Electrical C Honnections

[oldjohnt]

 

 

 

2 hours ago, Kirk Wood said:

The reason they are made is that they work very well and can be safely used. Even John admits to having used one. And they get U/L approval because they pass reasonable safety testing

Sure a 6 inch piece of rubber cord can be UL approved, it can be seen on sections of wire,,,,,,,,,,,,Sure a Receptacle can be UL approved,,,,,,,,,,,,,,Sure a male Plug can be UL approved,,,,,,,,,,Sure the risk is low,,,,,,,,,,,,Sure it may never cause a problem,,,,,,,,,,Sure I used my 50 30 dogbone one time............

HOWEVER THE FACT AND BOTTOM LINE REMAINS using only 30 amp rated wire between the RV Power Pedestal and the RV panel WHICH HAS A 50 AMP BREAKER designed to protect wire rated for 50 NOT 30 Amps IS UNSAFE (even if low) AND A VIOLATION OF THE VERY ESSENCE OF THE NEC'S OVER CURRENT PROTECTION                     PERIOD.............

Ever wonder about a 30 amp RV using 30 amp rated wire overcurrent protected by a 30    NOT    50 amp breaker ???? Its because that wire is protected by the 30 amp breaker in the pedestal SO IT CANT DRAW MORE CURRENT THEN THE INSULATION CAN WITHSTAND without it degrading or melting and exposing it to a short or water or the RV.

Ever wonder why a 50 amp breaker in a 50 amp pedestal uses a 50 NOTTTTTTTT a 30 amp cord  hmmmmmmmmmmm. Heres a clue, because 50 amp wire can withstand 50 amps BEFORE the insulation can fail, BUT 30 AMP WIRE WOULD OVERHEAT 

LISTEN GUYS ITS NOT ROCKET SCIENCE to realize to protect wire rated at 30 amps you use a 30 amp breaker NOTTTTTTTTT a 50 so there cant be so much current flow to melt or degrade the insulation. Look in any electrical installation and you will see say a 20 amp breaker when 20 amp wire is used,,,,,,,,,,,, and a 30 when 30 amp wire is used,,,,,,,,,,, and 50 etc etc.  YOU WILL NEVER SEE A 50 AMP BREAKER WHEN THE FEEDER WIRE FROM THE PANEL IS ONLYYYYYYYYYY 30 AMP RATED. What you will see is a 30 amp breaker when 30 amp wire is used hmmmmmmmmm that may just tell you something

I give up lol I have tried and tried my level best (but failed miserably grrrrrrrrrr my bad) to educate everyone here, sparkies and non sparkies alike, and to explain the risks involved and the essence of how the NEC deals with overcurrent protection so you cant get enough current to melt or degrade the insulation AND USING 30 AMP WIRE THAT CAN PASS 50 AMPS IS UNSAFE AND A RISK (albeit low) and if you cant grasp that very basic concept you're simply neverrrrrrrrrrrr gonna get it. BUT THAT DONT MEAN YOURE A BAD PERSON. There are plumbers and carpenters and doctors  and teachers and farmers who just cant know what professional electricians and technicians and engineers know so DONT FEEL BAD ANYONE if you don't get it..............I "get it" because I spent much of my career getting educated in then practicing electrical power distribution with the NEC by my side as my daily Bible and having attended numerous NEC seminars which is why I DO UNDERSTAND OVERCURRENT PROTECTION AND WHY YOU PROTECT 30  AMP WIRE WITH A 30 NOTTTTTTTTTTTT A 50 AMP BREAKER...........and that remains so even if a lay person cant understand why TOLD YOU I WASNT A GOOD TEACHER LOL please forgive me....

SURE there are unsafe scenarios BUTTTTTTTTTTTT the one in this thread IS PREVENTABLE by protecting wire with the proper NOT NEARLY TWICE AS BIG overcurrent protection device as established by the NEC

Finally for the risk takers use what you please,,,,,,,,,,the risk is low if you're okay taking it,,,,,,,,,,,,BUT FOR THOSE INDIVIDUALS WHO FAIL TO UNDERSTAND THE RISK INVOLVED IN USING 30 AMP WIRE FROM THE 50 AMP BREAKER PEDESTAL TO THE RV MAIN BREAKER     what can I say LOL

I challenge anyone to explain how the use of 30 amp rated wire from the 50 amp breaker in the pedestal to the RV panel is NOT a "preventable" risk ????????????? Good luck finding anything that says "Oh its fine to allow enough current to degrade or even melt the insulation, go ahead and use 30 amp wire where 50 amps can flow  YEAH RIGHT GOOD LUCK WITH THAT ONE

PLEASE PLEASE PLEASE USE WHAT YOU LIKE AND TAKE WHAT RISKS YOU LIKE even if you cant grasp what overcurrent protection is all about. But if you can and want to lower the risk ADD A 30 AMP FUSE, thats so cheap and easy and may save a life or prevent a fire.

 

QUESTION FOR EVERYONE: Would anyone here who has a 50 amp 4 conductor RV that had a bad cord replace it with a 30 amp 4 conductor cord????????????????? Why not, the risk is low, no problem with 30 amp wire on a 50 amp breaker right ???? ANSWER THAT ONE WILL ANYONE !!!!!!!!!!!!!!!!! 

 

If trying to help everyone and educate and maybe save a life or prevent a fire is a bad thing JUST CALL ME BAD LOL Its well worth it to me.

 

God Bless all here and keep safe, happy travels to yall HEY I DID TRY MY BEST and trust its appreciated. I appreciate all those who help me here, a fine group of polite professionals hang out here which is why I try to help when I can

PS Jack you're right, overcurrent protection IS INDEED covered by the NEC, thanks for pointing that out, I appreciate it. There are a fine group of engineers electricians and electrical technicians here and I know I'm NOT the ONLY person who understands how and why and the theory of how its  unsafe to use 30 amp rated wire on a 50 amp protected circuit from pedestal to the RV I'm NOT talking how unsafe,,,,,,,,,, or how low or high the risk,,,,,,,,,,,,,,,, or how there may never be a problem ONLY trying to explain the reasons and theory and how the NEC (not me) determines its indeed an unsafe situation. Argue with them not me lol but it is AN EASILY PREVENTABLE RISK if its not already fixed in the dogbone via a fuse wire or fuse link, heck maybe it is?

 

John T  

[I'mdonewiththis forum]

59 minutes ago, oldjohnt said:

QUESTION FOR EVERYONE: Would anyone here who has a 50 amp 4 conductor RV that had a bad cord replace it with a 30 amp 4 conductor cord????????????????? Why not, the risk is low, no problem with 30 amp wire on a 50 amp breaker right ???? ANSWER THAT ONE WILL ANYONE !!!!!!!!!!!!!!!!! 

 

John T  

I can see some um, shall we say some "uneducated people" attempting to do just this. After all, wire is wire, right? They look at the wire and it says "600V" on it so they figure they will be fine............. 

[oldjohnt]

Great point Tom, hey its good for 600 volt lets use it lol NO PROBLEM using 30 amp 4 conductor wire is just fine on my RV plugged into a 50 amp breaker, after all, the risk (albeit still preventable) is so very very small right ???????????? Theres sort of a reason they make different size breakers appropriate for certain size wire now think about it............. 

Were all gentlemen here so lets just agree to disagree and maintain respect and courtesy is fine by me, I say its unsafe BUT AN EASILY PREVENTABLE RISK, others can say its not, do as anyone pleases, the risk is theirs, NOT ours. 

Thanks Tom, best wishes and God Bless

John T

[mptjelgin]

4 hours ago, oldjohnt said:

QUESTION FOR EVERYONE: Would anyone here who has a 50 amp 4 conductor RV that had a bad cord replace it with a 30 amp 4 conductor cord????????????????? Why not, the risk is low, no problem with 30 amp wire on a 50 amp breaker right ???? ANSWER THAT ONE WILL ANYONE !!!!!!!!!!!!!!!!! 

Apples and oranges...  My current fifth wheel is set up for 50 amp service, and I regularly draw over 30 amps on one or both legs, sometimes for hours or perhaps even days at a time. Knowing this, I certainly wouldn't replace my cord with a 30 amp cord.

However, my previous fifth wheel had a 30 amp service, and I never drew over 30 amps based on the readout on my EMS. On the rare occasions where I stayed at an RV park with only 50 amp receptacles I used my 50-to-30 amp adapter without hesitation. In fact there were times where 30 amp service was available but I still used the 50 amp circuit and adapter as the 30 amp circuit was marginal and the 50 amp circuit more robust. Would you argue that staying with a weak 30 amp circuit and the accompanying voltage drop is smarter or safer?

Using a 50-to-30 amp adapter on a 30 amp trailer is no way is the equivalent of putting a 30 amp cord on a 50 amp RV, and then intentionally overloading that 30 amp cord for hours/days at a time. Not even close.

[avvidclif]

I guess I'm missing something. Not being the electrical injunir. If I use a dogbone to plug into a 50A outlet and then plug a 30A cord into the dogbone that would be an unsafe condition IF I put a 50A load on the other end or could put one.

But what if on the other end of the 30A cord is a 30A breaker limiting the load on the cord to 30A. Where is the unsafe condition? I can't draw more than 30A thru the 30A cord because of the 30A breaker on the load end.

I'm not trying to use a dogbone 50-30 to power a 50A RV.

[Kirk W]

34 minutes ago, avvidclif said:

But what if on the other end of the 30A cord is a 30A breaker limiting the load on the cord to 30A. Where is the unsafe condition? I can't draw more than 30A thru the 30A cord because of the 30A breaker on the load end.

Exactly! And that is what both Jack & I are saying and both of us have many years of practical experience as working technicians. Some things are just common sense. I would add that the person asking the question gave up last Tuesday. Let's hope that he hasn't given up on the forums. 

[avvidclif]

And pray tell why would anyone use a 50-30A dogbone connected to a 30A cable and then adapting back to a 50A to plug into a 50A rv? I see nothing said about that, all I saw was you can't use a 50-30 dogbone safely. Irrespective of what is on the other end.

FWIW I don't have a 50-30A dogbone. I have a 30A cable and a 50A cable, both can connect to the RV which is 50A. The 30 goes into the 30 hole and the 50 into the 50 hole. And extensions for both.

[Randyretired]

Plugging an undersized cord into a receptacle with the capability to overload the cord is a very common situation.  It always creates a slight but uncommon risk.  Right now the lamp and TV we have on are fed through cords that are not rated for the 20 amp breaker powering these.  An extreme example is the wire typically supplied with Christmas lights.  As I weigh the risks involved those cords inside would seem to be the most dangerous because of the fire risk and people (kids) are more likely to be present.  I agree with John that there is a real risk but it is one most of us live with every day.  

[I'mdonewiththis forum]

6 hours ago, avvidclif said:

I guess I'm missing something. Not being the electrical injunir. If I use a dogbone to plug into a 50A outlet and then plug a 30A cord into the dogbone that would be an unsafe condition IF I put a 50A load on the other end or could put one.

But what if on the other end of the 30A cord is a 30A breaker limiting the load on the cord to 30A. Where is the unsafe condition? I can't draw more than 30A thru the 30A cord because of the 30A breaker on the load end.

I'm not trying to use a dogbone 50-30 to power a 50A RV.

What John is saying is that even though you have had no problem plugging into and running off of the 50A plug, your power cord is not protected against over amperage. The cord is rated for 30A and your over current protection device is 50A. In the RARE event that a power cord is damaged and leaking voltage (it may not even show any evidence of damage) there is a POSSIBILITY of having a serious issue and recommends against using 50A to protect a 30A cord. A scenario may be that there is a small break in the outer covering and a puncture in the black wire's insulation from being stepped on. It will be fine when dry, but IF it rains and IF that particular part of the cord is in a puddle then it can leak voltage and amperage into the earth. If you are at a high draw situation in your 30A trailer you could possibly have 35A or more flowing through the cord. There are a lot of things that have to be in play for it to happen, but it is possible. He isn't attempting to argue, just pointing out the POTENTIAL safety issue.

[57becky]

Not trying to confuse the issues being discussed, and they are very valid issues, but another thing not understood is, all the breakers inside our rigs and in the pedestals have a 10,000 amp fault duty rating, meaning they are designed to handle momentary fault current, which can get very high.  You wouldn't want a breaker to blow up from a fault, because it wouldn't work to protect anything.  Also, fuses and breakers have different ratings when it comes to duty current and fault current.  A breaker and fuse is designed to handle the maximum rated current continuously, but it will trip very fast in a fault situation, so, a 50 amp breaker connected to a 30 amp load will trip when it sees a fault, and yes, there will probably be damage to wiring on the load side, but the breaker will not stay closed and keep the fire going.  Just for anyone's curiosity, I am a retired lineman from a large California utility, and I have seen some very weird things happen with electricity at voltages from 120 volts all the way up to 500,000 volts.  This conversation is one of the best, as it exposes anyone willing to read it to the potential hazards associated with electricity, and hopefully keeps us all safe.

[avvidclif]

What the NEC (and John) is saying is you should not plug any cord into an outlet unless the cord is rated for the same current as the breaker protecting it. I can see that in a hardwire situation to the outlet but not an extension cord. That would mean every cord I plug into a 20A protected socket would have to be 12GA, no matter what it's powering. If that's the case the NEC has lawyered up and lost common sense. (Seems to be a lot of that around, lawyering up). Don't stick your foot or hand under the deck of a running lawnmower....DUH

If the 30A cord has a break and draws excess current to the extent it burns;

1. The 50A breaker will trip,

2. The cord is outside and not inside the RV therefore the risk to the RV is minimized, maybe a burned spot on the grass.

That's the same risk I take when I plug a 16ga extension cord into a 20A outlet, done every day.

[oldjohnt]

OUTSTANDING RECENT ADDITIONS, I

 

[oldjohnt]

• OUTSTANDING RECENT ADDITIONS, I was on the road in the RV a day or so and missed a bit so here goes THANKS EVERYONE who are weighing in.

• If you know more about electrical safety then the NEC and are willing to bet your life on it ITS YOUR RISK  if you think its no problem !!!!!!!!!!!!!!!!!!!!!1

It appears at least some of the fine gents are finally understanding my NEC overcurrent protection safety concerns and the hazards and the risks involved if using ONLY 30 amp rated cords in a 50 amp circuit from the pedestal to the RV whewwwwwwwwwwwwww lol  I know darn well no one with any common sense would replace a 50 amp RV cord with one rated for ONLY 30 amps under the theory OH ITS SUCH A SMALL RISK AND THERES NO PROBLEM    If anyone dares to take the risk of using a 30 amp cord in the circuit from the pedestal to the RV via a dogbone THEYRE DOING THE VERY SAME THING as if they replaced their 50 amp cord with one rated for only 30 NOW WHO HERE WOULD DO THAT LOL

 

Any takers who will defend its okay and low risk and is fine to replace their 50 amp RV power cord with 30 amp wire ???????????????? Why not for those who say its okay to use a dogbone  which does the same thing LETS HEAR FROM YOU !!!!!!!!!!  Would you replace 50 amp wire with 30 ?????

 

ALSO to address another issue over which there appears to be some misunderstanding is as follows:

 A fault caused current draw hovering around 50 amps in an only 30 amp rated cord DOES NOT INSTANTLY TRIP THE BREAKER. The Thermal portion of a Thermal Magnetic breaker takes a long time before it trips UNLIKE the Magnetic which indeed trips almost instantly under a direct short THEREFORE the hazard and prevention  IS NOT like those who say OH A SHORT WILL TRIP THE 50 AMP BREAKER SO NO PROBLEM 

BUT  THE PROBLEM IS 50 AMPS IN 30 AMP WIRE CAN MELT THE INSUALTION AND A HOT WIRE CAN BE EXPOSED TO WATER OR EARTH IN WHICH THE CORD LAYS AND KILL YOU DEAD AND THE 50 AMP BREAKER WONT STILL TRIP unless there's a dead high current short

SOOOOOOOOOOO those who think there's no problem cuz the 50 amp breaker still trips that's only under a near dead short condition buttttttttttt they don't understand 50 amps in 30 amp wire can melt the insulation (still not trip the breaker unless a dead short) and expose a hot wire WITHOUT TRIPPING THE BREAKER and a hot live wire in water or the dirt or near the RV CAN KILL YOU OR YOUR GRANDCHILD DEAD

MY SINCERE APOLOGY Listen all you fine gents I just CAN NOT teach my lifes work and the NEC to a person who hasn't worked with the NEC and was educated in power distribution design  HERE ON A FORUM. Yall keep bringing up arguments or good thoughts that sound good UNTIL YOU HEAR THE THEORY AND NEC just as above as to why your thoughts aren't fully correct BUT THATS NOT ANYTHING AGAINST YOU DO NOTTTTTTTTTT TAKE OFFENSE FOR MY TRYING TO HELP AND EDUCATE.

•  

• There are some fine long experienced electrical techs and practitioners here who I respect as they do me and even if they RV for 40 years or were technicians THEY DID NOT STUDY, PRACTICE, DESIGN, POWER DISTRIBUTION AND WORK WITH AND FULLY UNDERSTAND OVER CURRENT PROTECTION NOR TAKE NEC TRAINNG SEMINARS.

I just cant keep up with yall lol there are valid NEC and safety reasons to dispute and correct many of the arguments above as to how and why ITS Unsafe, a hazard, and an NEC violation to use 30 amp rated wire  protected by a huge 50 amp breaker BUT YOU WILL HAVE TO READ STUDY WORK WITH THE NEC AND PRACTICE POWER DISTRIBTIION A BIG PART OF YORU LIFE BEFORE YOU UNDERSTAND IT AS WELL AS MYSELF. That's NOT to brag just to point it out

Use common sense, take all the risks you wish  but those that are so known and predictable and as easily corrected  as above makes no sense to me to be unsafe and take the risk which may kill someone

ITS UNSAFE, HAZARDOUS, AN NEC OVERCURRENT PROTECTION VIOLATION TO USE 30 AMP WIRE IN A 50 AMP CIRCUIT FROM PEDESTAL TO RV

EVEN IF ONE CANT UNDERSTAND WHY as I do

And that's so even thought I cant explain it lol and still unsafe even if a low risk BUT FOR THISE WHO ARE WILLING TO ACCEPT HALF A$$ WIRING TO THEIR RV and take a chance just do it !!!!!!!!!!!!!!!!!!!!!!!! and 40 years of doing it that way and never a problem and thinking youre smarter then the NEC board of experts MAY GET YOU KILLED so are you willing to bet your life the NEC is wrong ???????????????????

Thanks to everyone and my apology for not being able to teach this but it does appear a few here are finally understanding the hazards of 30 amp wire in a 50 amp circuit yayyyyyyyyyyy if I taught one person or saved a life its worth it

John T Retired Electrical Power Distribution Design Engineer, NOT a plumber or carpenter or an ELECTRONIC tech but an Electrical Power Distribution practitioner

God Bless I hope I helped educate at least some of you, the others no offense intended but I give up lol  still PLEASE be safe and dont take my word for this consult the NEC

If you go against the NEC you're betting your life remember ITS YOUR RISK don't take my word for it............take your arguments up with them

[Dutch_12078]

John, in digging through the 2017 edition of the NEC, I can easily find references to what breaker protection is required for a 50 amp outlet in an RV park, and even references to the minimum number of 50 amp outlets they should have, but nowhere in section 551 or anywhere else do I find anything that specifies the minimum wire size that can be plugged into an outlet. The NEC does specify that power cords must be sized adequately for the maximum expected load, but nothing about the source capacity. It is interesting though, that in various charts the NEC rates 10ga copper wire for 30 amp, 40 amp, and 55 amp use in various applications. I think the bottom line here is that the risks in using a 50-30 amp adapter when needed are so infinitesimally small that they're not worth loosing any sleep over. We take bigger risks just stepping out our doors every day.

[mptjelgin]

2 hours ago, oldjohnt said:

•  I was on the road in the RV a day or so ...

 

Now THERE is a real risk. Compared to what has been beaten to death in this thread, being on the road is a true risk that is exponentially more likely to get you killed than using a 50-to-30 amp connector.

2 hours ago, oldjohnt said:

• Any takers who will defend its okay and low risk and is fine to replace their 50 amp RV power cord with 30 amp wire ???????????????? Why not for those who say its okay to use a dogbone  which does the same thing LETS HEAR FROM YOU !!!!!!!!!!  Would you replace 50 amp wire with 30 ?????

 

 

I did address it in a post above, but apparently you either didn't read it or chose not to address it. It is a silly comparison and one that adds nothing to this discussion. 

[avvidclif]

I think he ignores anything that doesn't conform to his beliefs. Likes to shout also.

[oldjohnt]

The risk is very small  but its sooooooooooo easily preventable, IS IT WORTH RISKING YOUR LIFE?????

Over many many years I have noticed that Electrical POWER DISTRIBUTION design engineers, professional electricians, professional POWER DISTRIBUTION Technicians (NOT talkin electronics work)  that have studied, used, worked with the NEC and attended numerous seminars all understand the risks of improper overcurrent protection and all agree wire rated for ONLY 30 amps should be overcurrent protected at 30 NOT 50 amps. Sure a dead short will still trip a 50 amp breaker HOWEVER its that rare resistive short NOT ENOUGH to draw over 50 amps (breaker don't trip) but near CAN MELT THE INSULATION and a live hot wire can be exposed to water or earth or the RV or worst your barefoot grandkids AND KILL THEM DEAD.

Also if its such a low risk its much cheaper to replace a 50 amp cord with a 30 amp rated BUT I BET NO ONE WOULD DO THAT and say its such a low risk YEAH RIGHT.

Its the gents who don't know, understand and haven't studied the NEC and practiced power distribution for years who think they more then the NEC who ridicule or mistakenly think its not a problem THEY JUST DONT UNDERSTAND and I sure cant teach here what takes yearsssssssssssss of study and practice and works experience to comprehend and I don't expect them to BUT THAT DONT MAKE THEM A BAD PERSON they just don't understand over current protection and the hazards involved if you violate the NEC. A person who isn't a doctor or lawyer or carpenter or plumber go to them for professional advice, BUT if it comes to the NEC they know it all and MORE then the NEC and maybe just enough to get them killed !!!!!!!!!!!! 

Lets closed this out, I have helped and educated many of you, maybe not a few, but hey I tried my best but I'm  a poor NEC teacher grrrrrrrrrrrrrr my bad

WE ALL AGREE THE RISK IS LOW (but easily preventable) and if you're willing to bet your life you know more the then NEC and mistakenly see no problem with 30 amp wire in a 50 amp protected feeder from the pedestal to the RV panel SORRY I CANT HELP YOU but if I helped only one person ITS WORTH MY EFFORT AND ID DO IT AGAIN. Sure its a low risk but how would you live with yourself if a person read your opinion and conclude its okay so they ignore the NEC and their grandkid got electrocuted !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Yall can take that risk and bet your grandkids lives BUT NO WAY IM GOING ON RECORD AND SAY SURE USE 3O AMP WIRE FROM PEDESTAL TO YOUR RV   It violates the very purpose and intent of overcurrent protection in the NEC which while lay persons may NOT understand  professional sure do, and I after years of study and NEC practice and experience SURE DO and hey I taught a few of you at least,,,,,,,,,,,,,,,,,,

I AGREE WE ALL AGREE the risk is lowwwwwwwwwwwww but it ONLY takes one mishap to kill you dead and its easily preventable so pleaseeeeeeeeeeeeeeeee pleaseeeeeeeeeeeee don't use 30 amp wire in a 50 amp protected feeder from pedestal to RV main panel

Best wishes, God Bless and keep yall safe and take what risks you're willing to and just because we all dont agree dont mean I don't respect and appreciate all opinions even if they dont agree with the NEC and overcurrent protection basics. I trust yall appreciate and respect my expertise and that I tried my best to help IF IT SAVES A LIFE ITS WELL WORTH IT...............

Kepe safe and happy travels

John T  BSEE, JD  retired electrical power distribution design engineer and long time NEC student and practitioner    

 

[mptjelgin]

2 hours ago, oldjohnt said:

Also if its such a low risk its much cheaper to replace a 50 amp cord with a 30 amp rated BUT I BET NO ONE WOULD DO THAT and say its such a low risk YEAH RIGHT

 

To summarize my comments in two separate posts above regarding this red herring that you keep presenting:

"Apples and oranges." 

"Using a 50-to-30 amp adapter on a 30 amp trailer is no way is the equivalent of putting a 30 amp cord on a 50 amp RV, and then intentionally overloading that 30 amp cord for hours/days at a time. Not even close."

"It is a silly comparison and one that adds nothing to this discussion. "

Brief and concise.

[Darryl&Rita]

And the NEC does allow several uses of protection GROSSSLY oversized to conductors ampacity, that haven't been addressed, either.

[oldjohnt]

4 hours ago, Darryl&Rita said:

And the NEC does allow several uses of protection GROSSSLY oversized to conductors ampacity, that haven't been addressed, either.

EXAXCTLY thanks for pointing that out. In fact I think in certain motor branch circuits in order for the motor to start you could use up to something like 175% oversized breaker PROVIDED THAT the motor had proper thermal overload protection.

So if anyone cant understand how using a breaker nearly twice as large of the conductors ampacity in the feeders from the pedestal to the RV main panel IS NOT UNSAFE AND A POTENTIAL HAZARD I tried but I just failed to educate you but that's wiith all due respect to both of us, we can just agree with the NEC's overcurrent protection o/r we can choose to ignore it and take the associated risks, why take a risk that's so preventable is my thought, why not do it RIGHT AND SAFE versus take a chance even if its small.

THANKS TO EVERYONE, I appreciate and am glad I helped explain NEC and overcurrent protection which many of you were able to grasp. Your risk your choice to use proper sized overcurrent protection per the NEC or ignore it at your own peril.

Be safe, God Bless all

 

John T

[Dutch_12078]

6 hours ago, oldjohnt said:

EXAXCTLY thanks for pointing that out. In fact I think in certain motor branch circuits in order for the motor to start you could use up to something like 175% oversized breaker PROVIDED THAT the motor had proper thermal overload protection.

Which is EXACTLY the situation we have when we use a 50-30 adapter, John. Like the motor branch circuit, the source breaker is larger than the intermediate wiring calls for, but like the motor's thermal cutout, the connected load has its own protection of the proper rating.

[oldjohnt]

8 hours ago, Dutch_12078 said:

15 hours ago, oldjohnt said:

 

Which is EXACTLY the situation we have when we use a 50-30 adapter,

Good discussion Dutch, I really appreciate and enjoy your comments HOWEVER I have to with all due respect disagree

The ONLY exception I recall is for motor control circuitry NOT ANY, OTHER APPLICATIONS and the reason why was a "standard" breaker would trip upon motor starting due to the fact the initial starting surge current could be 5 to 6 times the run current THEREFORE IF AND ONLY IF it was a motor branch circuit NOT a feeder to a panelboard and if and only if the motor had proper thermal overload protection  DID THE NEC ALLOW THAT EXCEPTION.

 

What I'm so happy for is that prior to this discussion may fine lay persons did not even understand how and why using 30 amp rated cored with a 50 amp breaker WAS SUCH A HAZARD, They had no clue but now I think everyone here at least recognizes and understands how and why its dangerous and why a person shouldn't use 30 amp wire in a 50 amp protected circuit ESPECIALLY with a rubber cord laying in the water or on sharp rocks FROM the pedestal TO the RV main panel ITS JUST NOT SAFE DARN IT LOL but I agree 100% the RISK IS SMALL   At lease we can allllllllllllllllll agree on that lol

For sure I'm here only to help not bicker and unless a person has spent much of his lifes work and career in training and experience and working daily with the NEC I DONT EXPECT THEM TO UNDERSTAND OVER CURRENT PROTECTION but to me (even though not lay persons) it seems so obvious if you use 30 amp rated wire you need a 30 NOT a 50 amp breaker in a feeder from the pedestal to a main panelboard ESPECIALLY wire laying on the ground that can get run over or stepped oN by your barefoot grandchild............

It has been a good learning experience for many while boring grrrrrrrrrrr to others for which I apologize, but at least by now most realize the potential hazard plus the reasons why.

I really really appreciate your thoughtful comments and have enjoyed our discussion, I can tell youre quite up on electrical safety. For those who still aren't and see no problem using only 30 amp wire in a 50 amp protected outdoor feeder circuit sorry I failed as a teacher but you must admit I did try yet I cant impart the whole NEC and my lifes study and experience here on a forum HECK NO TEACHER IS THAT GOOD LOL

In closing I think we can all agree there is a hazard (30 amp wire in 50 amp feeder) BUT WE CAN RESPECTFULLY AGREE TO DIAGREE HOW MUCH OF A HAZARD IT IS  Okay gang ????????????????????????????????  But I'm just not willing to go on record as an electrical power distribution design engineer and past NEC practitioner and say its fine no problem low risk when its so easily preventable (add a fuse or fuse wire link if not already there)  while being safe (and I say NEC compliant) can prevent a fire or save a life. Those who are risk takers or are willing to get by with less then safe can do as they please............

THANKS SO MUCH to Dutch and alllllllllll others and I'm happy I'm able to help on here where others have helped me soooooooooo much. I sincerely respect and appreciate everyones opinions as I trust they in return do mine, I try my best but like all mortals make mistakes, who here is perfect and doesn't do likewise???? 

God Bless and keep everyone safe RESPECT ELECTRICITY it can kill you dead grrrrrrrrrrr

John T  BSEE, JD 

8 hours ago, Dutch_12078 said:

the connected load has its own protection of the proper rating.

PS Buttttttttttttttttt while the connected load has proper rating ITS NOT THERE AND DOWNSTREAM OF THE LOAD OR RV MAIN PANEL PROTECTION WERE CONCERNED WITH,,,,,,,,,,,,, ITS THE RUBBER CORD LAYING ON THE GROUND OR IN WATER THAT GETS RAN OVER OR STEPPED ON that's a potential hazard if the wire is rated 30 amps yet its a huge 50 amp breaker !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Dutch_12078]

And again, John, the only concern in that case is with the highly unlikely event that the damaged cord occurs only when the cord is plugged into a 50 amp outlet, since in any other situation where the damage occurs when plugged into a 30 amp outlet, or even a 15/20 amp outlet, the risk can also be lethally hazardous. Since the risk is extremely small even when plugged into a 30 amp outlet or smaller, I think the risk becomes nearly non-existent in the very limited circumstances you're concerned about. It's really sounding a lot more like "lawyer speak" at this point, than sound "risk/reward" consumer oriented engineering. At some point, a design engineer likely determined that including 30 amp protection in a 50-30 adapter did not meet the cost/benefit goals of the product.

[oldjohnt]

Good points Dutch, Sure as one who practiced power distribution much of his life and studied and used the NEC faithfully, I tend to be extra safe when it comes to life safety ESPCEIALLY when a hazardous situation is so easily preventable. At least after all this exercise (Thanks to you and all for their help)  many who didnt even understand the NEC and overcurrent protection can see why using 30 amp rated wire in a 50 amp feeder from the pedestal to the RV main panel IS A HAZARD (albeit yes small risk) and why the use of 30 amp wire protected by a much larger 50 amp breaker violates the very essence of the NEC's overcurrent protection.

 In my years of practice and study I just saw toooooooooooooooo many examples where a life was lost or a fire occurred because someone thought OH THE RISK IS SMALL or what does the NEC know lol I'm smarter then they are AND IT GOT THEM KILLED !!!!!!!!!!!!!!!!

Its those small unforeseen risks that start fires or get one electrocuted in so many cases 

I AGREE 100% the risk is in the cord BUT that's what's laying in water or on the ground or on sharp rocks and gets run over or kids step on YIKES      But that's the very reason the NEC theory of overcurrent protection is there so there cant be enough current to overheat and melt the insulation (Still NOT a dead short to trip the 50 amp breaker) so a hot live wire can be exposed to water or earth or the RV. If it were a proper 30 amp breaker there cant be enough current to ruin the insulation cuz it can pass 30 without damaging it.

SUMMARY why take a life risk even if its small while its easily preventable?????????????????? I prefer to err on the side of safety myself but if a person is willing to take that small risk they may end up paying the ultimate price IS IT REALLY WORTH IT ask yourself, IS IT ?????????????????????????????????????

That's the reason I have to go on record as pleading with people to NOT take that risk,,,,,,,,,,,,I have to go on record as educating and explaining the risk to non sparkies,,,,,,,,,,,,,,,,,,,,,,And even though I'm a poor teacher and cant explain power distribution and overcurrent protection (BUT who can do that lol) to non electrical power distribution gents HEY I TRIED GIVE ME THAT

Use what you please, take what risks you're willing to take YES ITS SMALL but think twice before using 30 amp rated wire in a 50 amp circuit to your RV  I BEG EVERYONE NOTTTTTTTTTTTTTT TO DO THAT that small risk may cost you dearly !!!!

THANKS SO MUCH DUTCH you took the time to understand and help and provided great insight and I respect your and anyones   right to do as you please and take what risks you like and I expect in return my right to try and help and educate the fine gents here and explain the risks and the NEC and overcurrent protection IF IT SAVES ONE LIFE OR PREVENTS A FIRE IM GLAD TO DO IT and thanks to all who participated and asked good valid questions I tried my best to answer.   

CAN WE ALL AGREE THE RISK IS SMALL I (0ne who spent much of his life in the electrical and NEC and safety areas) think it is and I'm no longer willing to  take it but others sure are........

God bless all and keep safe now, hear me do NOT do as I suggest, consult the NEC it can save your life

THANKS to all who took part in this fun and educational discussion. As gentlemen and professionals we can agree to disagree

John T