30 amp breaker

[CHICKDOE]

no, i do not see it as an automatic problem whenever you connect a 30 amp trailer to a 50 amp pedestal using a 50 to 30 dogbone. if it is a 30 amp trailer there is still a 30 amp breaker in the trailer that is designed to trip and shut off incoming current if it exceeds 30 amps. thus the flow on the shore power cord will be limited to 30 amps. the 50 amp breaker on the pedestal will not trip. in this case being discussed here the issue, using the example cited many times above, is that neither of the two 30 amp breakers will trip if they are both seeing 25 amps nor will the 50 amp pedestal breaker. yet there is 50 amps flowing through the shore power cord and internal wiring up to the panel. if this is 30 amp wiring it could get overloaded.

[formerFR]

while CHICKDOE may be 'technically' correct... two things come to mind, at least for this particular situation from the original post:

1) 30amp coaches don't have many individual breakers. There is very little opportunity for the owner to 'overuse' it's 30amp capacity since there would only be a single roof air conditioner. The individual breakers, while technically add up to 'more' than 30amps, each circuit is not necessarily capable of using that much power. The air conditioner might be on a 20amp circuit, but it only draws maybe 8 to 10 to 12 amps while running even full bore. The Converter may be using some power, the water heater, if on 'electric' could be using some, and the outlets may be in use, but it's doubtful that more than 30amps are used for more than a few minutes(the microwave comes to mind), if ever.

2) I stopped by the RV Store today, and checked out a brand new 50amp male to 30amp female 'dog bone' adapter. It states on the 'warning/instructions' tag: "Do not use more amps thru this adapter than the RV is designed to handle. It is the responsibility of the owner to make sure that the RV usage does not exceed it's designed capability." or similar notice.
This tag simply tells the owner, up front, that the adapter is not designed to protect the owner from using it for more than the RV, or it's shore cord, is designed.

So, I can see in this situation, if you imagine that someone 'might' use 25amps 'per side', that the flow of heat/amps thru the shore cord could exceed it's designed use, and that there 'could' be a overheating of wires in the cord. I can also see, though, that the shore cord is an 'external' wiring set, not mostly contained within the RV, but mostly external between the coach and the power pedestal, giving it also less 'concern' as a weak point.

If this unit was installed with a 50amp panel, but with a 'jumped' 30amp double-pole breaker, for a potential easier 'upgrade' to a second air conditioner, a 50amp double-pole breaker, and additional individual 20amp a/c breaker later, the factory knows that the usage of an adapter to a 50amp 240v power pedestal is a possibility. I think their electrical engineers understand the possibilities, and may also understand the fact that just because a provided shore cord is for typical 30amp usage, it may also work just fine if the amperage exceeds that, in the few and rare instances where an owner might have to use an adapter to a 50amp supply, and the owner 'might' accidentally find themselves pulling slightly more than the typical design of 30amps maximum for the rv.

[5picker]

Originally Posted by Scrapper

What nobody has mentioned yet is any time you connect to a 50amp pedestal with a 50amp dogbone on a 30amp rv because of a bad 30amp outlet in the pedestal you put yourself in the same situation.

Not the same... a true 30a R/V distribution box (not the one being mentioned in this thread) has only one 30a SINGLE main breaker in it.

The R/V can never draw more than 30a before the R/V's main breaker trips.

So... to expand... yes, there will be 50a of current available to the R/V's distribution box via the shore cord but the R/V will never be able to utilize more than the 30a that is limited by the single main breaker.

There will be those that chime in and say what if... one can 'what if' anything and that is what happened in this thread.

I have never seen where the OP of this thread verified they were plugged into a pedestal using an adapter.

[CHICKDOE]

i fully agree with formfr that the possibility is remote and i agree with 5picker that we are looking for 'what ifs'. i have a 50 amp trailer and we don't worry about power management. but i have read several threads here where owners of 30 amp units need to learn a bit about power management. many of the threads start with asking why the 30 amp breaker tripped, either on the pedestal or in the trailer. the scenario usually started with something like 'i had the microwave on while brewing my coffee in the keuring and the wife turned on her hair dryer' or something to that effect. so yes the possibility is remote but it is does exist.

since i'm on my soap box (3rd cup of coffee this morning) i keep wondering about this whole issue. i have a hard time believing that this came from the factory this way. some have speculated that they ran out of 30 amp panel and used a 50 amp one. but where would they get that ganged 30 amp breaker. they would not have those is the storeroom. did they send somebody to home depot to get it? i think this was built and wired as a 50 amp trailer and it was modified and downgraded to 30 amps by a previous owner. perhaps it was one of those people that complain about how heavy a 50 amp cord is. just speculation. i do not know.

[Iwannacamp]

This is very interesting to me... I have not read it all YET, but the first concern I see other than the rigging is the size of wire they have carrying a 30A load. Is that 12 ga or less. How long is the run? To me that is the biggest safety concern so far.

[formerFR]

...this is a typical 50amp 240v panel, just like in my own coach, and in many, many 50amp motorhomes across the country.

The panel is designed to provide for incoming 50amp 240v (two hot wire, neutral, and ground) power service from most any rv park or campground.
These are typical of larger RVs and Motorhomes with two roof air conditioners, a residential fridge, electric water heater, engine block heater, etc., requiring more amps to run many of these things at once.

Because 240v power service is two hot legs, the double-pole main breaker in the Panel will 'split' these two lines - one serves the left set of breakers, and the other serves the right set of breakers. Even though panels like these can differ in setup and design, the basic routing is the same. My 50amp panel even includes a separate 30amp 'Inverter' breaker which serves the 4 15amp inverter circuit breakers thru it's 'reverse' feed from the Inverter's output. That's a mouthful, but it's just a simple way for the same main panel to provide for a 'sub panel' of breakers, powered either thru the Inverter, or thru the ShorePower/Generator.

In any case, the 'split' of the incoming power comes thru the Main Breaker, the double-pole type with a shared 'handle'... up to 50amps to one 'side', and 50amps to the other 'side' of the main panel.

With this setup, that the op provided a picture of, it occurs to me that this IS a factory supplied Main Panel, but one that is 'ready' to upgrade to a 50amp coach, IF the owner decides they want a second Roof Air Conditioner. The 'pre-wire' work has been done by the factory, only requiring the owner to then add the appropriate 20amp individual breaker for the air conditioner, replace the 30amp double-pole main breaker with a 50amp type, and replace the 30amp Shore Cord with a 50amp 4-wire type.
Sometimes these units are ordered from the factory, by the dealer, with two air conditoners, and all this work is already done. If the dealer orders it as a 30amp unit, though, the factory simply uses the same Main Panel, but with only a 30amp double-pole main breaker set, ready to be upgraded in the future.

[cavie]

Originally Posted by Scrapper

What nobody has mentioned yet is any time you connect to a 50amp pedestal with a 50amp dogbone on a 30amp rv because of a bad 30amp outlet in the pedestal you put yourself in the same situation.

Usually the dogbone is protected by the 30 amp breaker. In this case (exactly why I think dog bones should be outlawed) you can draw 25 amps on the left side and 25 amps on the right side. thus putting 50 amps on the lone wire coming from the Ped and no breaker tripping. 50 amps on a #10 wire will soon make for some interesting entertainment.

[formerFR]

that's far fetched, though, because you don't even have 60amps of breakers in a 30amp coach, so no, it's not a reality.

[JMark]

I may (probably am) too simple to understand this discussion but, surely the shore supply is connected to the panel bus - not visable in the picture as it is behind the breakers - and the electricity flows from the buss through the breaker to the line to the appliance. This is through the various black wires connected to the breakers. If this is correct then this strangly wired breaker is supplying ONE circuit within the RV and has nothing to do with any others......How could this be the main breaker?

[cavie]

Originally Posted by formerFR

...this is a typical 50amp 240v panel, just like in my own coach, and in many, many 50amp motorhomes across the country.

The panel is designed to provide for incoming 50amp 240v (two hot wire, neutral, and ground) power service from most any rv park or campground.
These are typical of larger RVs and Motorhomes with two roof air conditioners, a residential fridge, electric water heater, engine block heater, etc., requiring more amps to run many of these things at once.

Because 240v power service is two hot legs, the double-pole main breaker in the Panel will 'split' these two lines - one serves the left set of breakers, and the other serves the right set of breakers. Even though panels like these can differ in setup and design, the basic routing is the same. My 50amp panel even includes a separate 30amp 'Inverter' breaker which serves the 4 15amp inverter circuit breakers thru it's 'reverse' feed from the Inverter's output. That's a mouthful, but it's just a simple way for the same main panel to provide for a 'sub panel' of breakers, powered either thru the Inverter, or thru the ShorePower/Generator.

In any case, the 'split' of the incoming power comes thru the Main Breaker, the double-pole type with a shared 'handle'... up to 50amps to one 'side', and 50amps to the other 'side' of the main panel.

With this setup, that the op provided a picture of, it occurs to me that this IS a factory supplied Main Panel, but one that is 'ready' to upgrade to a 50amp coach, IF the owner decides they want a second Roof Air Conditioner. The 'pre-wire' work has been done by the factory, only requiring the owner to then add the appropriate 20amp individual breaker for the air conditioner, replace the 30amp double-pole main breaker with a 50amp type, and replace the 30amp Shore Cord with a 50amp 4-wire type.
Sometimes these units are ordered from the factory, by the dealer, with two air conditoners, and all this work is already done. If the dealer orders it as a 30amp unit, though, the factory simply uses the same Main Panel, but with only a 30amp double-pole main breaker set, ready to be upgraded in the future.

ART 551 of the 2014 NEC states that any RV with prewiring for A/C shall have the circuit breaker installed and the wiring attached to it. The load end shall terminate in a secured wiring box with wire nuts and a cover. The article also states the any panel having 6 or more circuits shall be a 50 amp 2 pole 240 service. 5 circuits or less shale be 30 amps 120 volts.

[5picker]

Originally Posted by JMark

I may (probably am) too simple to understand this discussion but, surely the shore supply is connected to the panel bus - not visable in the picture as it is behind the breakers - and the electricity flows from the buss through the breaker to the line to the appliance. This is through the various black wires connected to the breakers. If this is correct then this strangly wired breaker is supplying ONE circuit within the RV and has nothing to do with any others......How could this be the main breaker?

Not in this case for the MAIN breaker... the incoming current comes into the bottom of the double 30a main breaker (at the screw terminal) and is backfed to both busses (using the jumper wire) via the snap in connection of the double breaker.

The rest of the single breakers work in the conventional manner of power from the busses, through the breaker, to the load via the screw connection.

[cavie]

Originally Posted by JMark

I may (probably am) too simple to understand this discussion but, surely the shore supply is connected to the panel bus - not visable in the picture as it is behind the breakers - and the electricity flows from the buss through the breaker to the line to the appliance. This is through the various black wires connected to the breakers. If this is correct then this strangly wired breaker is supplying ONE circuit within the RV and has nothing to do with any others......How could this be the main breaker?

If you go back thew this post you will find that explanation. It is a single 120 volt wire feeding the 2 pole breaker . It is back fed. meaning the currect is flowing in reverse of normal operation. Very code compliant.

[formerFR]

Originally Posted by JMark

I may (probably am) too simple to understand this discussion but, surely the shore supply is connected to the panel bus - not visable in the picture as it is behind the breakers - and the electricity flows from the buss through the breaker to the line to the appliance. This is through the various black wires connected to the breakers. If this is correct then this strangly wired breaker is supplying ONE circuit within the RV and has nothing to do with any others......How could this be the main breaker?

50amp panels provide TWO bus bars, one for each Main Breaker, powering each ‘sides’ of breakers, just like in your home’s main panel

a 30amp panel only has one

[wmtire]

Originally Posted by monte

Why does my breaker panel have 2 30 amp breakers jumpered together? PD 4560 power center.

Originally Posted by JMark

I may (probably am) too simple to understand this discussion but, surely the shore supply is connected to the panel bus - not visable in the picture as it is behind the breakers - and the electricity flows from the buss through the breaker to the line to the appliance. This is through the various black wires connected to the breakers. If this is correct then this strangly wired breaker is supplying ONE circuit within the RV and has nothing to do with any others......How could this be the main breaker?

Jmark, the incoming shore power actually connects to the main breaker, which then the main breaker energizes the buss bar that all the other circuit breakers are connected to. This RV panel is a little different than a home panel.

Here is a link to this distribution panel the OP states he has.

https://www.progressivedyn.com/wp-co...al-English.pdf

Page 2 will show you a diagram of the incoming two hot legs from the shore power and how they connect to the MAIN circuit breakers for L1 and L2 for a normal 120/240 50 amp split phase service.

I also use this diagram below a lot when explaining 50 amp power, and it will show the same:

If you will take note of the red and black hot line in both the diagram and small inset photo in the upper left corner, you will see these ARE coming from the shore power and to the MAIN breakers. If you shut off the MAIN breakers it would cut power to the corresponding bus bars for L1 and L2....BUT the two incoming hot lines at the bottom of the main circuit breakers would still be hot.

[formerFR]

Originally Posted by cavie

If you go back thew this post you will find that explanation. It is a single 120 volt wire feeding the 2 pole breaker . It is back fed. meaning the currect is flowing in reverse of normal operation. Very code compliant.

right, my Inverter’s 30amp breaker works the same, taking the feed from the inverter and supplying it back to the special ‘sub panel’ of 15a outlet breakers via a reverse feed, which goes to their own buss bar.
RVs have little/limited room for panels, which is why several ‘custom’ designed types, like mine, are installed... it actually has THREE buss bars.

[JMark]

OK. That I understand but now I worry. let's play a little 'what if'.
What if I am doing what so many do and working on my own electrical system and I wish to change one of the 15amp breakers to a 20amp one (why is not important, we know that people do stupid things from time to time).
I look at this setup and figure out somehow that the double 30amp is the main breaker; I turn it off; I proceed to remove and change the 15amp breaker BUT I am not really carefull and I touch the screw on the 30amp breaker.....am I dead?

[wmtire]

Originally Posted by JMark

OK. That I understand but now I worry. let's play a little 'what if'.
What if I am doing what so many do and working on my own electrical system and I wish to change one of the 15amp breakers to a 20amp one (why is not important, we know that people do stupid things from time to time).
I look at this setup and figure out somehow that the double 30amp is the main breaker; I turn it off; I proceed to remove and change the 15amp breaker BUT I am not really carefull and I touch the screw on the 30amp breaker.....am I dead?

Well, I can't speak for others, but I know I would disconnect incoming shore power sources (and/or battery if also working on 12 volt) before attempting to do what you are suggesting.

If you understand MAIN breakers, then you should see the incoming wires to it and kind of know what they are....but that's just me. Even when you turn off a MAIN in a home panel, you still know (or should) not to touch the incoming hot legs to the bus.

[myredracer]

Okay, got it. The panel was originally 50 amp 120/240 volt and someone has modified it to permanently run off a 30 amp 120 volt supply. That's when there is a #10 wire connected to the 2p-30 amp breaker. What is there for a shore power cord? Detachable type (I assume)? You could look at where the shore power cord (either detachable type or not) and see how it changes to a #10 solid wire and ensure that's okay.

A 50 amp panel in an RV is exactly like a residential panel except for being 200 amps (or possibly 100). Two hot and one neutral bus. That and the fact that a residential panel doesn't use a branch circuit breaker for the main breaker and will have either incoming main lugs or a separated and dedicated main breaker.

I just can't see this being done by the factory, but based on what I've seen to date, anything is possible. A 50 amp panel would have more breaker spaces but for a 30 amp service, extra branch circuit spaces won't help much.

Some options come to mind.

1. Install a 1-pole 30 amp breaker for a main breaker and connect the incoming #10 supply wire to it. But the 2 busses need to be tied together. No main lugs to accomplish that so only way would be to use the 2p-30 breaker to do that but then you'd have two breakers in series. Not a good option.

2. Remove the panel and install a 30 amp one. Costly and time consuming.

3. Convert everything back to 50 amps and use a 50 to 30 amp pigtail adapter one the side of the RV, then a 30 amp shore power cord to the pedestal. This is a good option because there's times when you want or need to plug into a 50 amp pedestal. 50 amps will mean you can run a 2nd AC no problem (as long as voltage is good). Again, more $$ and time involved.

4. As someone mentioned above, leave everything as is except using a marrette, splice the incoming #10 to two separate #10, each feeding a terminal on the 2 pole breaker. Does it fully meet code? Maybe, maybe not. But it'd be safe, work fine electrically and besides, it's an RV and nobody will know or care. Super cheap (cost of a marrette) and easy to do (as in minutes). This is the way I'd go.

Why would anyone even think about not disconnecting the source power supply before working on anything 120 or 240 volts unless you know for 100% certain it's safe to do so or you're a professional in the field?

[bubbles]

Originally Posted by cavie

If they don't follow the NEC why do you suppose they install expensive GFI's per code. Wire panels to code. Install outlets per code spacing. Use proper GA breakers and wire. Separate grounds and neutrals per code. only 5 circuits on a 30 amp service. 6 and more requires a 50 amp service. Could go on all night Read ART#551 of the NEC. Enquiring minds want to know!

I never said Forest River didn't try to follow the guidelines laid out by the NEC. What I said is that they are not under strict compliance to adhere to the NEC install practices and are not necessarily inspected to them. The engineers, I would guess do reference the NEC for selection of material and hardware for their systems installs and on the install inspection sheets spell out the specifics to inspect to (not IAW NEC). In fact the only reference to the NEC on an electrical installation checklist for one Forest River motorhome (Isata) is for "120V/12V secure and supported according to NEC". And that, along with all the other electrical installations is signed off by a group leader. QC only checks that the documents where all inspections have been initialed and signed off by the group leaders has been completed.

[cavie]

Originally Posted by myredracer

Okay, got it. The panel was originally 50 amp 120/240 volt and someone has modified it to permanently run off a 30 amp 120 volt supply. That's when there is a #10 wire connected to the 2p-30 amp breaker. What is there for a shore power cord? Detachable type (I assume)? You could look at where the shore power cord (either detachable type or not) and see how it changes to a #10 solid wire and ensure that's okay.

A 50 amp panel in an RV is exactly like a residential panel except for being 200 amps (or possibly 100). Two hot and one neutral bus. That and the fact that a residential panel doesn't use a branch circuit breaker for the main breaker and will have either incoming main lugs or a separated and dedicated main breaker.

I just can't see this being done by the factory, but based on what I've seen to date, anything is possible. A 50 amp panel would have more breaker spaces but for a 30 amp service, extra branch circuit spaces won't help much.

Some options come to mind.

1. Install a 1-pole 30 amp breaker for a main breaker and connect the incoming #10 supply wire to it. But the 2 busses need to be tied together. No main lugs to accomplish that so only way would be to use the 2p-30 breaker to do that but then you'd have two breakers in series. Not a good option.

2. Remove the panel and install a 30 amp one. Costly and time consuming.

3. Convert everything back to 50 amps and use a 50 to 30 amp pigtail adapter one the side of the RV, then a 30 amp shore power cord to the pedestal. This is a good option because there's times when you want or need to plug into a 50 amp pedestal. 50 amps will mean you can run a 2nd AC no problem (as long as voltage is good). Again, more $$ and time involved.

4. As someone mentioned above, leave everything as is except using a marrette, splice the incoming #10 to two separate #10, each feeding a terminal on the 2 pole breaker. Does it fully meet code? Maybe, maybe not. But it'd be safe, work fine electrically and besides, it's an RV and nobody will know or care. Super cheap (cost of a marrette) and easy to do (as in minutes). This is the way I'd go.

Why would anyone even think about not disconnecting the source power supply before working on anything 120 or 240 volts unless you know for 100% certain it's safe to do so or you're a professional in the field?

There is no reason to change anything. It is perfectly safe and code compliant as long as you do not use a 50/30 dogbone.