Help! Debugging power issue

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jhughes75

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Just pulled into my next spot a few hours ago and have not been able to get stable AC from shore.  I'll list all the symptoms and what has been tested:

I did wash the trailer on the way down.  It was about 90 minutes until plugging in.  Do not see any evidence of water leaking inside near any of the electrical.  All the plugs and cords are dry.

When I first entered the trailer after connecting I thought I smelled an electrical burn smell.  The bath GFCI had tripped.

All breakers were checked and flipped several times.

I measure 116 outside on both the 20 & 30.  I cannot get my volt meter leads to give me a reading on the 50.

When on the 50A receptacle, I get varying results as to what worked and what did not.  Outlets, microwave.  Sometimes after re-plugging, different items would work or not.  When I say 'worked' for outlets, it was tested at 116v with a volt meter and a quick spin on a hand blender.  Microwave screen and bulb will fade and flicker.  GFCI makes clicking noises. 

I turned on my computer UPS and it went into backup mode even when plugged into what I thought was a good outlet.  It read 0v for input power, but at one point read 188v (yikes!).  After awhile it literally went up in smoke.

Everything works normally on the generator.

Nothing works when I step down to 30 or 20 with adapters.  I also ran 20v with an extension cord (12ga) to the neighbor.  Nothing.

I'm betting something fried, as this is a well regarded facility and the regular camp host is not familiar with any repeat electrical issues.  If so, what part do I need to hunt down on Christmas Eve?  Converter or a transfer switch?

They may have another site I can move to tomorrow.
 

Rob&Deryl

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You connected the 50a even though you could not get a reading? Yikes.

Your symptoms are a bad or missing neutral on the pedestal. Do not use till checked.

Yes, you likely fried a bunch of appliances by not fully verifying your power before connecting.
 

jhughes75

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I cannot get a reading because the volt meter leads are not long enough.  If the neutral is bad, wouldn't the surge protector block it?  It shows normal blue and green from all sources.  No appliances are fried, as I said everything works (except for the now toasted ups) when on generator.
 

Lou Schneider

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If it was a surge protector, and not a power management system, it likely also burned out.  A surge protector sacrifices itself when the voltage gets too high, while a power management system disconnects the power and will reconnect when it sees good power.

Either way, seeing extremely high voltages inside the RV while connected to 50 amp power is a classic sign of a bad neutral.  A 50 amp connection consists of two 120 volt circuits out of phase with each other so that you get 240 volts from one hot leg to the other.

The purpose of the neutral is to keep the center point between the two hot legs firmly at 0 volts, so you have 120 volts from each hot leg to the neutral.

Without the neutral, the center point is free to drift back and forth as the loads change on each side.  Unless the loads are exactly balanced, you'll have high voltage on one side of the 50 amp service and low voltage on the other, just as you're seeing.

The problem could be in the park wiring or in your power cord or plug.  I'd report the problem to the park and have them test the pedestal first.
 

John From Detroit

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There are surge protectors and surge protectors. THe HW/PT-50c (Progressive industires) and the big TRC jurge guard with the LCD display will block an open neuitral

Test  Probes leads too short to contact 50 amp outlets .... very common.

The tripped GFCI. sometimes water gets into the patio outlet and Ground Faults. In fact Suspect #1

The rest ... An open neutral will give you wildly swinging voltages on each leg but the TOTAL is alwyas 240 volt.  If you get voltages only a couple volts different between the legs. not the neutral.

Loose screws  (Many RVers have a few screws loose) in the power distribution box can explain "Works when it feels like"  did for me. one of 'em took over 3 full turns.. UNPLUG and use flashlight to check.
 

samthetramp

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I went thru this the very first time I plugged in my brand new 5ver. Talk about disappointment. I bought a plug in inline surge protector/electrical tester immediately. Fried my fire place and vac system. Used 3 different volt meters and all said I had 120/240 at the shore power. Listen to the previous posts.
 

Bobtop46

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The fact that everything works on the generator proves that it is the post or shore power cable.  Sort of proves that the ATS is working also.  That only leaves the post, cable, or surge protector.  The smell you had could have been the surge protector, but if it was surge protector then you would be getting no power inside the coach to have high/no power issues.  Surge protectors fry or cut power either way no power after that.  That only leaves two things left.  Shore power cord or the post.  The campground should check the post for loose or fried wires.  You should do a close examination of your cord and plug.  Loose, frayed, burnt, damaged, or water intrusion.  Not sure if you have the kind of cord that plugs in at both ends, a male and a female end check it.
 

Gary RV_Wizard

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Agree that the symptoms using the 50A outlet are that of a weak or open neutral.  The voltage on a 50A supply with a bad neutral will vary with the load in each of the two hot legs and can easily run over 160v on one while the other is proportionally below 120v. Voltage will also change as amp loads on each leg go up or down.

Does your RV have a 50A shore cord, or 30A?  And what brand/model of "surge protector" do you have? As others stated, some just do "surge", some make a one time outlet check,  and others have continuous high/low voltage protection as well. 
 

cavie

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jhughes75 said:
I cannot get a reading because the volt meter leads are not long enough.  If the neutral is bad, wouldn't the surge protector block it?  It shows normal blue and green from all sources.  No appliances are fried, as I said everything works (except for the now toasted ups) when on generator.

Not if all you have is a surge protector and not and EMS A surge protector blocks nothing but high voltages surges.
 

John From Detroit

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Ok TRC (Technical Research Corp) Calles their power protector a SURGE GUARD. but read on this term is misused big time. The expensive TRC units are in fact surge guards. But...

Progressive Industires calls theres an Enegry Monitoring System.  (NOt to be confused with Intelletec's Energy MANAGEMENT system different ball game).

What these do
They monitor voltage and frequencuy also amps They check for open neutral, Open ground INverse polarity (Normally only on 30 amp. this is where the park swaps the hot and neutral wires on the outlet) and other problems

IF they see a problem they DO NOT CONNECT the RV unless you override.

Voltage. If it goes too high (Surge) They will shut you off to protect you
If it goes too low (Brown out) Same thing

Frequency.. Some can do that too again too high/low

THen when things return to normal they count down anywhere from 14 seconds to about 3 minutes and THEN connect... 

Finally if there is a SPIKE (A very brief high voltage, often caused by say an air conditioner shutting of) THey CLIP that (Metal Oxide Varistors are the magic discs).

MOV's are cheap and are often tossed into other devices. Like a Hughes autoformer or even an automatic transfer switch. I have some behind my breaker panel.  Just more protection against the most common problem..

ONe thing all the devices above share is an information display. NOT JUST LED's. on hard wired unit it will be a remote display on a portable there is a display on the box.. It will show the voltage and the amperage on each leg 50 amps (or total 30 amps) and if it shuts you down the reason.

Next we get "Surge Guards" (note the quotes) these are spike supression only they do not protect you against say plugging into a 240 volt outlet. THEY may have LED's to indicater "OPEN GROUND" or Reverse polarity (or not) but they do nothign to protect you other than indicate the issue.

The six outlet "Surge Surressor" strips you plug a computer in... That's what they are.

NO LCD or LED display with error codes. Just a few LED's if that.

That delay I promised you more on.

WHen I was in GA BANG... No power .. An inattentive driver missed the curve in front of the campground.    WHat he did now miss was the power pole with the transformer that fed the park  He took out quite a bit of houses in addition to the park. also knocked out telephone nad internet services.

Well when power was restored everybody and their neighbor the A/C tried to kick in (This is GA after all) and other stuff as well.  Terrible max load situtation. the voltage drops. then the A/C's give up cause not enough to kick-start 'em and try again. and the rollar coaster starts voltage wise.

All this time my unit is going 180-179-178-176-185-174 ......
By the time it got down to 5-4-3-2-1-CLUNK the rollar coaster had pulled into station and voltage was stable.

NICE.
 

jhughes75

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Updates and answers:

I have a Progressive Industries SSP-50XL Portable 50 Amp RV Smart Surge Protector W/Weather Shield.  The outside outlets were dry.

I replaced the main 50A cord the next morning.  Have not validated whether or not the previous one was actually a problem.  All my outlets and elec water heater have been fine for about 30 hours now.  The clicking was not actually the GFCI but my razor charger. 

I used the microwave after all this started when on the generator for a few minutes, but it now appears to be dead.  The outlet tests good and I ran the micro to another circuit and nothing.  Will be replacing tomorrow hopefully.  It also does not come on when I went generator again.

The only remaining item is that I believe my AC to 12V DC converter also went.  My batteries are not keeping full when on shore power, and when I shut off at the batteries I lose all 12V lights which I'm pretty sure is not correct behavior.  At one point, the converter breaker was tripped.  Would it have its own reset, breaker, or fuse?  I need to locate it.
 

John From Detroit

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Earlier I mentioned that there are "Surge Guards" and SURGE GUARDS.

The Progressive Industries SSP-50XL Portable 50 Amp RV Smart Surge Protector  is the former. Protection against SPIKES but no protection against sustained high/low voltages  If you plug into a 240 volt 30 amp outlet using and adapter. It will not do much for you save perhaps fail.

IT will tell about park wiring problems but that is about all.

Check out the PT-50-c
 

cavie

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jhughes75 said:
Updates and answers:

I have a Progressive Industries SSP-50XL Portable 50 Amp RV Smart Surge Protector W/Weather Shield.  The outside outlets were dry.

I replaced the main 50A cord the next morning.  Have not validated whether or not the previous one was actually a problem.  All my outlets and elec water heater have been fine for about 30 hours now.  The clicking was not actually the GFCI but my razor charger. 

I used the microwave after all this started when on the generator for a few minutes, but it now appears to be dead.  The outlet tests good and I ran the micro to another circuit and nothing.  Will be replacing tomorrow hopefully.  It also does not come on when I went generator again.

The only remaining item is that I believe my AC to 12V DC converter also went.  My batteries are not keeping full when on shore power, and when I shut off at the batteries I lose all 12V lights which I'm pretty sure is not correct behavior.  At one point, the converter breaker was tripped.  Would it have its own reset, breaker, or fuse?  I need to locate it.


You need to call an electrician. Your surge protector is probably toasted. How do you know a breaker is tripped if you don't know where it is? Yes the converter is on a breaker. It also has fuses protecting the battery. Stop plalying electrician and call one.
 

Gary RV_Wizard

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Chances are the microwave just blew its internal fuse - nearly all microwaves have one inside.  Finding someone who would take the time and effort to get at it and replace the fuse if likely to be challenging, though.  It's usually either a DIY job or finding a handyman-type willing to struggle through it.  However, replacing a microwave is often the same challenge, especially if the exact same model of microwave is no longer available (a common situation).
 

jhughes75

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DIY car wash with power sprayers and foam brush.  The thing was filthy and was heading to a place with age and condition rules.  I had not been able to clean it in 4 months due to weather and schedule.

I'll be removing the microwave shortly and will check the fuse before taking measurements and going to Home Depot.

I will check out the more thorough power management system for the future, thanks.  When you say the surge protector is 'toasted' what would be the symptoms?  It is currently lighted up, in use, with the new cord.

I have done full wiring in houses, and fixed more mistakes by 'electricians' than I can begin to list here.  None were going to come out on Christmas Eve/Day except for a pretty penny. 

Sorry, when I said "locate it" I meant the AC/DC converter box for testing and replacement, not the breaker box.
 

jhughes75

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Fuses in both the microwave (250V 20A, interesting but I guess this is standard) and the Iota converter are good.  No output from the converter, I assume I should get a DC reading even with no draw.  Have replacements for both ordered.
 

Rob&Deryl

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Note that MOVs tend to be one shots. They protect against a high voltage spike by sacrificing themselves. They are found in almost all plastic power strips. After one use, they do nothing useful but may contribute to tripped GFIs because sometimes when they sacrifice themselves, they don?t open all the way but end up leaking the power lead to ground. Horrible little beasts.
 

samthetramp

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This is what I'm using currently.

https://rvpower.southwire.com/products/surge-protection/50a-entry-level-portable-surge-protector-model-44270/
 

Gary RV_Wizard

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Sam, your Surge Guard 44270 unit is similar to jhighes75's Progressive 50XL.  It  tests the power outlet when you plug in but does not monitor for subsequent voltage changes of faults.  It will detect an open neutral when you plug in, but if the neutral is poor quality rather than totally missing, it won't recognize that, nor will it detect the subsequent high/low voltage that is the result.  It is good protection, but not 100%.
 
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