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Midwest Greg 04-06-2020 09:30 AM

Surge Protector: Internal vs. External?
Hello all
Just joined and we'll be ordering our new Airstream hopefully this week.
Trying to decide if an internal or external is the way to go on surge protector. A little nervous if there's a huge power spike (lightning strike, etc?) may fry an internal unit causing issues and/or access for repair replacement of componentry?

Dealer will include SP of my choice and install if I decide on an internal unit.
Thanks for any help.


lsbrodsky 04-06-2020 09:45 AM

I won't try to influence your choice as you will see both used and liked. Just don't let anyone tell you that you need the internal model to see operating parameters. I have a Southwire external and it communicates via Bluetooth to an internal display.

wulfraat 04-06-2020 09:49 AM

I like my external one. Progressive Industries - it not only protects for surge but also low / high voltages, etc..

Has an LED display that shows you current / voltage on each leg, plus any fault information. If it were to fail I am not stranded without 50A shore power, I just plug into the pedestal without it.

ROBERT CROSS 04-06-2020 09:55 AM


Can be used other than with the AS, plus if it does get cooked it's easier to return for re-build.👍


journeydog 04-06-2020 10:37 AM

FUNCTION: Both the same

THEFT PROOF: Internal is tougher to steal but, nothing is really theft proof.

(I have an external with cable lock - a hefty cable/lock cutter will negate the "theft-proof" status - if they really want it, they'll get it.)

If your dealer is offering to install a "free" internal, I'd go for it.

Squairstream 04-06-2020 10:39 AM

Sticky Fingers Protection
One benefit that I have found for the internal hardwired m,odel is that I do not habe to worry about someone having "Sticky Fingers" borrowing it.

moosetags 04-06-2020 10:40 AM

Greetings from the Florida Panhandle
Hi Greg. I would definitely recommend the external unit. If an internal unit trips, you may end up dead in the water if it cannot be reset. With the external unit, you can just find another power source and plug in directly.


drbrick 04-06-2020 10:45 AM

IMHO the external unit is the way to go ... you can secure the unit to prevent it from "growing legs". If it trips or blows can be easily replaced etc.

dhroberts 04-06-2020 10:49 AM

I am a fan of the Progressive Industries external unit EMS PT50X. I lock it to the campsite's power pedestal. Easy. Not really certain where I would put an internal unit in my 30' 2016 Classic had I gone that route. Have not had a need to read the monitor remotely via bluetooth, etc.

Adventure.AS 04-06-2020 10:57 AM

All of the internal units that I have seen hum when in operation. If you have a FB model this could be annoying when trying to sleep.

Pat Pierce 04-06-2020 11:07 AM

We had an internal one installed before picking up the new AS at the dealer. Out of sight, out of mind, why not? But they never told us about the things we would experience, thus some consternation I had before finally learning. For instance:

1. When connecting to shore power, or to a generator - it takes seemingly a minute or more before you will hear a clunk which is the sound of the SP approving the power. Lights on!
Sometimes it seems forever! Just relax. It took me too long realizing the delay is just the SP checking things out.
2. The SP at least in our case was installed behind the power panel. So, to see what is happening with it, one has to remove the power panel. Ugh.
3. One other thing, and it relates to the Camco power cord dog-bone adapters. I do not recommend these at all! The ground pin is horribly defective. My first one broke off and I did not realize it had, but after much grief in why my SP was seemingly not working, I found the ground pin was missing. Stupid me I bought another one so I could get power back. It wasn't long before the pin broke on that one. Looking the pin over, it is so poorly manufactured - do not buy. Harbor Freight sells a really nice dog-bone, well made for what $6. I bought two. Impressive.

jcanavera 04-06-2020 11:12 AM

I went with the external unit also. I carry a separate locking device to keep it from easily being lifted although nothing is foolproof. After a lot of comparisons I settled on a Progressive Industries EMS PT30x. I chose it specifically because of it's warranty both on normal usage and the fact that Progressive will also replace or repair it if it sacrifices its life saving my trailer. Not all lifetime warranty units are under warranty once they give up their life on a surge. It pays to read the warranty fine print when you shop. There are other lifetime warranty units out there, but in their warranties they tell you that the warranty does not cover the unit giving up its life due to voltage surges. So in those cases they did their job, but now you have to buy a new one.


Silvr_Bullet 04-06-2020 11:18 AM

Worth noting, the Progressive Industry EMS has a lifetime warranty, good because these units run a few hundred dollars. I tether mine with a cable and lock to the campground pedestal, best case is it makes stealing a little difficult.

drbob46923 04-06-2020 11:22 AM

Surge Protector
We have a hard wired surge protector installed under the refrigerator behind the breaker panel. My only comment is that if you get the "hard wired" model you SHOULD ALSO HAVE THE REMOTE DISPLAY INSTALLED - they are inexpensive and easily allow you to easily monitor line voltages, amp usage, and faults. I installed the remote display a few years ago - simple
straightforward install. Also, makes it easy to track how much current each appliance uses when plugged into shore power, if you like to keep notes about that sort of thing, so when you are plugged into 15 or 20 amps at a small campground you will know exactly what you can run.

Cyclist 04-06-2020 11:22 AM

We've had the Progressive Industries external unit for over five years with no trouble at all. It even shut down once to protect us and the AC from low voltage. I have no experience with the internal model.

DonRich7878 04-06-2020 11:25 AM

I installed an internal model EMS-HW50C from Progressive Industries with a wired remote control & display. Works flawlessly, comes with life time warranty. In 5 years use has tripped twice due to power issues that potentially could have damaged the trailer electrics.

The unit has a "by pass" switch on the control unit, but only use it if you are confident that the detected fault causing the unit to trip, wont damage anything or cause a safety issue.

An internal unit properly installed will add value and convenience to your rig. The only reason I can think of to use an external surge protector is that if you have more than one trailer and share the unit between them.

Be sure to select a UL rated system, no matter which way you go.

banderabob 04-06-2020 11:32 AM

We have an “outie”, a simple one from Camco. We had a Progressive EMS but found when used in tandem with a voltage regulator (which we bought for a 2 month México caravan) we had continual on-off cycling. Were I considering a new unit, I might consider installation of an “innie” voltage regulator to deal with low voltage situations.

Beewee 04-06-2020 11:55 AM

Surge Protector
We had the Progressive Industries HW50C Hardwired EMS Surge & Electrical Protector (50 Amps) installed when we bought our 27 FB Sterling. I absolutely LOVE having an internal unit. Contrary to previous post there is NO lag time when hooking up to power. The display unit was mounted above our light switches right inside the RV door, making viewing easy from say, the dining table. It has saved our butt a number of times, including identifying a reverse polariry issue, which the RV park corrected later. To override the system, you simply turn it OFF. Power then works, but is NOT protected (or recommended).

I saw it on Amazon today for $325 - worth every penny.

Midwest Greg 04-06-2020 11:58 AM


Originally Posted by Midwest Greg (Post 2348358)
Hello all
Just joined and we'll be ordering our new Airstream hopefully this week.
Trying to decide if an internal or external is the way to go on surge protector. A little nervous if there's a huge power spike (lightning strike, etc?) may fry an internal unit causing issues and/or access for repair replacement of componentry?

Dealer will include SP of my choice and install if I decide on an internal unit.
Thanks for any help.


Would also appreciate any brand recommendations...

Sport 16 STL 04-06-2020 11:59 AM

30 amp progressive internal. A little over a year, tripped once, I have remote led mounted at foot of bed. Zero humming noise. There is enough to worry about hook ups, one less thing if it is internal.

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