/C is on the load is showing 17 amps and when the Microwave is turned on (added) the loadmeter drops to 2 amps??? Any ideas out there?

BFlinn181 · 06-26-2013, 08:36 AM

Since 50 amp RV lines contain 2 legs of 50 amps, it could be that your display is showing the load on one leg (the A/C, 17 amp load) and the other leg with the 2 amp microwave load. I know on my Progressive EMS it shows the loads on each leg as it flashes through it's displays. Not sure about why it only shows 30 amp hookup, unless it detects a bad connection and only interprets it as 30 amp because it's not seeing both legs of a 50 amp supply.

You also might do a search at the top of the page about the Powerline EMS, others have had issues caused by interference from other systems in the coach or shore line and suggest doing a reset by using the house battery disconnect for a minute.

Here's one such thread:
http://www.irv2.com/forums/f101/powe...ms-101418.html

Clifftall · 06-26-2013, 08:37 AM

When my EMS was showing amps on 50 amp ( it should only show amps on 30 amp ) it was because I had shut off the W/D circuit breaker. I removed the W/D so I thought it prudent to turn off that breaker. The EMS thought differently

Tony Lee · 06-26-2013, 11:28 AM

You don't say whether this is a new problem on a long-ago installed system or a newly-installed system.

Not familiar with how the measurement is done but - Assuming it is a newly-installed system and it uses a current transformer to measure total current in both legs, it is likely that one of the legs is passing through the CT in the opposite direction to the other. (I would have thought it would need each leg to be independently monitored but maybe not)

ernieh · 06-26-2013, 12:56 PM

Quote:

Originally Posted by wfrazier

When plugged into a 50 amp service my Powerline Energy Management System only indicates that I am plugged into 30 amps. Also, the loadmeter display indicates a lower number the greater the load that is demanded. i.e. When A/C is on the load is showing 17 amps and when the Microwave is turned on (added) the loadmeter drops to 2 amps??? Any ideas out there?

You don't state what year your coach is, but I can tell you how my 03 Journey worked.

The way that they monitor the load on 30A is by measuring the current flow on the neutral leg. That way they can measure the total current flow with one sensor. If you are seeing a measurement when connected to 50A, you are seeing the difference between the two hot legs.

As I recall, my display was blank when connected to 50A because the reading is basically meaningless for most users.

RustyJC · 06-26-2013, 01:07 PM

A properly wired RV 50 amp 120/240VAC service will show 120 VAC between either L1 or L2 and N, and will show 240 VAC between L1 and L2. Unfortunately, there are 50 amp campground pedestal installations where L1 and L2 are wired in phase instead of 180 degrees out of phase, as they should be. If L1 and L2 are in phase, the voltage between L1 and L2 will be 0 VAC. If your EMS isn't seeing 240 VAC between L1 and L2, it may be thinking that it's connected to a 30 amp receptacle. I'd check the voltage reading between L1 and L2 at the pedestal receptacle as a starting point.

NOTE: Miswired 50 amp receptacles are a fire hazard since the neutral currents become additive instead of subtractive. This means that in a worst case scenario you could subject the neutral conductor in your power cord to 50 + 50 = 100 amps when it's only sized for 50 amps (the maximum current it could see with a properly wired 50 amp receptacle).

Rusty

grtharris · 06-26-2013, 07:39 PM

X2 RustyJC, if you have dropped a leg in the coach I don't think the amp reading would go down when you increased the load.
L1 to L2 should be ~240VAC
L1 or L2 to N should be ~120VAC
L1 or L2 to G should be ~120VAC

KIX · 06-26-2013, 07:46 PM

WFrazier.......sounds like your water heater CB is off. If it looks like it's on then cycle it.

wfrazier · 06-26-2013, 08:44 PM

A few months back my electric heating element of my water heater failed and I flipped the circuit breaker off. Since the gas side works fine and the water heater has to be slid out to replace the element I have not been in a hurry to do it. This is probably the first time I have been plugged into 50 amps since then. Most of the places I go only have 30 amp service. I will drive to a location with 50 amp service and check it out and let all know. Thanks for the replies!

NOTE: Its a 2002 Journey DL 36LD and this problem is recent without any modifications or replacements (other than turning off the water heater c/b).

wfrazier · 07-06-2013, 08:38 PM

KIX,

The Water Heater CB solved the issue. Thanks for saving me some troubleshooting. I'm curious if you had a similar problem before or are you just an electrical wizard?

Thanks Again!

grtharris · 07-06-2013, 09:09 PM

Now that is strange, but after looking at the drawings it appears the power for the EMS comes from the water heater breaker.

Clifftall · 07-07-2013, 03:45 AM

Glad it's fixed now. As I mentioned in my post , the same happened when I switched off the WD breaker.

KIX · 07-07-2013, 01:09 PM

Quote:

Originally Posted by wfrazier

KIX,

The Water Heater CB solved the issue. Thanks for saving me some troubleshooting. I'm curious if you had a similar problem before or are you just an electrical wizard?

Thanks Again!

I am not by any stretch of the imagination an electrical wizard.

Luv2go · 07-07-2013, 03:07 PM

Quote:

Originally Posted by grtharris

Now that is strange, but after looking at the drawings it appears the power for the EMS comes from the water heater breaker.

As RustyJC pointed out, the EMS works by detecting 240V across two breakers, one connected to each of the hot legs (L1 and L2) of the 50A plug. The OP's EMS just happens to be using the water heater breaker as a place to detect one of the hot legs. Our coach has the EMS wires on the two A/C breakers, one A/C breaker is connected to each hot leg.

As ernieh pointed out this particular EMS type measures the current on the Neutral wire. The reason why the amp reading went down is when the OP turned on the microwave was he was really turning on a load from the other leg, i.e. his A/C is on L1 and the microwave is on L2. When you have the same load on each leg of a 50A RV feed the current through the Neutral wire read by the EMS will read zero. The OP just happened to see the misleading reading because he had his Water heater breaker off which fooled the EMS into thinking he was on a 30A feed.