Monitor Your RV’s Shore Power Consumption

Ever wonder just how much electricity your RV is consuming when hooked up to shore power? Want to know just how much each of your appliances is drawing without having to move a meter all over your RV to test everything? Sure lots of RV’s show you how many amps they are drawing at any given time but how much does that calculate to in dollars per hour, day or per month? We wondered the same thing but we couldn’t find a reliable or easy way to meter our usage which would allow us to adjust our usage habits to meet our budget. Ah you know what they say, first search the web to see if anyone built it, if not built it yourself and post what you learned on the internet! This complete total solution will run you under $200.00. That may sound like a lot but you can easily recoup that in energy savings with the data this nifty setup will give you, especially in campgrounds that meter their electricity.

Before we get started:

OK folks, we are working with between 20 and 50 amps of power and if you do not have a good working knowledge of residential electrical systems save yourself the trouble and buy the parts, drop them off at your local electrician and pay him for an hour of his time to put this all together. You might spend 80 bucks in labor but you’ll know it’s done right! Since we live in the good ol U.S. of A we have to say that we aren’t responsible for anything that happens as a result of reading this post or attempting anything you read here. Even making a simple extension cord can cause damage if done wrong so let a pro do it if your unsure or don’t want to assume the risk! Any qualified electrician could build this for you in less than an hour. Ug glad thats out of the way, now onto the cool stuff!

How does it work?

efergyAt the heart of the system is an off the shelf product called an Efergy Elite. This nifty little gadget (we are not paid to say that and we didn’t get it for free, no sponsors here!) is an energy management system designed for residential homes. The problem is that RV’s have different electrical systems that homes since they use a variety of power sources like generators, house batteries and street power so hooking up the Energy in a traditional fashion isn’t generally as easy as the instructions state.

That’s where this nifty gadget comes in. We don’t sell them, this is a do-it-yourself project but the parts are available on our Amazon store. To start, I thought about adding the Efergy system to the main breaker panel (then it would read even when on battery or generator power) but realized that many RV’er (myself included) either didn’t want to start taking apart their RV and possibly voiding their warranty or they used multiple rigs and wanted something completely portable.

IMG_8677OK so it’s basically a modified extension cable, nothing special there. The orange box you see pictured here houses the Efergy remote power sensors that capture power consumption. At the ends you have a standard 50 amp male & female plug by Camco.  What i like about this design is that the wiring insulation stays in tact and out of harms way. For our project we used 6/3 indoor/outdoor wire which is the same wire used in most coaches up to 45 feet on their main 50amp/30amp power feed. It may be a little overkill for 30amp but overkill is always a good thing when dealing with electricity & electrical resistance. Here is a great article on the basics of RV electrics including a chart for what type of wire is recommended at various lengths. Our Amazon links below sell the wire by the foot.

Lets Get Started!

For the purposes of this article we are building a 8 foot extension cord to house the Efergy sensors. You can make your entergy sensor box/cable much shorter but we found an extra 8 feet can come in awfully handy once in a while when parks put their power posts in funny spots. You know when you need those extra couple feet? This can be the solution in a pinch, even if you don’t need to read the sensors.

Before we get started lets look at the materials and tools you’ll be needing.

Materials List:

Tools List:

  • Screwdriver
  • Drill with stepper bit (or 7/8 drill bit)
  • Basic retractable razor blade
  • Electrical Pliers (most any type that can strip and bend wire will do)
  • Multimeter (needed if you want to test before plugging into your rig)

Building Your Cable: 

  1. Drill two holes in your outer housing at opposite sides. Make the holes approx. 7/8 in diameter so your rubber grommets can fit in the holes securely. (see picture below)
  2. Install your rubber grommets in the holes you just drilled, these will keep things dry in bad weather. We used metal electrical grommets for our original box shown in the pictures, but we recommend rubber ones for a better seal and more flexibility.
  3. Cut your 6/3 electrical wire to the desired length of the overall cable. We found you can go at short as 2 feet or as long as you like (under 50 feet to ensure the wire doesn’t build up too much resistance for the gauge)
  4. At one end, measure 18″ from the end and carefully cut only the outer black insulation around the cable circumference. The wire we recommend has a thin but ridged outer insulation that cuts easily with a razor blade and pulls away without issue. Pull the outer insulation off exposing the inner 4 wires (don’t throw the outer insulation out, you’ll be reusing it in step 8!).
  5. Now you should have approximately 18 inches of wire where the Red, Black, White & Ground wires are exposed. There may also be some brown paper which you can cut away as it will just get in the way.
  6. Feed all 4 wires through your rubber grommets into and then back out of the sensor box as showing in the diagram below. Feed the exposed wires from the bottom of the box through to the top of the box so that the outer black insulation goes through the grommets but the inner Red/Black/White/Ground wires are exposed inside the box.
  7. Attach your Efergy sensors around the black and red wires (hot wires). You do not cut the insulation, the sensors read power usage through the insulation. We recommend you do this step early as the sensors are very hard to install once you finish your cable as the gauge of cable is very tough to bend, especially in that small box! You can leave the sensor’s white wires hanging for now as shown in the diagram below.
  8. Now its time to cover up those exposed wires that are coming out of the top of your sensor box. Grab that outer insulation you pulled away during step 4 and cut it to length so that it covers the wires coming out of the top of your sensor box. Slip it over the exposed wire and back down towards the sensor box. When done you should be leaving only 4″ of wire exposed and the black outer insulation should be covering the wires up to your rubber grommets at both ends. efergy
  9. Now its time to install your 50amp (or 30) male and female ends. Your male end will be installed at the top (shorter) end of your cable, and the female will be installed at the bottom. This ensures your sensor box will hang off the ground and away from dirt and debris when its hanging from the power post.
  10. Follow the color scheme shown and be sure to tighten everything with your screw driver. For our cable we followed the following standard for 50amp service. Black (110 A), Red (110 B), White (Neutral), bare copper (ground).  Take extra care to ensure no wires are touching each inside the Camco male/female plugs and be sure your male & female ends are identical at each end. If they are touching anywhere or you’ve mixed up a wire you’ll be popping breakers trying to isolate the short later so take your time!
  11. Once you have your ends installed, you now have a functioning extension cable with Efergy sensors installed midway down your wire. Congratulations!!
  12. Take care to install your Efergy wireless sensor into the box, attach the 3.5mm ends from the sensors into the transmitter, install batteries in the transmitter and arange everything nicely in the box so that it closes without pressing the button on the front of the transmitter. Close everything up and your almost there.
  13. Now its time to use that silicone listed in the materials list. Apply a liberal amount of it around the rubber grommets entering your sensor box. This will ensure you keep that water out to avoid damaging your sensors.
  14. Thats it, you did it!

Additional Photos:

Testing Cable:

While circuit breakers exist for a reason, they may pop too late or not at all (in very rare cases) causing damage to your rig. Before you use your cable we recommend using a multimeter to test your cable. Here is a link on testing extension cables that will come in handy if you’ve never done this before.

Using your Energy Monitor:

Now that your cable is ready and tested, its time to install it. Its just like any other extension cord, so start by plugging the male end into the power post (breakers off) and the female end into your RV’s main power feed. Then you can flip the main breaker and your up and running! Your Efergy sensors come pre-paired so they should start picking up immediately but if they don’t follow the instructions provided by the Efergy. We found their support to be great but we didn’t need it much because everything worked well out of the box.

Have ideas on how to improve the design or thinking of taking on this project? Make sure to mention it below!

Your comments keep us going and we love hearing from you!



  1. Hi question for ya. Right now, we have 3 rvs hooked up to regular electric coming from the pole, same meter. Right now it is at $306 per month. 2 have 30 amp and the 3rd has 50amp. And of course there is an discussion over amounts that should be paid. I think the 2 30amp rvs should pay less then the 50amp. What are your thoughts?

    • Hey Charlie, the hookup amps or wire has little do do with how much power the person is using over the course of a month. You can however add power meters inside your boat or rv inside your primary electrical panel which will calculate your usage and also multiple that into $$ based on the per kwh charge on the electric bill. Most meters can display on a smartphone or small screen and tally usages hourly, daily, weekly, monthly. Then you can let the other two folks sort out the remaining balance.

  2. Ronald A Brown Says: September 26, 2018 at 4:08 pm

    any update to this since 2015?

  3. So if I only have 30 amp into the trailer, I could monitor the AC power with one clamp and say the solar with the other clamp??

    • Hey Mike, a 30 amp service has 1x 110 hot leads that would need to be monitored so i suppose if you could figure out how to wire it correctly the system could monitor a second 110 AC hot. That said, a solar system would be a DC system so i doubt it would work with the monitor (you’d use a different type of monitor to monitor solar and its usually included in your solar charge controller as well). Hope this helps answer your question and sorry for the delay!

  4. Did this project with 10/3 (10 gauge wire. 1 black, 1 white, 1 green) for my 30amp RV. Except for the efergy I bought all materials from Home Depot. from start to finish 1 hour approx. $35.00 Will see how it works in the RV, I tested it out on a 30 amp receptacle that I plug my RV in using a 30amp to 15 amp reducer. and I plugged in my home air conditioner and it started measuring right away. The range of communication is more than 200 feet. THANK YOU FOR THIS IDEA

  5. Rouel Fernandez Says: April 15, 2018 at 3:07 pm

    I know this has been here for a while. DIY projects are awesome, but some times an alternative can be handy. This may do for some:

  6. Ed CHEENEY Says: October 30, 2017 at 10:02 am

    Hi Eric, Grate project and video, Thanks so much for the help.
    Today Efergy has two models for sale the “Elite true power meter” and their
    “Elite Classic” Elite True costs $30 more, but I am not sure of the difference. What would you suggest.

  7. Ron Snipes Says: July 4, 2016 at 6:39 pm

    I know this is an older post, but I have a question. You put a sensor on each of the “hot” lines, red and black, so does the meter read each one separably and record the use, or both at the same time? Just wondered because I know how they feed the panel. I have two RV’s hooked up to my house, one on a 30 AMP line and one on a 50 AMP. I want to meter each so I know which is drawing the most current whenever we have family staying in them, sometimes for a month or more at a time. I bill shoots up when both are in use and I want to know which one is using the most. Thanks.

    • Hi Ron,

      The Efergy monitors the two hot 110v lines that make up a 50amp RV services at the same time. I suppose if you took one sensor off it would monitor a single line independently. It adds each together internally to give us a total. For your purposes, might be easiest to either buy two Efergy units if you want to record them separately or connect to the main feeds of your house which will give you a combined reading of all power usage (which you could then subtract the amount your power bill normally is without the RV’s to give you a general number as to how much power the RV’s themselves are using). Best of luck and glad we could help out with our article. Let us know if you have any further questions!

      • Ron Snipes Says: July 5, 2016 at 1:19 pm

        Thank you, good advice. I thought about getting two meters, but was concerned because of the new wireless meters. The sensors send a signal over a specific frequency to the meter. If I had two of the meters, each with their own sensor, but using the same frequency, how would I know which signal each meter was getting. Thought about getting two different brands so they would not interfere. Thanks for you help!

        • Thanks Ron, thats a good point. I would call Effergy. Since the box states that it supports up to 4 meters on one device, and the device uses a pairing sequence i think that you should be safe from it picking up another signal but i would be very curious to see what you find out. I’ll make sure to mention it the next time I call them too. Thanks again!

  8. Bert Fernandez Says: February 4, 2016 at 2:45 pm

    Couldn’t you install those sensors at your RV panel instead of installing them in that box outside? I like the set up and am going to look into this for my own RV. I’m a licensed electrical contractor in Florida so if you ever have any questions don’t be afraid to ask. Im going to look into this system right away. Nice video by the way I was going to comment there but it was locked out.

    • Hi Bert. You could install at the panel in your RV but then it would pickup additional power either provided by your generator or by Solar (depending on your setup). That may be what your looking for but for us we were looking to monitor only what we were taking from the campground since that’s what we were being billed for. We also wanted the solution to be portable since we have friends and family who borrow the setup from time to time. Best of luck and thanks for checking in!

  9. No worries Rich, The wifi Ranger Elite (pack) is the one i’m talking about. You need the kit that contains the white Go2 router as well as the exterior wifi antenna. Here is a link to the product. – Its more expensive but less than a elite and br1 would be. To support two cellular carriers you’d need to have an ATT/Verizon USB cell stick and swap them manually.

    Answering your second question as to using the BR1 & Wifi Ranger. The issue with the BR1 and Elite combo is that you need to configure the Elite as a WAN source as you stated. You then need to plug it into the WAN port of the BR1 which would basically turn it into an internet source (like any cable modem etc). That’s fine and it works well when you do that but the issue is that you no longer have access to the management interface of the Wifiranger.. The management interface is used to select which wifi you connect to on the wifi ranger. This means when you move campsites, you can no longer tell the wifi ranger what wireless to connect to. Thats not the end of the world though, you can still get to the wifi ranger but you need to connect to it via the wireless interface (bypassing the BR1). It works but as i said its a bit techie lol. Shoot me a personal message on our facebook page and we can setup a skype call and i’ll explain things more, its a bit tricky to understand. i can also show you the rational I have for recommending both systems. Glad to continue the convo!

    • Rich Thibodeau Says: January 14, 2016 at 3:56 pm

      Thanks again for helping me through this decision! I often feel more assured speaking with an experienced user than a manufacturer’s support person (sadly) However, in this case I emailed WiFi Ranger Support and heard back quickly from Evan with a straightforward, clear unequivocal response. He confirmed that the Elite could be connected as just a WiFi WAN source as we’ve been discussing. I guess now we’re just considering the other end – the Br1. So I guess from what you’re saying that the WiFi Ranger Elite integrates with tWiFi Ranger’s own router in such a way that you can easily access the WiFi management interface, but not so much when it’s connected to “foreign” hardware like the Pepwave? If that’s the case, then I’m guessing there must be some configuration to do on the Pepwave to be able to access the WiFi Ranger’s embedded interface. Unfortunately I’m not on Facebook any longer, so I can’t message you there… but I think you may be able to locate me through Google+ if you have an account? In any case, I have configured firewalls and routers (SonicWall, etc) multiple times. I may be able to figure it out. Sometimes just knowing it can be done is help enough!
      I really appreciate your patience and help.

      • Hi Rich, sorry for the late reply, we were out this weekend. If you have firewall experience that is great, that will go a long way here. shoot me an email at and we’ll setup a call to further explain. Looking forward to chatting!

  10. Rich Thibodeau Says: January 12, 2016 at 7:35 pm

    This is a great idea. I searched and couldn’t find a portable KWh meter of any kind elsewhere. I mean, there’s the “Kill A Watt” but that would never handle a 50 Amp load (can you imagine?) One question: Is there any reason not to place the sensor/transmitter box at the inboard end of the cable rather than outside where it could get “lost” somehow?
    Just FYI – based on your other video re: campground WiFi and the Pepwave Br1 router I will be adding them to the mix as well.
    Thanks very much for sharing your expertise and experience! Looking forward to more!

    • Hi Rich, we had the same problem. Seems nobody had a solution and half the campgrounds we visit seem to just “guess” at how much they should charge you. Just telling them you have a meter seems to cut the overcharging and strange bills we used to get to be almost nonexistent… I don’t see any reason why you couldn’t do this inside your coach at the other end of the cable. For us we have a 50ft power cable on a electronic retractable winch so we’d be doing some major surgery to our RV to put it on the other end. We also wanted the solution to be totally portable and interchangeable if we ever sold ou coach so that’s why we came up with the extension cord idea. Regarding the Pepewave, its a really great solution if your looking to rely pretty much solely on cellular. Now that we are learning even more we’ve started recommending the Wifi Ranger which you should also check out. Its not as strong as the Pepewave in some areas (it only supports one cellular connection, not multiple) but it is stronger at picking up campground wifi/public wifi as an alternative internet connection. WIfi Ranger sent us their products to review and we are still in testing but so far they are pretty good. We’ve put a couple in for friends and they are happy. Make sure to check those out too and if you need a discount code for their website we have one. Stay in touch and safe travels!

      • Rich Thibodeau Says: January 12, 2016 at 9:03 pm

        Many thanks for your reply! I was aware of the WiFi Ranger – and having looked at it again it appears to be the most powerful WiFi transceiver available. One question arises – couldn’t the WiFi Ranger be used together with the PepLink Max Br1? I think of connecting the WiFi Ranger Elite in bridge mode (just to provide powerful WiFi) and relying on the PepLink Max Br1 to provide AT&T / Verizon options when free WiFi is just not available or not good enough. I ask because I really need to keep as many internet options open as possible as I need to stay connected for 8-10 hrs a day as a remote sys admin. I will be taking to the road full time sometime between April and June depending on when I’m ready to roll. Your thoughts would be greatly appreciated!

        • Hi Rich, yes you can technically connect the wifi ranger’s external wifi antenna with the BR1 but its going to be a very “techie” solution. Since they were not designed to work together getting the Wifi ranger to act as the “internet source” for the BR1 will be tough. Don’t get me wrong, we’ve done it and it works, but its not really ideal in my opinion. One thing to consider (that i think Wifi Ranger does a bad job of explaining) is that the Wifi Ranger does have a powerful wifi transmitter/receiver as you said but it also has a Cellular WAN port (USB) which means it will also use cellular like the BR1. This combined with an optional cell booster kit would give you a strong wireless and strong cellular internet connection. The wifi ranger then allows you to select from cellular or wifi connection all from within the web interface letting you quickly adjust your connection based on what your locations best options are. The BR1 does pretty much the same thing, but its wifi transmitter/receiver is much weaker that the WifiRangers (but the BR1ls cellular modem is a bit better). There are trade offs of both. What i would say is that for anyone with only one cell provider (i.e. only att or verizon/spint) the wifi ranger is probably a better all around solution since it will do just about everything and also come with some top notch tech support from people who understand what RV’ers are trying to do. If you have multiple cell connections (we have att and verizon) then the BR1 gives you a better change at being “always connected” but that comes at a price with much higher cell data charges. We are here to help continue the discussion. Best of luck!

          • Rich Thibodeau Says: January 13, 2016 at 9:45 pm

            Hey Erik, I appreciate your patience and willingness to help someone up the learning curve! I checked the WiFi Ranger Elite, and it doesn’t mention anything about cellular, so I can only assume it’s not the WiFi Ranger product you’re referring to? If so, it also has an ethernet port (aside from the POE port) that an online doc says can be toggled between LAN and WAN. So I’m thinking that it might be possible to run an ethernet cable from the WiFi Ranger Elite down to the WAN port on the BR1, thereby incorporating in the one router the best WiFi option together with 2 cell data options. I don’t believe I’ll be able to attain connectivity full-time without using 2 carriers plus WiFi for whenever that is available. The problem is I haven’t purchased the equipment and I’m not finding enough documentation online. I guess I should contact WiFi Ranger directly… and once I get an answer I’ll post it here!

  11. Great project Erik!
    A couple of possible changes…

    * Use 6/4 SOOW instead of 6/3, available at most Home Depots. This will give you:
    – A more flexible wire (it’s what RV 50amp power cords are made from)
    – A fully insulated mechanical ground (to avoid that bare mechanical ground running around the hot legs to the top of the male plug)

    * If you want to log usage on a PC for later graphing, etc… You could use a Z-wave power monitor. Something like the Aeon Labs DSB28-ZWUS.

    Keep up the great posts!

    • Awesome suggestions Mike, sorry we missed your reply, somehow it slipped through and we didn’t see it until now! Thanks for the support!

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