50 amp to 30 amp

[Vicr]

Why is it that "Electrical" threads go so sideways? I design and build electrical distribution systems for a living and have been in the trade since 1983. The company I work for has clients like Amazon and Boeing and those people trust their electrical system to ME. I might be considered an expert by some, I really don't care about titles I just do my job. On almost all these "electrical" threads there is some good information and then a lot of bad "information". If you are not 100% sure with your "opinion" why not just let some of us who actually know how these systems work, what the code is, know how to do load calculations etc answer, and then maybe you can learn something. I've been teaching electrical apprentices for over 30 years and the number one thing I tell them is "listen to me when I'm talking so you can learn".

[TaftCoach]

Originally Posted by Vicr

Why is it that "Electrical" threads go so sideways? I design and build electrical distribution systems for a living and have been in the trade since 1983. The company I work for has clients like Amazon and Boeing and those people trust their electrical system to ME. I might be considered an expert by some, I really don't care about titles I just do my job. On almost all these "electrical" threads there is some good information and then a lot of bad "information". If you are not 100% sure with your "opinion" why not just let some of us who actually know how these systems work, what the code is, know how to do load calculations etc answer, and then maybe you can learn something. I've been teaching electrical apprentices for over 30 years and the number one thing I tell them is "listen to me when I'm talking so you can learn".

I went back to see what you posted and I'm not seeing your original post.

[Vicr]

Originally Posted by TaftCoach

I went back to see what you posted and I'm not seeing your original post.

This is my first post to this thread.

[TaftCoach]

Originally Posted by Vicr

This is my first post to this thread.

Sorry, then I'm confused. You are wondering why people aren't listening to you or not listening to someone else?

[RetiredOne]

Originally Posted by Vicr

Why is it that "Electrical" threads go so sideways? I design and build electrical distribution systems for a living and have been in the trade since 1983. The company I work for has clients like Amazon and Boeing and those people trust their electrical system to ME. I might be considered an expert by some, I really don't care about titles I just do my job. On almost all these "electrical" threads there is some good information and then a lot of bad "information". If you are not 100% sure with your "opinion" why not just let some of us who actually know how these systems work, what the code is, know how to do load calculations etc answer, and then maybe you can learn something. I've been teaching electrical apprentices for over 30 years and the number one thing I tell them is "listen to me when I'm talking so you can learn".

So, why type a big paragraph telling us that you're an expert?

Originally Posted by Vicr

This is my first post to this thread.

Maybe, you then can opine on the OP post instead, and share your knowledge, instead of lecturing other people who are trying to learn.

Originally Posted by TaftCoach

Sorry, then I'm confused. You are wondering why people aren't listening to you or not listening to someone else?

I wondered the same thing....

[Vicr]

The OP's question was answered in post #2.


I'm a long winded "expert" who does lecture. There have been hundreds of times in my career that my lecture has kept someone or an entire crew alive and out of the burn ward. My primary function as far as my electrical knowledge is to keep people safe and that is done primarily thru building to NEC guidlines and practices enforced by the NFPA.

[TaftCoach]

Originally Posted by Vicr

The OP's question was answered in post #2.


I'm a long winded "expert" who does lecture. There have been hundreds of times in my career that my lecture has kept someone or an entire crew alive and out of the burn ward. My primary function as far as my electrical knowledge is to keep people safe and that is done primarily thru building to NEC guidlines and practices enforced by the NFPA.

Off this topic. Yet even electricians will argue what the appropriate solution is. I've been involved with approving bids from enough electricians to know that there is always a good, better, best option. First guy in might say that 12 gauge extension cord is adequate, meets code, and will work just fine. Another electrician comes in and says, yes, but for a few pennies more I'd go 10 gauge for a little extra safety. Finally the third guy comes in and says if you want to save money, sure go with that extension cord, but one fire from an exposed cord, or one person tripping, and you'll wish you paid me to install a receptacle instead of using an extension cord. So if hear someone in that situation again I'll perhaps offer the suggestion to consider installing a receptacle instead of listening to the first guy. Of course I'm not going to offer any advice on how to do it, just to consider it.

I've even listened to two old timers argue about how to wire a simple light fixture.

If you are wondering why someone would continue the conversation after hearing from an expert I can offer this analogy. When I was diagnosed with cancer I sought out a second opinion. If I would seek a second opinion after consulting an Ivy League educated, award winning, specialist, I might even question a plumber or electrician.

But I think we would all agree, your credentials means I'll listen to your opinion on electrical design and implementation ahead of a lot of people offering lay person advice. And like many areas, bad advice here could be life altering.

[Vicr]

I've always said: If you give 12 journey wiremen the same exact task it will get done 12 different ways, but all to code.

[TaftCoach]

Originally Posted by Vicr

I've always said: If you give 12 journey wiremen the same exact task it will get done 12 different ways, but all to code.

And they all will insist theirs is the only correct way lol.

One thing I did develop managing facilities is I trusted the average electrician and electrical system and distrusted the average plumber. Nothing against the people but I figure a problem with the electric and something will (probably) pop. Pipes behind walls and under floors that develop a problem ruin my sleep for weeks.

[qs271a]

As an electrician of over 35 years I will tell you that those dog bones have to be built to National electrical code standards. When you're hooking those dog bones into a 50 amp service, you're connecting into only one side of that service. Always remember that your draw will always be whatever the trailer has been rated for. Thanks and happy camping.

[Cavie]

Originally Posted by qs271a

As an electrician of over 35 years I will tell you that those dog bones have to be built to National electrical code standards. When you're hooking those dog bones into a 50 amp service, you're connecting into only one side of that service. Always remember that your draw will always be whatever the trailer has been rated for. Thanks and happy camping.

LOVE IT! Now help me convince the RV world that 50 amps service is 240 volts and to stop saying 100 amps available!!!!

[RetiredOne]

Originally Posted by qs271a

As an electrician of over 35 years I will tell you that those dog bones have to be built to National electrical code standards. When you're hooking those dog bones into a 50 amp service, you're connecting into only one side of that service. Always remember that your draw will always be whatever the trailer has been rated for. Thanks and happy camping.

True, you're connecting to one side, which is still 50 amps for a 30 amp rig.

Originally Posted by Cavie

LOVE IT! Now help me convince the RV world that 50 amps service is 240 volts and to stop saying 100 amps available!!!!

It is 100 amps, 50 amps EACH leg, that's why it's a double pole 50.

[Cavie]

Originally Posted by RetiredOne

True, you're connecting to one side, which is still 50 amps for a 30 amp rig.



It is 100 amps, 50 amps EACH leg, that's why it's a double pole 50.

You do know your talking to a 45 year master electrician right?

[Vicr]

Originally Posted by RetiredOne

True, you're connecting to one side, which is still 50 amps for a 30 amp rig.



It is 100 amps, 50 amps EACH leg, that's why it's a double pole 50.

You don't have 100 amps available on a 50 amp service, period. There is a double pole breaker because you have two opposing phases of electricity. Why do you argue with electricians?

[pitman44]

Originally Posted by RetiredOne

I think you're going the wrong way with your adaptors, it would go like this:


First, 50 amp female to 30 amp male:


Doing it this way, the maximum draw would be whatever the 115 volt line on the house can provide (15 or 20 amp). If he tried to fire up multiple appliances (using the normal 50 amp circuits) in the rig, it would probably pop the circuit breaker in the house.

Perhaps I'm mistaken, but it sounded to me that the OP was connecting the 30A line on his camper to a 50A pedestal receptacle. So the opposite way around. 50A male/30A female. Seems that the downstream wire, camper cord, would be undersized, but would it matter if there's a 30A breaker immediately after the cord? Probably not.

[JimD]

I don't want to get in the argument of 50 amp or 100 amp as I am not a licensed electrician. I have wired my house for a 220 air compressor and another for a welder without blowing anything up. Sure glad my rig is only 30 amp.

Can a specialist confirm my hypothesis on what I would like to believe is true.

The 240 being fed to the RV is indeed 240 volts but is used once inside as 120 volts. Each leg of the 240 is fed to different areas of the RV as 120. Each "hot" leg is used along with the neutral wire that is fed to the outlet which nets 120 volts.

If you measure across the two hot leads you will get 240 volts. You could, in theory operate a 240 volt item (welder) off that 240 volts and be fused at 50 amps. The 50 amp breakers are ganged together so if one goes they both do.

Now for my hazy area. Your house has 240 volt service which splits each leg into different areas of your house Each line is fused at 20 amp or 15 typically and all operate independently of each other. Isn't that is what is happening here? Each individual line is fused at 50 amps independent of the other line. Granted the breakers are ganged together but that only comes into play if one trips.

So, we have 2 independent lines feeding the RV. Each line has a 50 amp breaker therefore it would allow 50 amps to flow through each line. So, you have 2 individual lines each fused at 50 which would give you a total of 100 amps.

Am I correct in my thinking? I don't think an RV would ever be pulling 100 amps. Also, is the neutral wire capable of flowing 100 amps if each leg was pulling 50?

Oh, the things that keep me awake at night. I never really thought much about the 50/100 amp controversy but now I am curious.

[Cavie]

jimD You almost have it right. 240 volts is delivered to 50 amp RV's. MOST of the RV panels (except for very high end MH) are made in such a way that you can not plug in a 2 pole breaker except for the MAIN. Therefore you can not access 240 volts. 240 volts is across L1 and L2 but that's it. No 240 access with 2 pole breakers.

It's not that the different legs are run thruout your house. It's 120 on Buss bar A (L1) and 120 on Buss bar B (L2). If your house has a 200 amp service. You say "I have a 200 amp service" correct? Guess what? It's just like the RV. 120 down each leg. BUT your hose panel is made just like the High End MH. You can access 240 volts with a 2 pole breakers.

You will never hear an electrician say 100 amps available. On the technical side it is correct BUT what nobody understands is IF one leg goes over 50 amps the main will trip and you will have NO amps available so why say it.

A newbie hears he has two 120 legs and thinks he can not get hert with 240. WRONG ANSWER. The newbie comes on these threads and says "It's not 240 is two 120 legs". It is very much 240 volts @ 50 amps. As long as I live and breath I will call out the 100 amps available BS.

[BeachRetreat]

Originally Posted by Cavie

jimD You almost have it right. 240 volts is delivered to 50 amp RV's. MOST of the RV panels (except for very high end MH) are made in such a way that you can not plug in a 2 pole breaker except for the MAIN. Therefore you can not access 240 volts. 240 volts is across L1 and L2 but that's it. No 240 access with 2 pole breakers.

It's not that the different legs are run thruout your house. It's 120 on Buss bar A (L1) and 120 on Buss bar B (L2). If your house has a 200 amp service. You say "I have a 200 amp service" correct? Guess what? It's just like the RV. 120 down each leg. BUT your hose panel is made just like the High End MH. You can access 240 volts with a 2 pole breakers.

You will never hear an electrician say 100 amps available. On the technical side it is correct BUT what nobody understands is IF one leg goes over 50 amps the main will trip and you will have NO amps available so why say it.

A newbie hears he has two 120 legs and thinks he can not get hert with 240. WRONG ANSWER. The newbie comes on these threads and says "It's not 240 is two 120 legs". It is very much 240 volts @ 50 amps. As long as I live and breath I will call out the 100 amps available BS.

I would be curious is you would agree that if the loads were perfectly balanced, an RV with 50 Amp service could pull a total of 80 amps if 120V power?

[Cavie]

Originally Posted by BeachRetreat

I would be curious is you would agree that if the loads were perfectly balanced, an RV with 50 Amp service could pull a total of 80 amps if 120V power?

YES as long as no leg went over 50 amps. 50/30, 40/40, 45/35 OK. 55/30 NO.

[RetiredOne]

Originally Posted by Vicr

You don't have 100 amps available on a 50 amp service, period. There is a double pole breaker because you have two opposing phases of electricity. Why do you argue with electricians?

See the next quote:

Originally Posted by BeachRetreat

I would be curious is you would agree that if the loads were perfectly balanced, an RV with 50 Amp service could pull a total of 80 amps if 120V power?

As long as one leg doesn't exceed 50 amps, with balanced circuits, you could pull 45 amps (of 120 volts) on each leg. It's only if one leg exceeds 50 amps will the double pole 50 breaker trip.