Electrical Protection/Surge Arrestor

It all started with conversation around the “campfire” with some of our RV group. I happened to notice that one of our group had an Electrical Protection/Surge Arrestor device on the end of his power cord. He stated that he had found some bad power in the past so with his new fifth wheel he did not want to take chances. Another of the group with a relatively new Entegra stated that his had come from the factory with one. The discussion them turned to whether hard wired or portable was better. The ones with portable stated that if it malfunctioned, they just took the unit off and plugged directly into the Park RV outlet. The hard-wired ones stated that they could by-pass theirs. Of course, my wife looked at me and asked, "so which kind do we have?" Well, in the almost 30 years we have had RV’s, we have never had one. It was always on the list, but never got close enough to the top to do anything about it. I did not know which flavor I would want, hard wired or the portable. Needless to say, an electrical protection device/surge arrestor went to the top of the RV to-do list.

So I looked at what was available on the market. The two biggest names are the Progressive Industries EMS RV Surge Protector and the Surge Guard RV Surge Protector. CAMCO also has a Power Defender/RV Voltage Protector, however I found more information on the first two.

After looking at the specifications on the two brands, I choose the Progressive Industries EMS-HW50C. In the literature it specifically lists protection against accidental  240V, and the connections are not exposed.

Next thing was to find the best price. Multiple RV Parts and Accessory stores sell them. I finally settled on Tweety’s RV and Truck Accessories. No shipping charge was a bonus. One thing I will say is that Tweety’s marks everything with their logo. So when you get the unit, you might not realize what it is as the box carries a lot of Tweety’s markings.

 

The installation is pretty straight forward. You connect your power cord to one side and the transfer switch to the other. Easy Peasy, as some would say. But, there are a few things that I found that might make your installation quicker and easier.

First thing, location, location, location. Where are you going to install the unit. It is nine (9) inches long, five (5) inches wide and is four (4) inches deep. It needs to go into the electrical box, close to where your shore power cord enters the Automatic Transfer Switch. It should not hamper the storage of the power cord and it should not be close to water, or anything that might damage it. In my electrical compartment, the shore power cord coils and lays on the bottom of the cabinet. I simple held the box in several locations until I found one that would work.

My electrical cabinet also includes the converter/charger and one of my inverters. In the same cabinet are breakers for various DC related items, the slides and the like. My chosen location was away from these breakers and ended up on a side wall under the inverter. There is some discussion on where the EMS Box should be placed in the electrical system. Should it be on the shore power side of the ATS, or be between the ATS and the load center (breaker box). Putting the EMS Box between the ATS and the load center would protect you from a generator that provided over voltage, or a hot ground situation and the like. I placed mine on the shore power cord side, as the RV pedestal is the most likely candidate for getting “bad” power.

The instructions are pretty self-explanatory. Turn off all electrical power to the motor home, including the generator. You do not want to accidently cut into a wire, or take the cover off the transfer switch if you have any electrical power going through the power cord or into the transfer switch. I then held the EMS box to the side wall where it would “live” and used a spring-loaded center punch to mark the hole locations. I drilled 1/8 inch pilot holes, then used #8 by 5/8 self drilling sheet metal screws to anchor the unit to the side wall.

Instructions suggest disconnecting the power cord from the transfer switch, and cutting a length off of the power cord to make the connection to the EMS box. You could also, if you choose to go this route, simply cut your power cord, allowing enough length to get to the EMS box. No need to disconnect it from the transfer switch, or even needing to take the cover off the transfer switch.

Photos before anything was disconnected.

I disconnected the shore power cord from the shore electrical outlet and from the transfer switch. I did not want to give up three feet of power cord length. Might not seem to be a lot, but it also might be just enough that you would not need an extension cord.

Insides of the Progressive EMS

For the side going to the transfer switch from the EMS Box, I sourced some 6-gauge flexible (welding) cable through Amazon. I used flexible 8-guage for the ground wire. Since the cable came in black and red, I used colored tape on black cable to indicate the neutral (white) and the ground (green) wire. I had red and black sheathed cable for the other two connections. I then made the connections on the outbound side of the EMS box. The outbound red and black cables go through pick up coils. The black cable uses the green coil and the red uses the black coil. There is a small arrow on the face of each coil. That arrow (coil side) must be toward the center of the EMS unit to work properly. Again, I used the clamp on the entry side of the EMS Box to secure the cables. I then routed the other end to the ATS switch and made the connections there.

Outbound (to Transfer Switch) connected

I ran the shore power cord through the wire clamp, then connected the power cord to the inbound side of the EMS box. There is a wire clamp provided for each end of the EMS box. I used the existing strain relief clamp on the shore power cable, just relocated it to a different spot. 

Inbound and Outbound connected

Again, these are straightforward, but I always take pictures before I disconnect anything so I have some idea how it should go back together. 

Inbound connection (from Progressive EMS) in center.

 The cables were tied together with plastic wire ties and then anchored to the side panel of the electrical compartment.

Inside the EMS Box there is a jumper that sets the duration from the time the EMS Box is energized to the time it makes the connection and starts providing power. Factory default is 15 seconds. I removed the jumper making it 136 seconds (about 2.25 minutes). This timer is to allow for the HVAC compressor to reset before power is sent to the coach. If you use this long timer, it can be somewhat disconcerting when you plug in the power, see the voltages on the two “hot” legs of the circuit, but you are not getting power to the motor home. Just wait. 2.25 minutes seems like a long time when you are waiting for something to happen, then CLUNK, you will hear the EMS Box make the connection to the transfer switch and you have power inside the motor home.

I mounted the monitor unit next to the EMS Box. There is a lot of cable and I may, at a later time put this monitor inside the motor home. Or, as some suggested I might get a second monitor and splitter and put one inside the motor home and leave one where it is at. The monitor allows you to see immediately the electrical quality when you plug the shore power cord in to the pedestal. The remote also has a switch allowing you to by-pass the EMS Box in the event of a failure. The other nice thing about this EMS Box is that everything inside is modular, so if it fails, the manufacturer will simply send you a new board to replace the one that failed.

Monitor/Switch to the left

One piece of advice – find where you want to mount the EMS Box, drill the holes, screw it in place, check your clearances, then remove the box and make the connections. It would have been far easier to make the connections looking down on the inside of the EMS Box then trying to crawl part-way into the cabinet and make the connections with the box on the side wall.

There are several tutorials on the web on the installation of an Electrical Protection/Surge Arrestor device. Motorhome Magazine recently had an article on these devices. Just about any RV Forum will have multiple entries on it, and the folks at Wheeling It have both a blog post and a YouTube view on it. A link to their site is below.

http://wheelingit.us/2017/01/23/rv-surge-protectors-protecting-the-beast-against-bad-power-surges-with-ems-hw50c/

So the “campfire” discussion lead to the installation of a electrical Protection/surge arrestor device. Just one more thing off the list. I’ll be moving to the next item shortly.