50A Surge protector 30A camper

[Nomadicchefs]

We have some newbie neighbors with a dilemma I thought I might be able to help them with, via your advice from here. They have a 50amp surge protector and a 30amp camper. I guess the 50 was all that particular rv store had at the time and as they were traveling, didn't want to have one shipped somewhere. The guys there told them they could use a dogbone adapter from the surge protector to reduce it down to 30amp and plug their camper into that. I assume this would be fine, but it seems other threads are stating not, am I missing something? Wouldn't it be the same as having no protector at all and simply plugging into a dogbone? Since we have our main box in the camper in case a breaker trips? What can I tell them? Thanks all!!

[notanlines]

I do see a problem as far as being protected. I also see a problem down the road when they camp with 30 amp 'only' service. They would plug in a 30 to 50 dog bone, then the surge protector, then a regular 50 to 30 dog bone and then the RV. A little too convoluted, but, as the old punch-line goes, "It's not my dog."

[Nomadicchefs]

I don't see a problem as far as being protected. I see a problem down the road when they camp with 30 amp 'only' service. They would plug in a 30 to 50 dog bone, then the surge protector, then a regular 50 to 30 dog bone and then the RV. A little too convoluted, but, as the old punch-line goes, "It's not my dog."
Yea, I was thinking it seems like a little bit excessive in the adapter department, but I know the protector was expensive because we have the same one for our camper. So I hated to let them down if it's not going to work.

[jsb5717]

It's a legitimate concern. The answer really lies with the particular surge protector. Different manufacturers will have different answers on that issue. I saw a video on etrailer that stated that you cannot step down the one they sell...I believe it's a Camco one.

However, I contacted Progressive Industries regarding their protectors and they said you could step them down with a dogbone adapter.

Best to check to whoever made the one they've got.

[jsb5717]

I don't see a problem as far as being protected. I see a problem down the road when they camp with 30 amp 'only' service. They would plug in a 30 to 50 dog bone, then the surge protector, then a regular 50 to 30 dog bone and then the RV. A little too convoluted, but, as the old punch-line goes, "It's not my dog."

In theory you could use an adapter to plug the 50 amp protector into the 30 amp service, then use another adapter to plug the 30 amp trailer into the 50 amp protector.

I assume the adapters all follow a standardized system for which wire to drop in the step up/step down process. The Surge Protector should indicate whether the above contraption still provides adequate power to the coach.

In the end, if the protector is suitable for step down use, it's still protecting against a serious surge up to its rating.

[Nomadicchefs]

The pedestal here is only 50amp, so they are just putting the 50 to 30 adapter at the end of the surge protector. They have the progressive industries EMS-PT50X, and progressive told them not to use any adapters as it would cause an electrical fire. What I don't understand is how it's any different than using a 50 to 30 adapter right at the pedestal if you didn't have a surge protector? You're still dropping down no matter what there's still only 1 leg and 30 amps going to the camper, correct? Now they've got me super interested in this predicament.

[NH_Bulldog]

Think of it this way: If you have wiring in your house that will support a 15a load (14ga), and you connect that to a 20a breaker (intended for 12 ga wire), what will happen if you overload that 15a wiring? The breaker won't trip before the wires melt and will start a fire. In this case, unless you have a 30a breaker/surge protector, the wiring in the camper will be toast before it trips that 50a breaker/surge protector. Kind of defeats the purpose of a surge protector doesn't it?

[jsb5717]

the difference may be in the model. Mine is the SPP-50X. I'm sure the issue is not in the adapters but in the electronics of the surge protector. A current mis-match can certainly cause a problem. I would definately operate on the advise of the manufacturer.

Sounds like your friend should be able to return the SP he bought since it can't perform as promised by the dealer.

[linux3]

P=IE. Power = Volts times Amps.
We are dealing with 120 Volts.
The surge protector, in theory, kicks in when the power exceeds 6KW more or less.
The TT in question is built and wired for a max of 3.6KW. Do you see the problem here?
Switching from a 30 AMP plug to a 50 AMP adapter into a surge protector and then switching back to 30 AMP to plug into the TT.
I do not want to be parked next to them.
Further, shame, shame on the RV store that sold them that device.

[Nomadicchefs]

I'll let them know, thanks.

[John&Genny]

Some of you are comparing apples to oranges. A surge arrestor, or in this case a Electrical Management System is quite different than electrical breakers or fuses. A EMS monitors the line voltage looking for sags (brownouts) or overvoltage conditions. If it detects something that might be a problem, it will disconnect the power going to the TT. It also checks for improper wiring (disconnected grounds, reversed hot/neutral, etc.) and will not even apply power to the TT unless everything checks out OK. The Progressive 50A EMS is being plugged into a 50A connector at the pedestal, so no problem there. And I fail to see what the problem would be if they used a 50A to 30A dogbone going from the EMS to the TT. It would not be any different if they were plugging the dogbone into the pedestal directly. Certainly the 50A Progressive would handle any current or power requirements that a 30A TT would require.

Having said that, it would still probably be best if they took back the 50A and got a 30A Progressive instead. Not all sites have 50A service, but almost all sites have 30A. Also, it’s better in the long run not to have too many electrical adapters in the chain if you can avoid it.

[Logan X]

Some of you are comparing apples to oranges. A surge arrestor, or in this case a Electrical Management System is quite different than electrical breakers or fuses. A EMS monitors the line voltage looking for sags (brownouts) or overvoltage conditions. If it detects something that might be a problem, it will disconnect the power going to the TT. It also checks for improper wiring (disconnected grounds, reversed hot/neutral, etc.) and will not even apply power to the TT unless everything checks out OK. The Progressive 50A EMS is being plugged into a 50A connector at the pedestal, so no problem there. And I fail to see what the problem would be if they used a 50A to 30A dogbone going from the EMS to the TT. It would not be any different if they were plugging the dogbone into the pedestal directly. Certainly the 50A Progressive would handle any current or power requirements that a 30A TT would require.

Having said that, it would still probably be best if they took back the 50A and got a 30A Progressive instead. Not all sites have 50A service, but almost all sites have 30A. Also, it’s better in the long run not to have too many electrical adapters in the chain if you can avoid it.

Unless I’m mistaken, the EMS device has overload and surge protection in addition to the other functions it provides. If the EMS provides overload protection at 50 amps, considerable overload damage could occur to a 30 amp electrical system before the 50 amp protection would kick in. I’m no expert but that seems logical to me.

[JRTJH]

If the last couple of posts are correct, then anyone (ALL OF US) with 30 amp EMS and ALL OF US with 50 amp EMS systems who have a 15 amp circuit breaker on an "outlet line" in our trailer, have a 20 amp breaker for the air conditioner or have a 15 amp GFI circuit in our trailer wouldn't have protection "INSIDE" our units, only the 6KW or 3.6KW part would be protected.

In actuality, if there is a "surge" it will typically be a lightening strike or a "massive voltage" (well over 1000 volts) and the EMS (whether a dual line 50 amp device or a single line 30 amp device) would shut down power. If there is over the voltage limit or under the voltage limit (typically they monitor for voltage from 105-130 VAC) then the system will shut down. It doesn't matter if it's line 1 or on line 2, the entire system will shut down. There is no need for circuit protection (at the source/power pole) if there is protection at the circuit level. Think about your home circuit breaker panel. Typically they have a 200 amp "main breaker" and several other breakers ranging from 50 amp/220 for stoves and furnaces, 30 amp/220 for dryers/AC systems, 20 amp/110 for general circuits and some 15 amp/110 for GFI or light duty general circuits. If there's a problem with one line of the 50 amp/220 circuit, there is no "dangerous condition" on any of the "lower amp breaker systems, it doesn't matter whether they are on line 1 or line 2 from the "main breaker".

I'd say that if the 50 amp EMS is connected to a 30 amp power source, it is going to monitor the "LINE IN" for 105-130 VAC/60Hz/50 amps/0 errors. There will be no input on the other line, so the EMS would need to be placed in BYPASS to power the second 30 amp adapter. From that point on, it's the same as plugging the trailer into any power source. The trailer power panel 30 amp breaker will protect the trailer circuits, the power cord (up to the EMS) and the 30 amp (power pole plug) will be protected by a circuit breaker further upstream, probably in the house breaker panel.

I don't see any issue with using the 50 amp EMS on a 30 amp trailer. It will provide the same "surge/lightening" protection no matter how much amperage is being used in the trailer and none of the EMS systems I've ever seen have a "circuit breaker protection built in" so it's irrelevant whether it's monitoring 50 amps or 30 amps, all it does is give a LED reading of how much is being consumed. ALL of the circuit breaker protection is provided by the power center INSIDE the trailer, not the EMS.

The "rub" as I see it, is that SOME EMS systems, when in bypass, will not monitor for low voltage conditions, the manufacturer for that type (CAMCO) recommends not using a 30/50/30 multiple adapter setup. The other brand, Progressive, monitors for low voltage while in bypass, so that brand will work with a multiple adapter setup.

[linux3]

The trailer power panel 30 amp breaker will protect the trailer circuits, the power cord (up to the EMS) and the 30 amp (power pole plug) will be protected by a circuit breaker further upstream, probably in the house breaker panel..
OK, I'm an EE, retired.
Circuit breakers will trip just in time to protect themselves and burn out anything down stream.
If all you needed is the circuit breakers then why buy a surge protector?
In a proper electrical circuit everything must be sized and rated as required.
The surge protector is there to guard against Brown Outs, high voltage and spikes. Spikes, you know, what you get in a poorly designed campground when someone or a bunch of someones connect or disconnect.

Look, size devices for need not wishes.
But then RV salesman say my Silverado can pull a 32" camper.

[jsb5717]

I know virtually nothing about the technical aspects of this topic. I yield to those who do.

I do know that others on other threads have commented about damaged components in their rigs due to spikes and/or inconsistent voltage in parks. I'd rather have some cheap insurance and never need it than wish I had it when it's too late.

[JRTJH]

OK, I'm an EE, retired.
Circuit breakers will trip just in time to protect themselves and burn out anything down stream.
If all you needed is the circuit breakers then why buy a surge protector?
In a proper electrical circuit everything must be sized and rated as required.
The surge protector is there to guard against Brown Outs, high voltage and spikes. Spikes, you know, what you get in a poorly designed campground when someone or a bunch of someones connect or disconnect.

Look, size devices for need not wishes.
But then RV salesman say my Silverado can pull a 32" camper.

I never said, "All you need is circuit breakers"... I did say that the EMS doesn't protect against amperage overload.....

There is NO amperage protection (only visual monitoring and display) of the amperage load. If you exceed the amperage, it's the circuit breaker, NOT the EMS, that trips to protect the circuitry. So, whether it's a 100 amp, a 50 amp or a 30 amp EMS, it does, as you say, protect against brownouts, surges, spikes, ground issues, hot neutrals, but it does NOT protect against amperage consumption. That's entirely left up to the power panel in the trailer (for trailer distribution) and to the campground circuit breaker for "upstream protection".

[Snoking]

Biggest issue is plugging the device into a 50amp out outlet with a 30 trailer, as the shore cable and wiring from the trailers inlet to the trailer electrical panel is not protected correctly. We routinely plug in our 50amp TT with and 30 to 50 amp adapter. Just a few minutes ago DW started the microwave while the WH and portable heater were running and we are on a 30AMP outlet. The hardwired PI unit dumped the power based on low voltage.

I see no problem running an adapter on each side of the portable PI unit. The PI unit will still do it's job of looking for open grounds or neutrals, reverse polarity , low or over voltage, freguency etc.

PI units do not error or trip on amperage, that is left to the circuit breakers.

[Logan X]

I never said, "All you need is circuit breakers"... I did say that the EMS doesn't protect against amperage overload.....

There is NO amperage protection (only visual monitoring and display) of the amperage load. If you exceed the amperage, it's the circuit breaker, NOT the EMS, that trips to protect the circuitry. So, whether it's a 100 amp, a 50 amp or a 30 amp EMS, it does, as you say, protect against brownouts, surges, spikes, ground issues, hot neutrals, but it does NOT protect against amperage consumption. That's entirely left up to the power panel in the trailer (for trailer distribution) and to the campground circuit breaker for "upstream protection".

So if I’m understanding correctly, the trailer’s circuit breakers will protect the trailer from an amperage overload, the EMS will protect from a voltage overload (and all of the other above mentioned problems). That makes sense.

[xrated]

Here is a list of things the P.I. EMS does/protects...


Product Features:

Over/Under Voltage Protection

Open Ground, Open Neutral & Reverse Polarity Detection

Accidental 240V Protection

Miswired Pedestal Indication

Surge Failure Indicator

Amperage Meter Display

Previous Error Code

A/C Frequency Protection

Time Delay (136 seconds)

Adjustable Time Delay

Thermally Protected

Built-in Scrolling Digital Display

Field Serviceable

UL Certified and Canadian Approved

Lifetime Warranty

[DocP]

I have 2 of the 50 amp Hughes autoformers (both surge protector and voltage booster) - one for my 50 amp Cougar, and the other for my 30 amp camper. I went with the 50 amp model for my 30 amp camper based on the following information taken directly from the Hughes owner's manual:

"Match the Autoformer rating to your RV: If your RV has a 4-wire power cord, you should use a 50-amp Autoformer. If your RV has a 3-wire power cord, use a 30-amp Autoformer. Always use the highest amperage power source available. You can convert to a lower amperage outlet by using appropriate adaptors, for example: a 50-amp Autoformer can run on a 30 or 20-amp power source. Of course, you will be restricted to that lower amperage, but the Autoformer will boost the voltage when necessary. Be careful not to overload the lower amperage park power box."

My thinking was that if (when) I sell the 30 amp camper, I won't have to buy another unit if I upgrade to another 50 amp camper.

[JRTJH]

So if I’m understanding correctly, the trailer’s circuit breakers will protect the trailer from an amperage overload, the EMS will protect from a voltage overload (and all of the other above mentioned problems). That makes sense.

You are correct. Plus, all the things that x-rated (Vern) listed are conditions and features of MOST EMS units. They all do "about the same thing" and now, Surge-Guard and PI offer "lifetime warranty" on their units, so they are "more alike than ever before".....

[JRTJH]

Biggest issue is plugging the device into a 50amp out outlet with a 30 trailer, as the shore cable and wiring from the trailers inlet to the trailer electrical panel is not protected correctly. We routinely plug in our 50amp TT with and 30 to 50 amp adapter. Just a few minutes ago DW started the microwave while the WH and portable heater were running and we are on a 30AMP outlet. The hardwired PI unit dumped the power based on low voltage.

I see no problem running an adapter on each side of the portable PI unit. The PI unit will still do it's job of looking for open grounds or neutrals, reverse polarity , low or over voltage, freguency etc.

PI units do not error or trip on amperage, that is left to the circuit breakers.

When you consider that the 25' 30 amp shore power cord is "rated 30 amps" at 50 feet, a 25' length of cord (the length most of us have) will carry somewhere between 34-40 amps for a short time without damage. The 30 amp power center in the trailer is "protected by a 30 amp circuit breaker. Theoretically (I haven't held the wire ends to verify this) if you plug the 30 amp shore power cord into a 50 amp outlet on the campground power pole, once you turn on enough "stuff" in the trailer to draw 30 amps, everything will work as designed. If you overload anything in the trailer and begin drawing 31 amps, the TRAILER main circuit breaker will trip, shutting down all power into the trailer (instantly eliminating ALL potential for overload. Since the shore power cord is rated at 30 amps at 50' long, it will carry more than that since it's only 25' long. Essentially, there's no way to damage the shore power cord or to overload it while attached to the trailer (as long as the trailer 30 amp breaker is functional)...

Of course, if you run over the shore power cord with a lawn mower, intentionally connect it to something drawing 50 amps (without circuit breaker protection) or somehow damage it, then all bets are off. However those are NOT "normal use" of the shore power cord, any adapter and the trailer main power center.

The rest of your post is "spot on" and as you said, the EMS will work as designed without problems.

[Snoking]

Circuit breakers are there for more than a single reason, along with electrical codes. Yes the 30 Amp main breaker in the power center will protect from overloads within the unit down stream of the panel. It will not protect one from a problem up stream of the power center that is supplied with wiring rated for 30amps and is feed from a 50amp supply.

In life beyound RVs this would be a code violation. Example would be a sub panel in your garage wired with #10 wire from a 50amp breaker in main panel. Red tag, failed inspection.

People just need to be aware of the risk no matter how small, as their lives could depend on it. Example could be a loose connection on a lead comimg in to the trailer at the inlet or panel that created enough heat to melt to insulation on the wires and allow a short to occur.

[trmanning]

Anytime you use a protector over the amperage it’s protecting you run the risk of damage to the appliances. Then you have the chance of serious damage. A 30 amp surge protector protects up to 30 amps. Should you put a 15 amp fuse in a 10 amp circuit? I would never do so! Just hate to see it destroy their dreams.

[LHaven]

Think of it this way: If you have wiring in your house that will support a 15a load (14ga), and you connect that to a 20a breaker (intended for 12 ga wire), what will happen if you overload that 15a wiring? The breaker won't trip before the wires melt and will start a fire. In this case, unless you have a 30a breaker/surge protector, the wiring in the camper will be toast before it trips that 50a breaker/surge protector. Kind of defeats the purpose of a surge protector doesn't it?

A surge protector isn't a fuse or circuit breaker. Fuses and circuit breakers protect against over-current. Surge protectors protect against over-voltage. Whether you use a 30A or a 50A outlet, the voltage is still 120V between hot and neutral. An RV with a 30A adapter will be using only one of those legs. As long as the surge protector protects each of the legs independently, there's no reason you can't use it to protect a 30A RV.

(Though I do agree this is an awkward unit to manage when you're camping at a park with only 30A outlets.)

[LHaven]

if you plug the 30 amp shore power cord into a 50 amp outlet on the campground power pole, once you turn on enough "stuff" in the trailer to draw 30 amps, everything will work as designed.

Absolutely. 40 years ago, I had a power engineer explain it to me this way, and I've remembered this analogy ever since to keep my head straight on this issue:

The average lamp in your home has 14ga wire, which is rated only for 15A. You routinely plug them into house outlets that are rated and fused to supply 20A. This is NOT a violation of code or good practice, because the lamp is never going to draw more than some fraction of 15A. Yes, there is a fire danger if some adverse event physically shorts the lamp cord, but that's not considered a normal event. (Especially since it would have to be shorted in such a manner as to consume more than 15A but less than 20A, which is highly improbable.)

[vmyoung61]

Correct me if I'm wrong. Doesn't the 50 to 30 adapter just run the RV off one leg of the 50 service? So ... If you overload one leg, won't it trip? Besides - the Progressive is more than surge protection. You plug it in to make sure the pedistal is safe for the rv. It would still protect the 30 amp RV from bad wiring by showing an error.

[bobbecky]

Most people, including most electricians, believe breakers and fuses protect connected loads. That is not the case. Breakers and fuses protect the system from a fault in the connected circuit, so the rest of the system doesn't fail due to an issue on the single circuit. Then, the main breaker in the RV panel does not protect the RV, but protects the main feed from a fault in the panel that exceeds whatever the main breaker is rated at. This continues all the way up stream, even to the utility sub station, with fuses and breakers protecting the source from failures and faults on the load sides. Yes, the fuse or breaker will open when a load exceeds the amp rating, but that is a potential fault that the device is protecting the rest of the system from.

If you have an RV with a 30 amp panel plugged into a 50 amp receptacle in a pedestal, the 30 amp breaker in the RV will open if the load or a fault occurs, to protect the source side of the RV panel. If the 30 amp shore cord fails due to a cut or some other damage, the 50 amp pedestal breaker will open up to protect the rest of the RV park from the shore cord failure. If something happens inside the pedestal, the breaker that feeds the string of pedestals inside the park's main panel will open up to protect the rest of the park, and so on up stream.

[jimborokz]

Some of you are comparing apples to oranges. A surge arrestor, or in this case a Electrical Management System is quite different than electrical breakers or fuses. A EMS monitors the line voltage looking for sags (brownouts) or overvoltage conditions. If it detects something that might be a problem, it will disconnect the power going to the TT. It also checks for improper wiring (disconnected grounds, reversed hot/neutral, etc.) and will not even apply power to the TT unless everything checks out OK. The Progressive 50A EMS is being plugged into a 50A connector at the pedestal, so no problem there. And I fail to see what the problem would be if they used a 50A to 30A dogbone going from the EMS to the TT. It would not be any different if they were plugging the dogbone into the pedestal directly. Certainly the 50A Progressive would handle any current or power requirements that a 30A TT would require.

Having said that, it would still probably be best if they took back the 50A and got a 30A Progressive instead. Not all sites have 50A service, but almost all sites have 30A. Also, it’s better in the long run not to have too many electrical adapters in the chain if you can avoid it.

I believe this is spot on. Basically the EMS is monitoring the post which in this case is 50A. The idea that you could overload the 30A camper and not trip the 50A breaker at the post has nothing to do with the EMS. You would still not trip that breaker even without the EMS. You should at that point be tripping the 30A main in the camper.

[gearhead]

I run a portable Progressive 50 amp on my 30 amp Bigfoot all the time. Just use a dogbone between the camper wire and the Progressive. I have a 30 to 50 dogbone for 30 only pedestals but don't recall if I ever used it.
I have a 30amp SurgeGuard but don't trust it.

[kksfish]

For all the reasons John and Vern mention........The 50 Amp surge protector and assorted dog ones are what I have used for years and will continue to use! With the 50 I am protected in just about any configuration imaginable!
I have attended a number of seminars conducted by the major manufacturers of over current devices and I instructed 4th year apprenticeship programs and as such have experimented with many OC/grounding scenarios and I am very comfortable with this.....