Which EMS Surge Protector

[Sandy___Shirley]

Just got our RV back from the repair shop! We had a 5th wheel for 10 years then changed to a motorhome 5 years ago. We had our first electrical failure in October. The Surge, or whatever, fried our inverter and the circuit board that ran the heat in our bedroom. The cost was over $1,000, but only cost us the $100 deductible on our insurance.

We made our first post on this on 10/6/20 and have been doing a lot of research since then. One possibility was the hardwired Progressive EMS-HW50C. Then we started thinking about the post mounted EMS-PT50X so that we could check out the campground wiring before pulling out the extension cords.

After further research we have added the Southwire 34951 to the list.

As we understand it, the Progressive units have been around for about 10 years, so there are a lot of posts about them. The Southwire 34950 has been around only 2 or 3 years, so far less posts, and the 34951 is the new upgrade that includes a remote Bluetooth monitor.

There is a TechnoRV article that does a good job of comparing the two units:
Do you need an rv surge protector

If we understand our research so far, both post units are about the same, Southwire costs a little more, Progressive take about 2 minutes to analyze the power while Southwire can do it in 10 seconds.

A big question to the group is: TechnoRV gives their gold star to the Southwire unit, does anyone know if the two companies are in any way related?

And of course; what are your opinions of the two units? Progressive EMS-PT50X vs Southwire 34950/34951

[time2roll]

pianotuna wrote:
The absolute lowest voltage I've seen is 100.

I have seen the low 90s one time. Too low even for my 16% booster to correct. No cool air until the sun went down. I felt bad for the others that had no idea. Brand new place too on the east side of Glacier.

[pianotuna]

Lynnmor wrote:
In addition to the above post, an autoformer will have your appliances running with voltage that is closer to the optimal so the appliance will be more efficient.

I love getting full wattage from my electric heaters in the winter.

[pianotuna]

time2roll wrote:
The power is evaluated immediately and continuous. The Progressive does have a two minute delay to verify power is stable before the switch closes. Also the delay will be restarted if there is temporary problem. This prevent your air conditioner from an immediate restart if the issue is only for a split second.

This is one thing my system does not do--but I can get around it by using load support on the inverter/charger. It is one reason I want such a large bank of truly deep cycle batteries.

[time2roll]

Sandy & Shirley wrote:
Progressive take about 2 minutes to analyze the power while Southwire can do it in 10 seconds.

Not exactly. The power is evaluated immediately and continuous. The Progressive does have a two minute delay to verify power is stable before the switch closes. Also the delay will be restarted if there is temporary problem. This prevent your air conditioner from an immediate restart if the issue is only for a split second.

From the manual:

Time Delay for A/C Compressor: If AC power is interrupted or the EMS detects a fault condition, the built in time delay is activated. There are two settings on the EMS: one is 136 seconds (02:16), and the other is 15 seconds. Consult your air conditioner manual to see if it has a time delay built in. If so, use the 15 second delay, if not, use the 136-seconds delay. The factory setting is 15 seconds.

https://file.powerprodllc.com/-/media/inriver/ZX480.pdf

Certainly if the voltage is moving just above / below the cut-off point you don't want all your electronics to be cycled on-off every few seconds until you unplug them.

[Lynnmor]

In addition to the above post, an autoformer will have your appliances running with voltage that is closer to the optimal so the appliance will be more efficient.

[pianotuna]

An autotransformer is a different beastie than an autoformer.

Mine has 3 levels of boost and one of buck. Thanks to Mex it is also equipped with surge which is far more effective than the mov's in the much more expensive units in this thread.

I' also point out that ANYONE who has a hybrid inverter/charger with load support has a unit with an autotransforer.

As for the "ruling" it has no force in law.

As for campgrounds--they do not understand that using an autoformer doesn't 'steal' power from other campers. If I connect to a 30 amp outlet the autoformer does not allow me to use more than 30 amps.

For example an air conditioner.

Mine, on a hot day, draws 1900 watts. Let's say I'm running the fridge too, which is another 325 watts.

That totals 2225 watts.

2225/120 = 18.5 amps.

Lets say the park, through no fault of their own is only able to feed 90 volts.

2225/90 =~ 24.7 amps

So I am still 5.3 amps below the 30 amps that I have purchased.

Ah but--the autoformer is not 100% efficient. It does approach 99%--but I'll use 98%.

24.7/ .98 = 25.2 amps. So I'm still well below 30 amps.

The absolute lowest voltage I've seen is 100.

In actual use, I choose to limit my load to 24 amps. I use load support for any extra draws.

I also have solar which reduces my "foot print" to the campground by about 1000 watt-hours per day.

[Sandy___Shirley]

pianotuna wrote:
Far more damage is caused by low voltage than surges. I'd go to the fully featured Hughes autoformer with surge protection.

Be aware that there is some controversy surrounding RVs and the use of autotransformers. The National Fire Protection Agency (NFPA) stated a ban on the use of autotransformers due to the dangers they place on the campground’s electrical service. NFPA Code: NFPA 70 Article 551.72 (E,F) states, “The use of autotransformers shall not be permitted. The use of listed surge protectors shall be permitted.”

Many campgrounds already ban the use of autotransformers, and more could do so in the future as a result of NFPA 70. If you have an autotransformer, sometimes referred to as an autoformer, it may be a good idea to ask the RV park that you are staying at if it is okay for you to use it at their facility.

[Sandy___Shirley]

Lynnmor wrote:
I suspect that the damage you experienced came from a loose connection and not a "surge." All kinds of things are blamed on surges but in reality they are rare.

Actually, the day it happened at the campground the power went off twice because of a large accident on the road near the campground. Those in our group who did have surge protectors did get reports that there was a surge on one of the two times the power was restored and the inverter did not keep our frig working on the way home from that trip. We noticed no heat in the bedroom 2 trips later.

[Lynnmor]

I suspect that the damage you experienced came from a loose connection and not a "surge." All kinds of things are blamed on surges but in reality they are rare.

[2naEagle]

The Hughes Power Watchdog is anuther one you should give consideration. It has a lot of very cool features.

[wa8yxm]

We made our first post on this on 10/6/20 and have been doing a lot of research since then. One possibility was the hardwired Progressive EMS-HW50C. Then we started thinking about the post mounted EMS-PT50X so that we could check out the campground wiring before pulling out the extension cords.

After further research we have added the Southwire 34951 to the list.

First they both have been around longer than 10 years.. Not sure how long but at least 15 (When Got my RV) both were out long before that.

For most of those years Progressive Industries had the best (Limited lifetime) warranty and TRC (not then Southwire) 1 year.

When Southwire bought TRC they went Limited lifetie

Hard wired or Portable
Hard wired you never forget it and it's outta sight outta mind for the sticky finger crowd. Though I've never heard of one walking off. Still much harder to walk off with a hard wired...

The Southwire/TRC hard wired is easier to install.. But not that much easier

I used one. still have it in fact. no longer have the RV (For reasons complex I converted it to a plug in model but that was due to how or rather where I installed it the plug/outlet needed already existed)

Oh as for checking the park power before you connect.. IF park power is not "Up to spec" the hard wired won't connect you.

[pianotuna]

Far more damage is caused by low voltage than surges. I'd go to the fully featured Hughes autoformer with surge protection.

[Tom_Barb]

ORbiker wrote:
I installed the hardwired Progressive EMS-HW50C in our 5th wheel. It analyzes the power coming in about 20 to 30 seconds.
If the power is not correct in some way it will not let it pass.
If for some reason the monitor went bad, there is a switch on the remote to let the power bypass the unit.
So far ( 3 years ) it works correctly and seems to be a great product. KEN

US too. 3 years trouble free.

[ORbiker]

I installed the hardwired Progressive EMS-HW50C in our 5th wheel. It analyzes the power coming in about 20 to 30 seconds.
If the power is not correct in some way it will not let it pass.
If for some reason the monitor went bad, there is a switch on the remote to let the power bypass the unit.
So far ( 3 years ) it works correctly and seems to be a great product. KEN