Surge Protector

Every so often you come across a blog or forum post where a trailer owner describes a serious problem they have had with their electrical system, and usually it involves a problem with a campsite power post or electrical surge. Some of the stories are pretty wild, where a miswired electrical outlet or power surge has fried a bunch of gear in the trailer. These writers have then quickly become huge advocats of surge protection. We have run into a few dubious power posts ourselves, one time the entire 30amp outlet had been ripped out of the box and was just hanging there. That was an obvious problem, but how to protect against something that appears perfectly fine, or a surge that comes out of nowhere.

There are a couple of relatively inexpensive solutions that can be used to a least provide you with some information about the power post you are about to connect to. I have used a Kill-A-Watt meter and a polarity tester, connected to a 30 amp pigtail, that will give you an idea of the line voltage and polarity, but that's all it will do. It helps, but it's not the same as protection.

I started doing a little research into what is available for surge protection, and I soon discovered that anything listed as a surge protector, does just that, protect against surges. There are however, a number of other electrical issues that can cause you problems. To protect against these, you have to step up in features and look at electrical management systems (EMS). These cover surges, as well as low/high voltages, polarity, AC frequency, open neutral, etc. Naturally, this comes at a price, with these units easily topping $200. Some surge protectors will protect you from improper wiring, generally with a warning, but few will shut down the power completely. When you look at the investment made in a trailer, the cost difference between a basic surge protector and a more comprehensive EMS product seems pretty negligible.

The other consideration is between a portable unit or a hardwired one. A portable is just that, it plugs into the power source, and your cable plugs into it. It can then move with you when you change trailers, or also move with the thief who is looking to score a new one, or make a few bucks selling it. Need to keep this in mind when choosing the portable, and some manufacturers are now putting a locking loop on their devices. As we will never be changing trailers, I decided upon a hardwired model. The install would become an interesting little project.

Of all the manufacturers out there, Progressive Industries kept popping up as one of the best. They have a variety of models with all sorts of features, at a variety of price points. It was though, their evident pride in the quality of the product that impressed me the most. They manufacture in America, using quality components, and they back up their lifetime warranty with superb service. Many reviews I read provided stories of how they have gone to great lengths to resolve any issues as quickly as possible. Always good to hear. Another interesting feature is the plug and play replacement of the internal parts. If there is a problem, or a component self sacrifices to protect the wiring, you contact their technical support, describe the issue, and if it is an option, they will send you the component needed to get you back up and running. This is a great idea, especially for those comfortable with swapping out internal pieces. I went with the EMS-HW30C, a 30 amp model, with a remote display panel.

Now is as good a time as any for my usual little disclaimer warning. If this sort of project is not right up your alley, do not attempt it. You are messing with the AC circuits of your expensive Alto...connect something wrong, dislodge a wire somewhere, and you could cause serious damage to yourself, or the Alto. Use a portable model instead, or find someone competent to install a hardwired version for you. If you also happen to be still under warranty, well, that is yet another consideration.

Where to put it? My goal was to just splice it into the main power line, to avoid running a new cable, but this means creating some extra slack to allow for the connections. Not many places where this would be easy to do, as a matter of fact, I think there is only one place you can do this, and that is the front wall, just inside the trunk compartment. Physically it fits nicely there, assuming of course that the area is not already occupied with a bunch of caravan mover gear. The main power cable passes by along the lower edge, but now I needed to find some wire slack. I removed the aluminum cover to the front cubby, home to all things electrical in the Alto. Before doing anything but eyeballing, make sure you are not plugged into shore first! I followed the orange cable and discovered that ours had a nice big loop before it enters the distribution box, and figured with a few little changes to the wiring harness, I would be able to free up more than enough to splice the EMS into the line. The front cubby is a mass of wiring, and one needs to plan and be very meticulous when working in this area. On top of this, #10 cable is a bear to work with, and requires a lot of slow patient moves and twists. I soon had a nice loop along the front wall.

Mounting the unit was the easy part, and as always, correct selection of screw length is essential. I tend now to use a punch to create a tiny pilot hole to start the screw, as a drill bit can plow through an Alto wall like butter...and that is a very bad thing. Once mounted, off came the cover, then the cutting of the wire. First confirm everything is as it should be before proceeding. It was then just a matter of feeding the wires and making the correct connections to the terminal blocks, nice and snug. The remote display plugs in using the provided cable, and this can be placed anywhere. Some mount it inside, but it does have a continuously scrolling display of information, which perhaps might be a little annoying after a while. I chose to mount it by the EMS box, visible with the trunk door open, so I can review the information once I plug in the shore power. After that, not really much need to monitor.

Time to power up and see if anything explodes...which I know full well is not going to happen. Pretty uneventful startup. The display comes to life, runs a quick self test, then starts its never ending scroll of info. It cycles through voltage, current, frequency, error codes and previous error codes. Much like the Trimetric, it is pretty cool to see these details, and definitely reassuring to know it is in place. With an EMS, the default behavior in the event of an issue is to cut the power completely off until the problem is resolved. There is though, a bypass switch on the remote display, which allows one to shut off all the advanced EMS protection, other than the surge. They explain that this can be used in the event that something goes wrong with the internals of the device, which presumably is displayed as an error code.

Jumping ahead a bit in time, it has been in use for a couple of trips where we have had services. It has performed flawlessly, its presence relatively unknown to us. I say relative because it does make a typical electrical hum. Loud enough to be noticed inside the Alto, a low grade sort of noise that is there, but not really there unless your mind looks for it...and my mind does. It would probably not bother most people, but it is there. So naturally I started to think about how to muffle the sound a bit, some sort of insulated cover that could be placed over the entire unit. I checked to see if it generated any heat while in use, and it really does not, so a cover is an option. Thinking about materials, I decided upon getting some high density foam, of the sort that is sometimes used for knee pads in kayaks. Our local camping outfitters sells this stuff in a variety of thicknesses, and by the square foot. Perfect. I soon had created a nice soundproof box, gluing the pieces together with contact cement. Perhaps not the most attractive of solutions, but it is out of sight, and most importantly, reduces the hum to a nice silence.

Nice to know it is there keeping an eye on things, if the need arises. As a project, it was certainly doable, but it was a fair amount of work to get it installed, mostly because of the contortions needed to work in that confined front space.


  1. Great idea and excellent work as usual, Jim.

  2. Nice Installation! I have one to install but there's no room at the front of my 1713. I think it will fit under the sink if I mount it vertically and shave an inch off the back left side of the lower shelf. The wire from the outside plug-in would be disconnected and inserted in one end of the EMS and a new section of wire would then be installed from the plug-in to EMS. I hope the noise is not too loud; I don't think it would bother me but the wife might have some issues!

    1. If you have no room there, I gather you must have the caravan mover, which utilizes that area. Finding room is always an issue, and under the sink will be a difficult area to work in. The hum is not really too bad, and you may want to consider small rubber isolating washers under the attachment points.

  3. Great installation tips.
    I am concerned about surge protection before I venture out on my first "real" camping trip with the Alto. (By real I am after getting it home to Ottawa area from Gravenhurst).
    I was wondering if the remote display cable is too short to mount it inside the Alto - some place more easily accessible?

    1. Hi Tom,
      There is plenty of length to the remote display cable to allow it to be mounted inside the front part of the Alto. The front wall below the table is probably best. The readout on that display is a continuous repeating scroll of information, in bright orange. I was not keen on seeing that all the time inside the Alto.

    2. Thanks Jim.
      Also how did you know it was the orange cable the is connected to the shore power plug on the side of the Alto?

    3. It was connected to the shore power input, and goes to the distribution panel. It is the only orange wire in the mix, and is also a heavier gauge, but that fact was not really part of the analysis. With anything electrical, I also double check any decisions I arrive at.

  4. For those who want to know more about the "hum" here is the reply I got form the "tech" at Progressive Industries (caveat - please do not do any of this unless you are competent in electrical wiring):
    "Some humming can be present, because of the 60 hertz alternating current flowing through the unit. Just changing from one power source to another can reduce the volume of the humming. You can reduce the volume of the humming by taking the following steps.

    1. Without power to the coach, locate the contactor inside the main EMS box. Remove the cover and inspect the interior of the contactor for dust and debris. If any is found, clean it out with compressed air. Also locate the black plastic carrier which closes the contacts when the contactor is energized. Rapidly move the carrier in and out several times to free any debris.

    2. The mounting surface can sometimes amplify the hum. Placing rubber

    washers ( Like, flat faucet washers ) between the surface and mounting

    tabs, can reduce the volume.

    If these actions are not successful, please contact me."

    1. Same response they gave me when I inquired. I did the washer thing. If the hum ever got real loud, I would perform the other steps...I kinda see those as the last resort.