Electrical load management

Topic: Electrical load management (Read 1089 times) previous topic - next topic

Electrical load management

July 01, 2017, 12:13:49 am

Couldn't find another thread on this so thought I'd ask a question or two about the electrical capacity of my 50amps.

'06 Phenix - when plugged into 50amp today in Sante Fe we tripped the outside breaker. Had two of the three a/c's blowing and wife was washing clothes. When it switched to dryer the breaker flipped.

Does this seem reasonable to you guys? Sure thought 50amps would have gone further...

So I'm new to FT and the rv lifestyle; how should I 'think' about managing the load and the electrical components in the coach?

Appreciate the tutorial....!

Re: Electrical load management

Reply #1 – July 01, 2017, 12:42:07 am

Dryer~12 amps, washer~4 amps, air conditioners~15 amps each. Even if they were all on the same leg that would only add up to about 46 amps. I am curious what else was on? Battery charger? Tv? Lights? Microwave?

Last weekend I tripped one leg of generator 45 amp breaker when I had both air conditioners running as well as an electric griddle and the Advantium oven.

Re: Electrical load management

Reply #2 – July 01, 2017, 12:50:50 am

When washer switched to drier, another 12-14 amps or so. Aqua Hot or similar, when electric element is on another 12 or so amps.

True 50 amp pedestal = 50 amps on leg one, and 50 amps on leg 2 (theoretical 100 amp total if perfectly balanced loads on the 2 legs). Breakers do get weak over time and can need replacement.

Re: Electrical load management

Reply #3 – July 01, 2017, 02:35:03 am

Quote from: sedelange – July 01, 2017, 12:42:07 am

and the Advantium oven.

Steve,

Speaking of your Advantium oven, does it take a very hard (and loud) pull to open the door? Mine sure does.

Thanks,

Trent

Re: Electrical load management

Reply #4 – July 01, 2017, 07:06:40 am

Gilgal,

Here is another possibility that you could have. Did you check the pedestal plug prior to plugging in to see if you have 2 legs of ~120VAC? If you don't have a pedestal checker you need one and use it at every pedestal prior to plugging in. These can be either home made or store bought. You should have ~230 V if you read between both hot legs. (this ties to what AC7880 is talking about) If the park pedestal has what some refer to as false 50 amp this could be your problem. What some place have done is split 1-50 amp leg and use it to feed both your hot legs. If they have done this then the 46 amp draw along with the other normal loads (fridge., converter/inverter) sedelange is talking about could be enough to trip a false 50 amp breaker.

Pamela & Mike

Re: Electrical load management

Reply #5 – July 01, 2017, 08:57:30 am

If they have split the same leg over two then you have only one 50 amp feed rather than two. I'd check the "feel" of the plug going into the pedestal. Too often the receptacle is worn to where there is a lot of resistance at that point. Maintenance people at campgrounds will only change out a receptacle when enough people complain. I've been on both sides of that problem and realize that sometimes the management doesn't want to spend the dollars to correct something that is a problem to their guests. It's kind of like computer programing and trouble shooting the program: it's only a bug if someone discovers it and it's only a problem to the park if enough people complain.

Re: Electrical load management

Reply #6 – July 01, 2017, 09:21:39 am

Thanks for the info. There were a 'few' lights on, and I've converted most of them to LED. The Aqua Hot probably was on because she'd just washed a load.

Mike, I do have a SurgeGuard Model 34850 and it shows both legs with 124v. Receptacle seems right enough to fit. I'm not really too worried about this but I am in the mode of learning all I can - and electricity is my weakest area.

If you have more info or ideas please feel free...otherwise I'll just take these nuggets and pay attention to what goes on over time.

Re: Electrical load management

Reply #7 – July 01, 2017, 09:27:40 am

Quote from: Gilgal – July 01, 2017, 09:21:39 am

Mike, I do have a SurgeGuard Model 34850 and it shows both legs with 124v.

That still might not be telling you if you have true 50 amp service at the post (50 amps on each of 2 legs, or 100 amps total) or if, as several members are suggesting, the campsite is wired with only 50 amp of one leg which is split at the power post). You need to verify with a multimeter. And, as Dan pointed out, the campsite breaker could also be old and in need of replacement.

Here's a good resource RV Electric Click on "outlet testing" for more info on the "false" 50 amp wiring.

Re: Electrical load management

Reply #8 – July 01, 2017, 10:56:23 am

Wow, that's a really eye opening resource on testing the 50 amp service. The electrical engineer that wrote in there says that we should be testing under load before plugging in.

Can anyone tell me how you do that? What device or system do you use? We have the best surge guard which performs several tests for about two minutes prior to 'ok', but it sounds like that's really not a replacement for my own testing with a multimeter and also checking under load.

In the real world do you guys really do this ?

Re: Electrical load management

Reply #9 – July 01, 2017, 11:04:36 am

By the way, the model 34850 claims to check for open neutrals, reverse polarity and other 'stuff' prior to releasing power to the RV.

Surge Guard Electrical Protection System 34850 Installation - YouTube

Taking prior comments into mind I think it is still wise to make sure the campground isn't providing phony 50amp service by using multimeter across X and Y to see 240v.

...still a newbie...thanks for the input

Re: Electrical load management

Reply #10 – July 01, 2017, 12:00:27 pm

Quote from: Gilgal – July 01, 2017, 10:56:23 am

The electrical engineer that wrote in there says that we should be testing under load before plugging in.
Can anyone tell me how you do that?
In the real world do you guys really do this ?
What device or system do you use?

Gilgal,
Not without a lot of extra stuff that most people don't want to carry around.
We don't do a load test only a pedestal checker.
This is a little quicker than a multimeter and can be built by most any novice. There are several ways to personalize one but this will give you the basic info as to how to build a pedestal checker. 50-amp Tester

If you aren't a DIY kind of person then they do make a store bought one of these.

Pamela & Mike

Re: Electrical load management

Reply #11 – July 01, 2017, 12:23:10 pm

Quote from: Pamela & Mike – July 01, 2017, 12:00:27 pm

Gilgal,
Not without a lot of extra stuff that most people don't want to carry around.
We don't do a load test only a pedestal checker.

Same here

Quote from: Pamela & Mike – July 01, 2017, 12:00:27 pm

This is a little quicker than a multimeter and can be built by most any novice. There are several ways to personalize one but this will give you the basic info as to how to build a pedestal checker. 50-amp Tester

and if you do want to build your own and carry around something larger than can test under load, Google found me this interesting little project http://hhrvresource.com/sites/default/files/dfiles/50_Amp_RV_Power_Pedestal_Tester.pdf

Re: Electrical load management

Reply #12 – July 01, 2017, 12:29:12 pm

Does the Progressive Industries EMS-LCHW50 provide this level of checking?

Re: Electrical load management

Reply #13 – July 01, 2017, 12:33:24 pm

Quote from: floridarandy – July 01, 2017, 12:29:12 pm

Does the Progressive Industries EMS-LCHW50 provide this level of checking?

Not load, but EMS-LCHW50 | Progressive Industries, Inc.

Product Features:
• Over/Under voltage Protection
• Open Ground, Open Neutral & Reverse Polarity Detection
• Open Ground, Open Neutral & Reverse Polarity Protection
• Accidental 240V Protection
• Miswired Pedestal Indication
• Surge Failure Indicator
• Amperage Meter Display
• Previous Error Code
• A/C Frequency Protection

Surge Protection: 5-Mode / 3,580J / 88,000A

Re: Electrical load management

Reply #14 – July 01, 2017, 01:27:18 pm

I can see how testing under a small load, such as a 100 Watt light bulb or better yet a small space heater, might uncover some irregularities not found under no load.

Re: Electrical load management

Reply #15 – July 01, 2017, 09:01:46 pm

Does the dryer have a 120 volt or 240 volt heating element ?

wantabe

Re: Electrical load management

Reply #16 – July 01, 2017, 11:23:55 pm

Quote from: wantabe – July 01, 2017, 09:01:46 pm

Does the dryer have a 120 volt or 240 volt heating element ?

wantabe

Every coach I have ever looked at or researched has a 120 volt drier and 120 volt in the combo washer/dryer units.

Re: Electrical load management

Reply #17 – July 02, 2017, 09:51:03 am

Mike, I can be a bit dense sometimes so would love to see a schematic of your tester

Re: Electrical load management

Reply #18 – July 02, 2017, 10:11:28 am

Quote from: Gilgal – July 01, 2017, 12:13:49 am

So I'm new to FT and the rv lifestyle; how should I 'think' about managing the load and the electrical components in the coach?

As others have mentioned above, with 50 amp service there are actually two power source lines, commonly referred to as L1 and L2 (short for Line 1 and Line 2 and sometimes referred to as Leg 1 and Leg 2). When Foretravel wires up our coaches they have to decide what devices go on L1 and L2. They do their best to guess a typical usage so both lines are equally loaded so you don't exceed 50 amps on one and trip the breaker. For example, a 2 AC coach will always have one on L1 and the other on L2. With 3 ACs obviously they have to make a harder choice about which L will get the 3rd AC.

In the scenario above where the breaker is tripping with 2 AC and other misc power loads, I would suspect both of those ACs are on the same line of power. The easy fix is to turn off one of those ACs and turn on the 3rd one. With ducted air it probably makes little difference to comfort.

A more advanced approach is to have amp meters on each line, know exactly what devices are wired to each leg and their approximate real amp draw when on. Your Foretravel manual will have a diagram of the breaker panel (that is under the bed or maybe in a closet) which will tell you which device is on which line but will not likely have real current draw information. It will show the breaker size (20 amps) but not the actual amps when on. For example, my ACs pull about 15 amps each, the microwave about 14 amps, my ice maker 2.5 amps, my engine block heater 18 amps. These will all vary a bit by manufacture/model for your coach.

I put labels on each each device and a corresponding label on the breaker panel. Example: "L1-C2" means line one, breaker (or circuit) 2. A small inconspicuous L1-C2 label on the face of the microwave and one next to the breaker for it on the panel. For the ACs I put the label on the thermostat. Same kind of label on outlets, engine block heater switch, etc. That way I can see which item is on each line without looking it up.

Real current draw information will be very handy whenever you find yourself on 30 amp service where a single 30 amp power breaker (at the RV site pedestal) will be feeding both L1 and L2 and you will be make hard choices about what to turn on or leave off. You end up doing "power management" like turning off the AC when using the microwave.

Re: Electrical load management

Reply #19 – July 02, 2017, 10:32:59 am

Quote from: JohnFitz – July 02, 2017, 10:11:28 am

2 AC coach will always have one on L1 and the other on L2. With 3 ACs obviously they have to make a harder choice about which L will get the 3rd AC.

In the scenario above where the breaker is tripping with 2 AC and other misc power loads, I would suspect both of those ACs are on the same line of power. The easy fix is to turn off one of those ACs and turn on the 3rd one. With ducted air it probably makes little difference to comfort.

Great point!

Quote from: JohnFitz – July 02, 2017, 10:11:28 am

A more advanced approach is to have amp meters on each line, know exactly what devices are wired to each leg and their approximate real amp draw when on. Your Foretravel manual will have a diagram of the breaker panel (that is under the bed or maybe in a closet) which will tell you which device is on which line but will not likely have real current draw information. It will show the breaker size (20 amps) but not the actual amps when on.

At some point they did try to include this info. The below is for a 2003, and to support your idea, you can see in a 42 footer, 2 A/Cs and the AquaHot on electric are on the same leg.

Re: Electrical load management

Reply #20 – July 02, 2017, 12:36:05 pm

What do the IH45s do with four air conditioners and 50a service. The generator is 20 kw which is over 80 amps.

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