RV News RVBusiness 2021 Top 10 RVs of the Year, plus 56 additional debuts and must-see units → ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > MOTORHOME FORUMS > MH-General Discussions & Problems
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 11-15-2020, 09:36 PM   #1
Senior Member
 
Join Date: Mar 2019
Posts: 312
50amp to 30amp=?

When using a 50amp dog bone adapter reduced to 30amps on a CG pedestal, what is the output? Iíve read 30 amps. Isnít each of the double pole 50 amp breakers rated 50 amps and will trip at 45 amps continuously on each leg. So the math doesnít make sense to me if wiring rated for 30 amps will handle the heat? Can someone set me straight?
Johnynorthla is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 11-15-2020, 10:01 PM   #2
Senior Member
 
Join Date: Nov 2015
Posts: 14,504
If RV is 30A and using a 50A to 30A Adapter...
Adapter only uses 1 HOT leg and the RV Main 30A CB would trip if amp draw exceeded the CB

The Adapter/RV Power Cord only has the protection of the 50A CB at the CG Power Pedestal (along with any devices installed between Power cord and RV Main Panel ---ATS/EMS etc)
BUT the RV Main 30A breaker limits the amp draw thru the one HOT leg...unless adapter/power cord etc have a short. Then the 50A CB at CG pedestal would trip all power to RV



=========================================

30A to 50 Adapter Only has 1 Hot from the 30A Receptacle

So if using on a 50A RV......
The 30A adapter connects both 50A Hots within the adapter
Therefore each Hot would have 15A capability...total of 30A
*or any combination that totals 30A
If you exceed the 30A Total...then CG Power Pedestal 30A Breaker would trip
The dual 50A CBs in the RV AC Panel would NOT
*Individual branch CBs could trip if the Amp Rating (15/20 etc) was exceeded

30A to 50A Adapter
__________________
Is it time for YOUR Medication or Mine?
Dodge 3500 w/Tractor Motor & NUWA 5vr
US NAVY---USS Decatur DDG-31
Old-Biscuit is online now   Reply With Quote
Old 11-16-2020, 05:28 AM   #3
Senior Member
 
Join Date: Mar 2019
Posts: 312
Quote:
Originally Posted by Old-Biscuit View Post
If RV is 30A and using a 50A to 30A Adapter...
Adapter only uses 1 HOT leg and the RV Main 30A CB would trip if amp draw exceeded the CB

The Adapter/RV Power Cord only has the protection of the 50A CB at the CG Power Pedestal (along with any devices installed between Power cord and RV Main Panel ---ATS/EMS etc)
BUT the RV Main 30A breaker limits the amp draw thru the one HOT leg...unless adapter/power cord etc have a short. Then the 50A CB at CG pedestal would trip all power to RV



=========================================

30A to 50 Adapter Only has 1 Hot from the 30A Receptacle

So if using on a 50A RV......
The 30A adapter connects both 50A Hots within the adapter
Therefore each Hot would have 15A capability...total of 30A
*or any combination that totals 30A
If you exceed the 30A Total...then CG Power Pedestal 30A Breaker would trip
The dual 50A CBs in the RV AC Panel would NOT
*Individual branch CBs could trip if the Amp Rating (15/20 etc) was exceeded

30A to 50A Adapter
Ok, I understand that my 30 amp RV main panel breaker will trip, that saves all the devices and wires after my main panel, but isnít my power cord from the CG pedestal and all the 10 GA wiring to my ATS and main panel rated for 30 amps? These would be plugged into a double pole 50 amp breaker using a single pole 50 amp breaker segregated by the dog bone adapter. That still doesnít make sense to me?
Johnynorthla is offline   Reply With Quote
Old 11-16-2020, 05:33 AM   #4
Senior Member
 
Join Date: Mar 2019
Posts: 312
Im thinking of always using the pedestals 50 amp with a 30 amp dog bone to my RV to free up the pedestals 30 amp, so I can use a 30 amp to 15 amp dog bone to run Auxiliary outlets. But after my ATS fried I’m looking at every draw to prevent any future problems!
Johnynorthla is offline   Reply With Quote
Old 11-16-2020, 05:51 AM   #5
Senior Member
 
Winnebago Owners Club
Join Date: Aug 2019
Location: Meshoppen, PA
Posts: 889
Quote:
Originally Posted by Johnynorthla View Post
Ok, I understand that my 30 amp RV main panel breaker will trip, that saves all the devices and wires after my main panel, but isnít my power cord from the CG pedestal and all the 10 GA wiring to my ATS and main panel rated for 30 amps? These would be plugged into a double pole 50 amp breaker using a single pole 50 amp breaker segregated by the dog bone adapter. That still doesnít make sense to me?
Lost the pic from previous quote.. regardess.

you have a 10 g wire.. capabale of 30 amps TOTAL,, so when you adapt to a 50A RV feed from the 30A pedistal... that 30A of max power gets split to the both banks/sides of the RV 50A panel,,, so you can pull 30A all from one side or the other, or spit it 15/15, 20/10, all depends on your load use..

The confusing part is the RV 50A, as it has 2 legs of 120 power.. each has a 50A potential so for all purpose the 50A RV has potential of pulling 100A max.

The 30A single leg 30 only gives you ONE 30A that the adapter share over the 2 leg 50A plug..
sibe is offline   Reply With Quote
Old 11-16-2020, 05:53 AM   #6
Senior Member
 
Join Date: Jul 2014
Posts: 25,411
50 amps is only the potential draw amp from the outlet.
Its like Horsepower, you only use it if you floor the pedal.

So, to draw over 50 amp thru your ATS, you will need to clamp the wires together, for a dead short, before the RV breaker.

One more point, the electric code leaves a margin of safety. A 30 amp service will not burst into flames or melt components if it had to carry 50 amps.

Your concerned about using 50 amp outlet for your 30 amp RV, but your doing it to free up the 30 amp outlet to plug in 15 amp things.
You could leave the RV on 30 amps and get a 50 to 15 amp dogbone adaptor.
twinboat is offline   Reply With Quote
Old 11-16-2020, 06:07 AM   #7
Junior Member
 
Join Date: Oct 2020
Posts: 29
Quote:
Originally Posted by twinboat View Post
50 amps is only the potential draw amp from the outlet.
Its like Horsepower, you only use it if you floor the pedal.
Similar to what I was going to say. The amperage is going to go up and down depending on what you are using. 30 vs 50 it how much you can take, hence a breaker to stop you from attempting to take too much and wiring to handle that amount. I heard it compared to water.
"VOLTAGE is like the pressure that pushes water through the hose. It is measured in volts (V).
CURRENT is like the diameter of the hose. The wider it is, the more water will flow through. It is measured in amps (I or A)." --
From https://www.freeingenergy.com/unders...flow%20through.
__________________
Steve
1999 Lazy Daze 26.5' Mid Bath (1999 Ford E450 SuperDuty Chassis)
Sgare is offline   Reply With Quote
Old 11-16-2020, 11:34 AM   #8
Senior Member
 
Winnebago Owners Club
Join Date: Aug 2019
Location: Meshoppen, PA
Posts: 889
Quote:
Originally Posted by Johnynorthla View Post
When using a 50amp dog bone adapter reduced to 30amps on a CG pedestal, what is the output? Iíve read 30 amps. Isnít each of the double pole 50 amp breakers rated 50 amps and will trip at 45 amps continuously on each leg. So the math doesnít make sense to me if wiring rated for 30 amps will handle the heat? Can someone set me straight?
Is this more of what you are asking, a 30 amp RV plug into a 50Amp pedistal..

you will pull atleast 30Amp off that led protected by your RV 30 amp main,, that adapter can have a potential of 50A off one leg to trip the pedistil breaker,, .
Attached Thumbnails
Click image for larger version

Name:	50-30ampDogbone.jpg
Views:	5
Size:	39.7 KB
ID:	308250  
sibe is offline   Reply With Quote
Old 11-17-2020, 08:00 AM   #9
Senior Member
 
Join Date: Mar 2019
Posts: 312
Wow! Lots of great info and advice, thanks everyone. I understand now.

I installed 2 auxiliary outlets, one in to my bathroom, for wife’s hairdryer, another in the kitchen, for coffee, toaster etc.. Both of these outlets are each plugged in to the CG pedestal. One in the 15 amp, the other in the 50amp, (reduced to 15 amp with adapter)

My intentions is to not trip the breaker when AC is on. But of course it’s going to be a chilly week every morning hear on the Gulf coast. But I’ll take it!
Johnynorthla is offline   Reply With Quote
Old 11-26-2020, 11:08 AM   #10
Senior Member
 
Gulf Streamers Club
Ford Super Duty Owner
Join Date: Aug 2015
Location: Memphis, TN
Posts: 1,607
If talking 50a coach and 30a receptacle, it connects BOTH L1/L2 to L1 and LIMIT is 3600-watts (vs 12,000-watts on 50a w/ dual 120v). 50a is DUAL 120VAC CIRCUITS @50a/each
__________________
(TerryH.) 2000-GS Conquest Limited 6266 Class-C 99-E450SD V10
THenne1713 is offline   Reply With Quote
Old 11-26-2020, 12:23 PM   #11
Senior Member
 
Hooligan's Avatar
 
Freightliner Owners Club
Join Date: Apr 2002
Location: Pensacola
Posts: 2,695
Quote:
Originally Posted by THenne1713 View Post
If talking 50a coach and 30a receptacle, it connects BOTH L1/L2 to L1 and LIMIT is 3600-watts (vs 12,000-watts on 50a w/ dual 120v). 50a is DUAL 120VAC CIRCUITS @50a/each
I believe the question is connecting a 50 amp pedestal to 30 amp power cord. Sibe (post# 8) is on the right track. Only one leg of the 50amp is connected to the only hot on the 30 amp cord.
__________________
Hooligan, Pensacola, Fl -U.S. Coast Guard 1956-1985
2016 Thor Siesta Sprinter 24ST diesel -1972 Moto Guzzi
2008 Suzuki Grand Vitara TOAD
Hooligan is offline   Reply With Quote
Old 11-26-2020, 01:18 PM   #12
Moderator Emeritus
 
Gary RVRoamer's Avatar


 
Join Date: Jan 2000
Location: Silver Springs, FL. USA
Posts: 23,567
It's simple enough. You can't get more than 30A from a 30A outlet no matter what kind of power cord you plug in. 30 is all there is. The standard 50/30 adapter connects both 50A hot wires to the single 30A wire at the source, but the combined amps on the two 50A wires cannot exceed 30A.
__________________
Gary Brinck
Former owner of 2004 American Tradition and several other RVs
Home is in the Ocala Nat'l Forest near Ocala, FL
Summers in Black Mountain, NC
Gary RVRoamer is offline   Reply With Quote
Old 11-26-2020, 10:09 PM   #13
Senior Member
 
Join Date: Apr 2015
Location: Rogers, AR
Posts: 1,373
Quote:
Originally Posted by Johnynorthla View Post
Wow! Lots of great info and advice, thanks everyone. I understand now.

I installed 2 auxiliary outlets, one in to my bathroom, for wife’s hairdryer, another in the kitchen, for coffee, toaster etc.. Both of these outlets are each plugged in to the CG pedestal. One in the 15 amp, the other in the 50amp, (reduced to 15 amp with adapter)

My intentions is to not trip the breaker when AC is on. But of course it’s going to be a chilly week every morning hear on the Gulf coast. But I’ll take it!
You never explained what you have for a coach (power), or what you have/want to do until you got to post #9 above. You need to start your post with telling us what you have and are doing.

I assume you have a 30A wire from your coach to the pedestal, and when you run the A/C plus a couple other things, it will trip the 30A breaker at the pedestal, or coach. To prevent this happening, you put in another plug for the coffee pot (with the proper gage wire ? ) and ran this wire directly to the 15A plug on the pedestal, that's OK, so the coffee pot won't affect the power needed to run the A/C.

Your second statement is dangerous as HE!!. The second outlet you installed (15A outlet ?) you ran directly to the 50A plug (did you use wire that will carry 50A of power ?) and plugged it in with the use of plug adaptors to take a 50A power plug down to 15A cord? Now you are feeding your wife's hair drier with a direct 50A line. FIRE AND DEATH MAY BE RIGHT AROUND THE CORNER MY FRIEND. And that's no joke. You never said anything about putting in a 15A circuit breaker in the hair dryer line. Is this what you really did?

If you don't understand power and voltage, you shouldn't be connecting any electrical lines.

If this isn't what you really did, I apologize, please explain what you really did.
__________________
2019 Fleetwood Discovery LXE 40M w/2012 CRV toad
alank is offline   Reply With Quote
Old 11-27-2020, 09:16 PM   #14
Senior Member
 
Join Date: Jan 2009
Posts: 2,744
Quote:
Originally Posted by alank View Post
You never explained what you have for a coach (power), or what you have/want to do until you got to post #9 above. You need to start your post with telling us what you have and are doing.

I assume you have a 30A wire from your coach to the pedestal, and when you run the A/C plus a couple other things, it will trip the 30A breaker at the pedestal, or coach. To prevent this happening, you put in another plug for the coffee pot (with the proper gage wire ? ) and ran this wire directly to the 15A plug on the pedestal, that's OK, so the coffee pot won't affect the power needed to run the A/C.

Your second statement is dangerous as HE!!. The second outlet you installed (15A outlet ?) you ran directly to the 50A plug (did you use wire that will carry 50A of power ?) and plugged it in with the use of plug adaptors to take a 50A power plug down to 15A cord? Now you are feeding your wife's hair drier with a direct 50A line. FIRE AND DEATH MAY BE RIGHT AROUND THE CORNER MY FRIEND. And that's no joke. You never said anything about putting in a 15A circuit breaker in the hair dryer line. Is this what you really did?

If you don't understand power and voltage, you shouldn't be connecting any electrical lines.

If this isn't what you really did, I apologize, please explain what you really did.
Not if the OP used something like this.
__________________
03 Itasca Sunova, Workhorse P32 with the 8.1 and 4L85-E
Mudfrog is online now   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
50amp RV with 30amp cord and 50amp adapter Jasindude1 MH-General Discussions & Problems 77 06-04-2020 02:10 AM
Question about reducing a 50amp down to a 30amp cord for 30amp service Tony4qts Class C Motorhome Discussions 22 04-13-2019 04:15 PM
50amp to 30amp to 50amp SwampTrash RV Systems & Appliances 4 05-09-2010 09:23 AM
30amp or 50amp?? Greybeard Winnebago Industries Owner's Forum 12 07-15-2008 09:57 AM
Is 50amp better than 30amp? Tom from Tucson RV Systems & Appliances 13 10-21-2006 03:58 PM


All times are GMT -6. The time now is 05:48 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.