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RVing message boards => Tech Talk => Topic started by: banjo5491 on January 22, 2010, 09:42:11 AM

Title: electrical surge protectors
Post by: banjo5491 on January 22, 2010, 09:42:11 AM
Just seen a ad for electrical surge protectors (50 amp and 30 amp) and wondering if they are necessary. If so, can you use a 30 amp with 50 amp service and vice versa.
Title: Re: electrical surge protectors
Post by: Gary RV_Wizard on January 22, 2010, 11:17:18 AM
First of all, be aware that there are plain surge protectors and the more sophisticated power line monitors. Despite a lot of talk, surge damage in RVs is relatively rare. Other power line problems are more likely to be damaging. If you are going to buy one at all, I would recommend a combined power line monitor and surge protection device. These check for high & low voltage, reversed polarity, open neutrals and grounds, etc. as well has damping surges. Some surge protectors have warning lights that test these conditions when plugging in, but an active device that continually checks and acts as needed is a better form of protection.

The device you buy should match the power service of your RV, either 30A or 50A.  If 50A, the protection device uses the same adapter that your power cord would if plugging to a 30A outlet.  A 30A device can be plugged to a 50A outlet using 30/50 adapter, but yo are only going to get 30A through it.

Do you need one? Hard to say. Older campgrounds often have poor quality power and newer RVs with lots of electronics can be susceptible. You hear horror stories and the word "surge" is used liberally but often inaccurately. Basically it's insurance - you probably won't need it, but if you do it is a godsend.  Most power problems could be avoided simply  by checking the voltage and polarity to power outlets before plugging in, which most newer surge protectors now do. If yo did that rigorously, you are probaly ok. If, like most, you lack the skill or interest in doing so, A power line monitor and surge device is  a reasonable add-on accessory for peace of mind.

Most newer high end coaches have such systems built right in.
Title: Re: electrical surge protectors
Post by: tvman44 on January 22, 2010, 02:40:12 PM
Not necessary except in my book and yes you can use a 30 with a 30 amp RV plugged into a 50 receptacle and vice versa.
Title: Re: electrical surge protectors
Post by: afchap on January 22, 2010, 06:13:45 PM
We started out without one, and got one after ac damage that was attributed to "low voltage". Our SurgeGuard monitors low/high voltage (in addition to other faults) and will cut off electrical power if reasonable limits are exceeded. It has tripped several times ... most often for low voltage, and a few times for high voltage (each time I checked the post with a multi-meter to see what the problem was. From my experience over the years, I would not be without one.
Title: Re: electrical surge protectors
Post by: SargeW on January 22, 2010, 06:19:20 PM
Well, I agree with most of what Gary said.  I only point I disagree with is that I have found a much more common problem is campgrounds having low voltage.  Even a campground with normally adaquate power reserves can be tested in the right circumstances.  It is also much more likely that your electronics will sustain damage from chronic low voltage.  Several times my Surge Guard has cut power to the MH when voltage has dropped below the preset safe limit.  Usually it has been summer time and the campground had many large rigs all running their air conditioners on high.  I would rather sweat than pay the bill for a fried AC or refer. 

They seem to be a bit pricey at the onset, but only a small fraction of what it can cost you if you are unlucky enough to be in a campground with a weak or old  power system.   I bought a unit that hard wires into the rig.  It is in play anytime that the plug is in the pedestal.   

Sarge
Title: Re: electrical surge protectors
Post by: SargeW on January 22, 2010, 06:21:26 PM
OOps!  Paul beat me to it.  He is right on!
Title: Re: electrical surge protectors
Post by: Jammer on January 22, 2010, 08:19:09 PM
Just seen a ad for electrical surge protectors (50 amp and 30 amp) and wondering if they are necessary. If so, can you use a 30 amp with 50 amp service and vice versa.

Most surge protectors are just MOVs with a cord and socket.  MOVs -- metal oxide varistors - have the property of conducting electricity like a dead short above a certain threshold voltage and hardly conducting electricity at all otherwise.  They are rated in the number of Joules of energy they can take before they self-destruct.  Back in the 1960s, before we had MOVs, there were gas-filled tubes, which no one uses anymore, except for special applications.

MOVs are mainly effective at suppressing high-voltage transients caused by lightning strikes, which are damaging to sensitive electronics.  Most higher-buck electronics have MOVs built into them for this reason.  The MOVs themselves are usually just a buck or two, maybe more for a really big one.

With the fancy surge protector boxes people sell, you get a plug, a socket, two MOVs (three for 50A service), and a box to hold the socket and the MOVs.  The MOVs are the cheapest part.  You could, quite literally, built a much better one than any that are for sale, for less than they typically sell for, by using great big giant MOVs.

With great big giant MOVs, the efficacy of your surge protection is going to be limited by the AC properties of your grounding environment.

They don't do much for air conditioners or lighting, because they don't do anything to fix the overvoltage, undervoltage, and dropout conditions that pose problems for these loads.  For that you need one of those voltage regulating autotransformers.

I don't have a surge protector on my TT.  Just saying.

Title: Re: electrical surge protectors
Post by: ArdraF on January 22, 2010, 08:30:19 PM
Banjo,

Look at it this way.  There's always a first for everything and the very time you don't have one you'll wish you did!  Murphy's Law at work.  It's cheap insurance instead of replacing damaged microwaves, TVs, DVD, washer-dryer, or whatever.

That said, I agree that many campgrounds have low voltage, especially if they're old and on a full weekend with everyone using their appliances to fix dinner, wash and dry clothes, and all the other things we do that use up a lot of those electrons.  So yes, protect those expensive appliances that surges or drops can damage.

ArdraF
Title: Re: electrical surge protectors
Post by: SargeW on January 23, 2010, 12:44:01 PM
Most surge protectors are just MOVs with a cord and socket.  MOVs -- metal oxide varistors - have the property of conducting electricity like a dead short above a certain threshold voltage and hardly conducting electricity at all otherwise.  They are rated in the number of Joules of energy they can take before they self-destruct.  Back in the 1960s, before we had MOVs, there were gas-filled tubes, which no one uses anymore, except for special applications.

MOVs are mainly effective at suppressing high-voltage transients caused by lightning strikes, which are damaging to sensitive electronics.  Most higher-buck electronics have MOVs built into them for this reason.  The MOVs themselves are usually just a buck or two, maybe more for a really big one.

With the fancy surge protector boxes people sell, you get a plug, a socket, two MOVs (three for 50A service), and a box to hold the socket and the MOVs.  The MOVs are the cheapest part.  You could, quite literally, built a much better one than any that are for sale, for less than they typically sell for, by using great big giant MOVs.

With great big giant MOVs, the efficacy of your surge protection is going to be limited by the AC properties of your grounding environment.

They don't do much for air conditioners or lighting, because they don't do anything to fix the overvoltage, undervoltage, and dropout conditions that pose problems for these loads.  For that you need one of those voltage regulating autotransformers.

I don't have a surge protector on my TT.  Just saying.

I disagree with one part of that statement.  My surge supressor will disconnect me from the pedestal power when the voltage gets too low, and not reconnect until it senses a propper voltage.  In really killer heat I will usually start the generator and let my transfer switch take over. 
Title: Re: electrical surge protectors
Post by: banjo5491 on January 23, 2010, 03:08:06 PM
I would like to thank everyone for the information. It's greatly appreciated                     
Title: Re: electrical surge protectors
Post by: Gary RV_Wizard on January 24, 2010, 10:19:21 AM
Quote
I disagree with one part of that statement.  My surge supressor willdisconnect me from the pedestal power when the voltage gets too low...

That function is one of the major ones what distinguishes a power line monitor from a simple surge protector.  Low voltage detection and lockout is probably  a much more valuable function than just surge protection alone.
Title: Re: electrical surge protectors
Post by: taoshum on January 24, 2010, 11:17:26 AM
When we were in Mx last fall, the line voltage was usually about 132VAC.  Sometimes it would get up to 134VAC.  When the A/C was on it would drop to 128VAC.  Two questions.  One, how high is too high?  Two, which of these voltage control boxes would limit the high voltage and the low voltage and what are the ranges?  I walked around the RV park and I found one RV that was using a line conditioner that would "compensate" for low voltage but did nothing about high voltage.  Everyone else, as best I could tell either by looking or asking, did not pay any attention to the voltage. 

I don't  think we damaged anything... all of the appliances still seem to work ok but I did fret about it.

Thanks, G.
Title: Re: electrical surge protectors
Post by: John From Detroit on January 24, 2010, 11:40:19 AM
I disagree with one part of that statement.  My surge supressor will disconnect me from the pedestal power when the voltage gets too low, and not reconnect until it senses a propper voltage.  In really killer heat I will usually start the generator and let my transfer switch take over.

That is the difference between a "Surge Protector" which is really a spike supressor, (A true surge and it sounds like the 4th of july with those MOV's blowing up like firecrackers.. Trust me on that, Been there when it happened)

And a Power Line Monitor, which by the way can protect you from a surge, as well as a spike.  Not by supressing the surge (Which lasts longer than a spike) but by disconnecting same as it does with low voltage.

Or a Power Line Guardian (An even better name since "Monitor" implies a gauge, not a protection device)
Title: Re: electrical surge protectors
Post by: Jammer on January 25, 2010, 02:09:26 PM
When we were in Mx last fall, the line voltage was usually about 132VAC.  Sometimes it would get up to 134VAC.  When the A/C was on it would drop to 128VAC.  Two questions.  One, how high is too high?  Two, which of these voltage control boxes would limit the high voltage and the low voltage and what are the ranges?  I walked around the RV park and I found one RV that was using a line conditioner that would "compensate" for low voltage but did nothing about high voltage.  Everyone else, as best I could tell either by looking or asking, did not pay any attention to the voltage. 

I don't  think we damaged anything... all of the appliances still seem to work ok but I did fret about it.

Thanks, G.

The first thing to consider is that many of the voltage meters out there aren't very accurate.  I have a Camco plug-in voltage meter -- with the yellow plastic housing and the meter with the green and red zones.  I plugged it in and it reads about 8 volts higher than my digital test meter which while not of unimpeachable calibration ought to be within a volt or two.

I would expect that anywhere in 110-125 volts would be fine for any well-designed appliance.  Beyond that, it depends.

Some computers and electronics have switching power supplies that will run just fine on any voltage between 90 and 260.  The higher the voltage, the less current they draw.  Often, if these have a voltage switch for 120 and 240, it doesn't do anything but change the fuse size.

Then again, some cheap electronics have poorly regulated power supplies and might be destroyed by overvoltage.

I suspect that most of the modern converters based on switching designs are also relatively unaffected by overvoltage.  Older converters, based on linear designs, will run hotter on higher voltages.

Heating appliances, like toasters, coffee pots, space heaters, hair dryers -- will produce 21% more heat with a 10% increase in voltage.  That's enough that they may overheat.

Induction motors, like those found in A/C units, will draw somewhat less current at a higher voltage but will still run slightly hotter and be more prone to overheating.  Induction motors are most efficient (and run coolest) at their design voltage and run hotter on either higher or lower voltage.

Regarding your second question, in general, the autotransformer-based buck/boost voltage regulators, sold by Autoformer and their competition, can compensate for overvoltage the same way they compensate for undervoltage but in reverse. 
Title: Re: electrical surge protectors
Post by: Jammer on January 25, 2010, 02:19:53 PM
A true surge and it sounds like the 4th of july with those MOV's blowing up like firecrackers.. Trust me on that, Been there when it happened

They're typically spec'd at 200 volts, so it takes 144 volts RMS to trip them.  If the voltage is that high, the MOVs aren't the only thing that will blow up.

The power company guys dropped a 68,000 volt line across the 13,600 volt output of a substation near us a couple of years ago, that serves (among 200 other households) a house we rent out to some tenants.  The tenants called us up in quite a state of panic because the whole place smelled like smoke and a bunch of the circuit breakers tripped.  I went over and poked around, and called up the power company.  The conversation went kinda like, "we didn't do it, nobody saw us do it, you can't prove anything, and it will never happen again."  Right.  I think we ended up replacing some light bulbs and everything else was OK.
Title: Re: electrical surge protectors
Post by: deddy5 on January 25, 2010, 03:24:18 PM
After reading all of these posts, I am wondering, should our worries be primarily under or over voltage , in the normal hookup while camping?
I don't know what to ask for or where to obtain whatever devices are most needed for electrical hook up for a motorhome.
Title: Re: electrical surge protectors
Post by: SargeW on January 25, 2010, 03:33:24 PM
I believe that the most common problem would be an under voltage problem, however under or over can occur.  The other issue that a good surge supressor will protect you from is a miswired pedestal.  For instance when I plug into a post, I do not get immidiate power to the rig.  There are two lights that light right away, and one that blinks.  There is also a fourth that indicates a miswire situation.  By not connecting right away it gives me the chance to inspect for a miswire and disconnect if necessary. 

I bought mine from Camping World, but I am sure that they are available at many RV supply stores, both retail and on line. I am not as tech savvy as some of our posters, so I needed to buy one that was ready to go out of the box as opposed to building one.  Either way you go, I would highly recommend one for your peace of mind, and it could save you in the long run.   
Title: Re: electrical surge protectors
Post by: Jammer on January 25, 2010, 04:16:18 PM
Well, again, I don't use this stuff, I just plug in.  I do have a voltmeter and will check the voltage with it if I'm suspcious.  If it's bad enough, I can move to another spot, or another campground, or shut off the A/C and live with it, or unplug, or whatever.

In the U.S., overvoltage is rare, and undervoltage is something you might run into on hot, busy days in campgrounds that were wired to older standards or where corners were cut.

Title: Re: electrical surge protectors
Post by: afchap on January 25, 2010, 10:11:42 PM
Quote
One, how high is too high?  Two, which of these voltage control boxes would limit the high voltage and the low voltage and what are the ranges?
My digital line meter will alarm at 102v on the low side and 135v on the high side.  My TRC SurgeGuard manual says if power goes below 102v or above 132v for more than 8 seconds, it will cut incoming power. Most of the time, the SurgeGuard will cut power before the line meter gets a chance to alarm.  As I recall, the general rule is 10% over or under ... I presume 120v is the "norm".

We have found low voltage to be more common than high, but have experienced high more often than I would have expected. On several occasions we have had very high on one leg of the 50a outlet with very low on the other -- sign of a loose common somewhere on that circuit. In those cases, all I knew was that the SurgeGuard disconnected power until I checked the shore power outlet with a multi-meter. My digital line meter inside the coach is reading power from only one of the two 50a legs ... I can move it to an outlet on the other leg if I wish. The trick is to know they are on different legs (the only reason I know some in my coach is when we dealt with the aftermath of a lightning strike that melted one leg of our power cord in two!!).
Title: Re: electrical surge protectors
Post by: RVRoadTrip on January 26, 2010, 07:31:09 AM
I have a Progressive 30A Electrical Management System (EMS) and I paid about $270 for it. I installed it before going on my very first camping trip. I have never needed it and hopefully I never will, but if I ever do... it will be there to protect my camper. 
Title: Re: electrical surge protectors
Post by: taoshum on January 26, 2010, 10:37:53 AM


Regarding your second question, in general, the autotransformer-based buck/boost voltage regulators, sold by Autoformer and their competition, can compensate for overvoltage the same way they compensate for undervoltage but in reverse.

I went to their website, www.autoformers.com and I saw nothing about high voltage, except for spikes and suppressors... I probably missed something though.  thx, G.
Title: Re: electrical surge protectors
Post by: Gary RV_Wizard on January 26, 2010, 12:06:41 PM
According to the Autoformer site, it goes into Bypass at 118v, though "bypass" still results in an output that is 2% above the input voltage. Apparently there is no downward voltage adjustment in the current model.
Title: Re: electrical surge protectors
Post by: John From Detroit on January 27, 2010, 09:46:22 AM
I am told there is one company that does make one that will Buck high voltage.. There are several that make boosters.


Alas.. I forget the name of the one that does both

It is NOT Franks, and it's NOT Hughes, That I do recall
Title: Re: electrical surge protectors
Post by: afchap on January 27, 2010, 09:50:55 PM
Quote
I am told there is one company that does make one that will Buck high voltage
What do you mean by "Buck high voltage" ??  ... the TRC and Progressive surge guards (and others too no doubt) will cut off power in event of high voltage just like they will in event of low voltage. I have seen many people writhe that they use an Autoformer to aid with sagging voltage, and ALSO use a surge guard with over/under cut-off capabilities ...I presume to protect the Autoformer from high voltage?
Title: Re: electrical surge protectors
Post by: Jammer on January 27, 2010, 10:23:53 PM
Autotransformers that can boost voltage are inherently able to buck it just by reversing the connections.  If the ones on the market don't, it's because they don't have the relays or controls or whatever to do it.

A simplified way of thinking about it is that an AC voltage regulator has typically three output taps at 8, 16, and 24 volts.  It can take then 8, 16, or 24 volts and either add it to or subtract it from the input voltage.  If the controls and switches and relays only allow it to add, there's only half the potential benefit that the heavy expensive part (the transformer) can provide.

Go figure.

The ones sold for use outside the U.S., where overvoltage is more common (because they set the voltages higher to try to compensate for voltage drop and reduce the effects of undervoltage), all run both ways.
Title: Re: electrical surge protectors
Post by: taoshum on January 27, 2010, 10:58:16 PM
What do you mean by "Buck high voltage" ??  ... the TRC and Progressive surge guards (and others too no doubt) will cut off power in event of high voltage just like they will in event of low voltage. I have seen many people writhe that they use an Autoformer to aid with sagging voltage, and ALSO use a surge guard with over/under cut-off capabilities ...I presume to protect the Autoformer from high voltage?

I read about the $400 TRC surge guard and the $600 (50#) autoformer that will boost low voltage a little but I'm looking for something that will limit the high voltage to no more than 130V, not turn the power off, just limit the voltage AND limit the low voltage by boosting it where possible, not just turn off the power.  I guess it would be nice if the power goes off when the voltage gets out of range, but it would be much nicer if the power did not go off, just kept within limits.   Is this really so difficult that I have to put two of these devices in series????? and spend the better part of $1000 to do it???? Duh.
Title: Re: electrical surge protectors
Post by: Pubtym on January 28, 2010, 06:55:01 AM
I am told there is one company that does make one that will Buck high voltage.. There are several that make boosters.


Alas.. I forget the name of the one that does both

It is NOT Franks, and it's NOT Hughes, That I do recall

Powermaster..

http://antennas.startlogic.com/pm.htm

http://antennas.startlogic.com/index.html

http://www.powermasterrv.com/images/VCcomparison.pdf

Call and ask your questions to the guy at number listed..he knows Franks and used to build Hughs. I use this one...works great for me.. two years for me and no problems..

Ask for sale price..they give you a better one than posted here.

Charlie
Title: Re: electrical surge protectors
Post by: Gary RV_Wizard on January 28, 2010, 08:46:27 AM
I don't see anything on the Powermaster spec that says it bucks (reduces) overvoltage. It only talks about two levels of boost.

View the Powermaster User Manual here:
http://www.powermasterrv.com/images/VC3050UsersGuide.pdf
Title: Re: electrical surge protectors
Post by: John From Detroit on January 28, 2010, 09:31:54 AM
To Pubtym

Thanks.. Powermaster.. Yes that's it.  Thanks again

ALas, it's a bit late for me since I got a Hughes back in 2006,, but ... IF the Hughes ever needs replacement.. Powermaster it will be I think.
Title: Re: electrical surge protectors
Post by: Pubtym on January 28, 2010, 09:45:06 AM
I just got off the phone with developer of Powermaster.

Post Question 1. What will Powermaster do-not do if I plug into docking station with open ground-nuetral?

Answer: When Powermaster is first plugged in...it internally (circuitboard) does a diagnostic. That accounts for the 3-5 second delay before current outflow starts. If there is a malfunction in the dock wires..its simple to detect..Powermaster Unit MAL code is IDW (It don't work).

Post Question 2: What about high voltage?

Answer: My assumption is term "High Voltage-Overvoltage" is meant by current input to Powermaster or coach is 120V+ or minus 10V (Power Industry Standard)...ie up to 130V. With today's powerline management systems from commercial companies to user's RV park..it is extremely rare to have direct dock line voltage over 130V...that's a V give away costing the power company money.  V up to 132- 134 is not a problem for most electronics. The probability of low line voltage from dock station < 110 V is much more common bigger problem with parks having 30 amp-50 amp service and users all on line with A/Cs..electric water heaters..elect space heaters..microwave..hair dryers.. Here,...Powermaster senses the lower than 110V and begins either a stage 1 or stage 2 boost to return coach input to near or slightly above 120V.

Charlie
Title: Re: electrical surge protectors
Post by: Jammer on January 28, 2010, 11:47:41 AM
It really warms my heart to see marketing-FUD crafted with this degree of care and attention to detail, and brings back fond memories of some expert practitioners in the field who I have had the pleasure to work with over the years.

For quite some time, the NEC has required campgrounds be wired to deliver an average of  at least 33 amps for each 50 amp site, and 10 amps for each 30 amp site, with voltage drops calculated to be reasonable.  The only way it's realistic to exceed this is at older campgrounds with few 50 amp sites, where the campground is quite full and everyone is running the A/C on a hot day.

Those are the scenarios we hear about.

You can get overvoltage one of two ways, either through the power company deliberately setting the line voltage a little hot to compensate for voltage drop somewhere farther away, or because of an unbalanced load in the campground itself, which can happen if the electrician who wired the campground didn't think through which posts to wire to which leg.  Both situations are rare, in the U.S.

Then again so is low voltage, though maybe not as rare.
Title: Re: electrical surge protectors
Post by: Jammer on January 28, 2010, 11:56:24 AM
Just for interest, here is a place that sells the transformers themselves, the "active ingredient" so to speak, without any controls:

http://www.phaseconverter.com/spbtransformer.html

The KVA spec on these is the boost KVA, not the total load.  So if you have a 30 amp load and want a 12 volt boost you would need a 0.36 KVA transformer; the next size up in the chart is a .50.

These include cabinets.  There are cheaper sources that do not.

Title: Re: electrical surge protectors
Post by: Pubtym on January 28, 2010, 12:04:14 PM
Low voltage..is my #1 concern...and it is an electronics cancer to all the coach/RV electrics...seen it much more than V above 125

I use my Powermaster all the time...

Charlie
Title: Re: electrical surge protectors
Post by: taoshum on January 28, 2010, 12:13:51 PM
Low voltage..is my #1 concern...and it is an electronics cancer to all the coach/RV electrics...seen it much more than V above 125

I use my Powermaster all the time...

Charlie

The only time I've seen voltage "out of spec" is in San Carlos, Son, Mx where it was 132.  When I turned on the a/c it went down to 128.  The RV park was only 1/3 full though so I don't know what woulda happened if the place was full.
Title: Re: electrical surge protectors
Post by: Pubtym on January 28, 2010, 02:20:11 PM
My red flag for voltage issues is an older (15-20 ) year old RV park...first built to the old 20 amp infrastructure.."remodeled" by low bid electrical contractor....on a hot day (A/C required) or cold day (spot heaters in use)...MS, FL, AL, LS, TX

Look at the pedestal and outlet...has it been through the Korean War with campers? Imagine what internal connections are like?

Charlie
Title: Re: electrical surge protectors
Post by: taoshum on January 28, 2010, 02:54:33 PM
My red flag for voltage issues is an older (15-20 ) year old RV park...first built to the old 20 amp infrastructure.."remodeled" by low bid electrical contractor....on a hot day (A/C required) or cold day (spot heaters in use)...MS, FL, AL, LS, TX

Look at the pedestal and outlet...has it been through the Korean War with campers? Imagine what internal connections are like?

Charlie

I believe you... but it has been 20 years since I've been to any of those states, except S. Padre Is, TX; so I haven't been places which were that "old".  LOL, I get nervous whenever I get east of the Miss River.
Title: Re: electrical surge protectors
Post by: deanjp32 on September 30, 2017, 10:16:22 AM
I have a progressive industries EMS HW30C hardwired into my 5th wheel. The readout is showing approx 112V into the camper with only the fridge running. As soon as I turn on the furnace, coffee pot etc the voltage drops below 104V and cuts power which it should do. The parks pedestal is showing 125V yet I知 only getting 112V into the camper. Any ideas as I can only run a couple of electrical items at the same time? Should also note that I知 not using anymore than about 10 amps.
Title: Re: electrical surge protectors
Post by: garyb1st on September 30, 2017, 10:46:21 AM
Glad this thread was revitalized.  The Pace Arrow we just purchased came with a Surge Protector.   Not sure how old it is or whether it works.  Is there a way to test the unit to make sure it is working properly.  Don't recall the model, but when new, they sold for about $350.00.   
Title: Re: electrical surge protectors
Post by: Gary RV_Wizard on September 30, 2017, 11:46:15 AM
A $350 unit is probably a power monitor as well as a surge protector. The make & model would define it better.

Testing a power monitor implies feeding it various "bad" power situations to see if it responds. High/low voltage. off-frequency, miswired receptacles, etc.  I doubt if many have the capability to do that. With some basic skills and a 50A power outlet to tinker with, you could do the wiring tests, though.

The surge protection part of the device wears out over time. The MOV devices inside that do the surge handling are sacrificial. Each time a surge is absorbed, a little of its capability goes away. Bigger surges hurt more, but there are rarely frequent.
Title: Re: electrical surge protectors
Post by: garyb1st on September 30, 2017, 03:58:53 PM
A $350 unit is probably a power monitor as well as a surge protector. The make & model would define it better.

 

Thanks Gary.  Model is TRC 34750.  It is a power protector and does provide low, high and reverse polarity.  Label on the side says to plug it in and wait for 2 mins 16 secs before turning on power to RV.  It also says to refer to instruction booklet (which we don't have) if either the caution or time delay lights remain illuminated.  I guess we can just plug it in and hope it hasn't been impaired by prior surges.  Can the MOV devices be replaced?
Title: Re: electrical surge protectors
Post by: lynnmor on September 30, 2017, 04:58:09 PM
I have a progressive industries EMS HW30C hardwired into my 5th wheel. The readout is showing approx 112V into the camper with only the fridge running. As soon as I turn on the furnace, coffee pot etc the voltage drops below 104V and cuts power which it should do. The parks pedestal is showing 125V yet I知 only getting 112V into the camper. Any ideas as I can only run a couple of electrical items at the same time? Should also note that I知 not using anymore than about 10 amps.

You probably have a poor connection at the plug and it may soon burn.
Title: Re: electrical surge protectors
Post by: John From Detroit on September 30, 2017, 05:02:04 PM
In the case of the original Poster I'd guess dirty contacts on the plug. BUT another thing is measure voltage PLUGGED IN.. yes you should be able to do that on a 30 am site.. If it is a 20-30-50 use a dog bone on the 50 am outlet
Title: Re: electrical surge protectors
Post by: Kevin Means on September 30, 2017, 05:11:31 PM
I have a progressive industries EMS HW30C hardwired into my 5th wheel. The readout is showing approx 112V into the camper with only the fridge running. As soon as I turn on the furnace, coffee pot etc the voltage drops below 104V and cuts power which it should do. The parks pedestal is showing 125V yet I知 only getting 112V into the camper. Any ideas as I can only run a couple of electrical items at the same time? Should also note that I知 not using anymore than about 10 amps.
Dean, that's quite a voltage drop from just turning on a coffee maker and some low-draw appliances. I'm assuming you're reading the voltage from the HW30C's display (or a remote display?) If so, that means the voltage drop is occurring between the HW30C unit and the power pedestal. Has this been a problem at other campgrounds, or did it just start happening where you're camped now? If it just started happening, there may be a problem with the park's electrical system, or a problem in the power pedestal itself. If it's been happening at other campgrounds, you may have a problem with your power cord or plug.

The wires in the plug-head can fray, break and eventually be connected by only a few strands, which can cause the plug-head get hot when you start running heavier loads. You should also take a look at the pins sticking out of the plug head. They can become almost black with oxidation and can start to make poor contact with the socket. While cleaning them, if you notice a fluid-like oozing substance at the base of the pins (it may be dry) that's a pretty good indication that the plug-head is getting hot.

Kev



Title: Re: electrical surge protectors
Post by: Gary RV_Wizard on October 01, 2017, 11:48:13 AM
You can get the TRC 37450 user manual and troubleshooting guide at:

http://trci.net/products/surge-guard-rv/hardwires-portables/discontinued-50a-portable-wlcd-display-34750 (http://trci.net/products/surge-guard-rv/hardwires-portables/discontinued-50a-portable-wlcd-display-34750)

YOU don't have to wait 2+ minutes (actually 128 seconds) to turn on power - that delay is built into the TRC. It will wait that much time before it passes power on to the coach power cord.  Just don't be alarmed when power doesn't reach the coach right away - the delay is intentional, designed to prevent a/c compressor damage if power ever flickers on/off rapidly.

It is generally not cost effective to replace MOVs. If you have to take it to an electronics guy to do it, the labor + parts will almost surely exceed the price of a new one. If you can DIY or have a pal who can, it's a different situation.
Title: Re: electrical surge protectors
Post by: viceprice on October 01, 2017, 08:14:02 PM
We have the 30A Portable TRC Model 34830 with LCD Display.  I like the 128 sec delay and the fact it will not connect if there is a problem.  I also like the voltage and amp readout. I can calculate the total watts being used that is most helpful when on the generator and managing the stuff we use  - mostly when the A/C is running.

We also have the voltage regulator.  I feel both are cheap insurance to help protect the electronics and investment in our TT.  I saw the voltage regulator do its job with a campground low voltage at 114V. The surge protector also reported an "open ground" and a reverse polarity the first time I tried to use the generator.  Turns out I needed a "bonded plug" to use in one of the 120 V outlets on the generator. This ties the ground and common line together as it is in residential wiring.  The 30 amp outlet on the generator was wired with the line and common reversed.  I took the cover off the generator,  switched the wires on the outlet and all works fine.
Title: Re: electrical surge protectors
Post by: Gary RV_Wizard on October 02, 2017, 08:31:51 AM
Quote
I saw the voltage regulator do its job with a campground low voltage at 114V.

114v is well within the "normal" range for utility voltage. In some regions, 110v is the standard voltage the power utility provides.  Seems odd that your "voltage regulator" would activate at 114v.

Quote
The 30 amp outlet on the generator was wired with the line and common reversed.  I took the cover off the generator,  switched the wires on the outlet and all works fine.

Sad if it came from the factory or dealer that way! Maybe somebody replaced the outlet at some point and neglected to get the wiring right? Good that you found and fixed it!
Title: Re: electrical surge protectors
Post by: viceprice on October 02, 2017, 10:27:19 PM

It did come that way from the factory.  I was alerted by a customer review I had read prior to purchase that had identified the same problem.  It was the voltage regulator that provided the indication of the situation.

Just out of curiosity, how much of a problem is it with alternating current?
Title: Re: electrical surge protectors
Post by: Gary RV_Wizard on October 03, 2017, 12:28:29 PM
Many things still work OK, e.g. light bulbs and resistance heaters, but motors and digital electronics may notice the difference or not work at all. It is also potentially a safety problem.