Reply
 
Thread Tools Display Modes
Old 05-31-2020, 09:14 AM   #1
Member
 
Join Date: Sep 2014
Location: North of I-10 & South of I-94, but East of I-5 & West of I-95
Posts: 94
Dogbone Adapter

So here's what I don't get...someone help me out here.
When I plug my 50amp to 115 volt Dogbone adapter in. I have power to both 50 amp lines in the camper.
For example, Hot line A has the TV on it. Hot Line B as the charger. With both 50 amp main breakers on. I have power to the TV and charger.
I was under the impression, that these adapters were only powering 1 Hot Line, not both, because grid power is 180 degrees out of phase.
So Im confused...
__________________

2nd House is offline   Reply With Quote
Old 05-31-2020, 09:54 AM   #2
Senior Member
 
bubbles's Avatar
 
Join Date: Dec 2012
Posts: 4,915
Not powering but using 1 line (the only line in your case) paralleling to both lines within the adapter for your 50A plug to your unit. That's the purpose of an adapter. Your total amperage use will be limited to the input source though be it 20A/30A or whatever.
__________________

bubbles is offline   Reply With Quote
Old 05-31-2020, 10:09 AM   #3
Senior Member
 
Join Date: Oct 2015
Posts: 450
And it is not a problem in the rig because you don't have anything that takes 220V. If you did it would not work.
__________________
Dale & Karen
2015 Lacrosse 311RLS
2006 F-250 The 06-6.0
Dwilcox is offline   Reply With Quote
Old 05-31-2020, 10:40 AM   #4
Senior Member
 
SlowrideHD's Avatar
 
Join Date: Sep 2015
Location: North Alabama
Posts: 940
There is simply a jumper in the dogbone that jumpers leg 2 onto leg 1. So both legs of your indoor service panel are getting power, its just not originating from two different legs.
__________________

2016 F350 CC Dually Powerstroke 4x4
2014 Cedar Creek 34RLSA w/Level Up
2007 HD Ultra Classic 103
SlowrideHD is offline   Reply With Quote
Old 05-31-2020, 12:29 PM   #5
Member
 
Join Date: Sep 2014
Location: North of I-10 & South of I-94, but East of I-5 & West of I-95
Posts: 94
So the jumper inside I get, and being regulated by input voltage to both Hot Legs I understand. However, you're changing a split phase system to a single phase.
It'd be like taking a normal single phase inverter, and simply jumping over to the 2nd Hot Leg...if it were that easy, everyone would do it, instead of buying expensive split phase inverters. Or, instead of buying an expensive dual line generator, simply buy a single phase inverter and jumping the one Hot Leg to the second Hot Leg.
The 50 amp camper has two Hot Legs, just like a house. for a total of 100 amps useable. Those two Hot Legs have to be 180 degrees phased separation, just like a split phase Inverter. A simple jumber does not do this, so I'm not understanding it.
Thanks
2nd House is offline   Reply With Quote
Old 05-31-2020, 01:37 PM   #6
Senior Member
 
Join Date: Mar 2014
Posts: 2,051
The phase relationship in the feed doesn't matter because everything in your RV is single phase. 220V equipment requires split phases, 110V equipment does not. So even though in a normal configuration one phase goes to one side of your breaker box, and the other phase goes to the other side, the relationship between the phases doesn't matter.

Should you install a 220V dryer or A/c, then you have a very different story.

Fred W
pgandw is offline   Reply With Quote
Old 05-31-2020, 01:38 PM   #7
Senior Member
 
bubbles's Avatar
 
Join Date: Dec 2012
Posts: 4,915
Quote:
Originally Posted by 2nd House View Post
The 50 amp camper has two Hot Legs, just like a house. for a total of 100 amps useable. Those two Hot Legs have to be 180 degrees phased separation, just like a split phase Inverter. A simple jumber does not do this, so I'm not understanding it.
Thanks
Only different phases if one wants 50A per phase and that is what is provided at a typical RV power pedestal. Some pedestals do not have 50A available but does have 30A available and that is where a 50A RV would use an adapter. That adapter only can provide a single phase to the RV 50A plug and therefore only 30A total (for both RV busses) is available. It's probably worth noting that onboard generators are only single phase (interconnect is the same as using an adaptor) but available Amps vary with the different generators. The split phase does provide 240V at 100A but there is nothing in your RV that requires 240V (split phase not required) so an adapter will power your needs up to whatever power source your adapter is connected to (30A or less). Other than that it's magic.
bubbles is offline   Reply With Quote
Old 05-31-2020, 02:05 PM   #8
Just as confused as you
 
Scrapper's Avatar
 
Join Date: Aug 2013
Location: Wilderness CG, WI
Posts: 3,959
Quote:
Originally Posted by 2nd House View Post
So the jumper inside I get, and being regulated by input voltage to both Hot Legs I understand. However, you're changing a split phase system to a single phase.
It'd be like taking a normal single phase inverter, and simply jumping over to the 2nd Hot Leg...if it were that easy, everyone would do it, instead of buying expensive split phase inverters. Or, instead of buying an expensive dual line generator, simply buy a single phase inverter and jumping the one Hot Leg to the second Hot Leg.
The 50 amp camper has two Hot Legs, just like a house. for a total of 100 amps useable. Those two Hot Legs have to be 180 degrees phased separation, just like a split phase Inverter. A simple jumber does not do this, so I'm not understanding it.
Thanks

Though you are right about changing from a split-phase system to a single phase you have to realize the RV does not know that. Anything connected to electricity is dumb that way as long as it doesn't need 220 volts or 3-phase.

This 30A to 50A dogbone drawing may help you understand. Black is 120v hot, notice the jumper connected to both hot legs of the 50A outlet. Grey is neutral, green is ground. A 15/20A to 50A dogbone will work the same.
Attached Thumbnails
Click image for larger version

Name:	30-50ampDogbone.jpg
Views:	15
Size:	40.3 KB
ID:	230307  
__________________
Richard & Jill
2014 Flagstaff 832IKBS Classic Super Lite
2018 Silverado 1500 Crew Cab Z71 4WD All Star Edition
Camping since 1989, seasonal since 2000
Car Shredder Op/Tech, Scrap Metal Recycling - retired
The Faster I Go, The Behinder I Get.
Scrapper is offline   Reply With Quote
Old 06-01-2020, 08:40 AM   #9
Senior Member
 
SlowrideHD's Avatar
 
Join Date: Sep 2015
Location: North Alabama
Posts: 940
Quote:
Originally Posted by 2nd House View Post
The 50 amp camper has two Hot Legs, just like a house. for a total of 100 amps useable. Those two Hot Legs have to be 180 degrees phased separation, just like a split phase Inverter. A simple jumber does not do this, so I'm not understanding it.
Thanks
I don't know how you got the idea that the two 50 amp legs had to be on different phases. They don't, because they never work together, unless you have a 240 volt appliance somewhere. The two separate 50 amp legs in a 50 amp camper may just as well be two completely separate vehicles.
__________________

2016 F350 CC Dually Powerstroke 4x4
2014 Cedar Creek 34RLSA w/Level Up
2007 HD Ultra Classic 103
SlowrideHD is offline   Reply With Quote
Old 06-01-2020, 08:47 AM   #10
Site Team
 
Flybob's Avatar
 
Join Date: Oct 2014
Posts: 11,428
Quote:
Originally Posted by SlowrideHD View Post
I don't know how you got the idea that the two 50 amp legs had to be on different phases. They don't, because they never work together, unless you have a 240 volt appliance somewhere. The two separate 50 amp legs in a 50 amp camper may just as well be two completely separate vehicles.
Actually not completely separate as they share a common neutral
__________________

2015 Freedom Express 248RBS
TV 2015 Silverado HD2500 Duramax
TST Tire Monitors
Honda 2000I + Companion
2 100W solar panels
Flybob is offline   Reply With Quote
Old 06-01-2020, 02:02 PM   #11
Just as confused as you
 
Scrapper's Avatar
 
Join Date: Aug 2013
Location: Wilderness CG, WI
Posts: 3,959
Quote:
Originally Posted by Flybob View Post
Actually not completely separate as they share a common neutral
This brings to question for those with more knowledge than I. If the two 50a legs are supplied by the same phase will the common neutral cause a problem? I'm thinking that with the difference on the neutral not being 180* out of phase it might be like a short. I know how it works for 220 volts in a household setting but we are talking RV's here. Now I'm probably wrong but curious minds need to know.
__________________
Richard & Jill
2014 Flagstaff 832IKBS Classic Super Lite
2018 Silverado 1500 Crew Cab Z71 4WD All Star Edition
Camping since 1989, seasonal since 2000
Car Shredder Op/Tech, Scrap Metal Recycling - retired
The Faster I Go, The Behinder I Get.
Scrapper is offline   Reply With Quote
Old 06-01-2020, 08:04 PM   #12
Senior Member
 
Join Date: Aug 2019
Location: Central NJ
Posts: 216
In the typical situation when the 2 phases are 180 out of sync, the common neutral would only carry the difference in the current. So if leg 1 was drawing 20 amps, and leg 2 was drawing 10 amps, the neutral would draw 20-10= 10 amps.

When you use a dogbone that ties the two legs together, then the neutral carries all the current. Typically this is not a problem because you are tying the legs to a much lower powered source, say a household 20amp circuit. So the neutral could never carry more than the 20 amps the circuit could provide, well below the 50 amps its rated for.

Now lets say in some odd setup you tie two 30 services to the trailer, but they are both in phase. You can get a total of 60 amps going down the neutral in this case and over load it. I can't imagine how you would get two in phase 30 amp feeds.

Jim M.
__________________
2020 Flagstaff Super Lite 26RBWS
Former: 2017 Rockwood MiniLite 2104S
2015 Silverado 2500HD 6.0L Gas
jimmarako is offline   Reply With Quote
Old 06-01-2020, 08:08 PM   #13
Site Team
 
wmtire's Avatar
 
Join Date: Nov 2010
Location: Northeast Louisiana
Posts: 23,391
See if this previous discussion on this can be of help;. I just referenced it in another thread. It has diagrams.



https://www.forestriverforums.com/fo...ml#post1447703


and this one:


https://www.rvtechmag.com/electrical/chapter3.php
__________________
2011 Flagstaff 831 RLBSS


I've reported my DNA missing just in case it's found somewhere bad.
wmtire is offline   Reply With Quote
Old 06-01-2020, 08:11 PM   #14
Member
 
Join Date: Sep 2014
Location: North of I-10 & South of I-94, but East of I-5 & West of I-95
Posts: 94
Quote:
Originally Posted by pgandw View Post
The phase relationship in the feed doesn't matter because everything in your RV is single phase. 220V equipment requires split phases, 110V equipment does not. So even though in a normal configuration one phase goes to one side of your breaker box, and the other phase goes to the other side, the relationship between the phases doesn't matter.

Should you install a 220V dryer or A/c, then you have a very different story.

Fred W
Understood, it also makes a lot of sense not spending a lot of money on a spit phase inverter, as nothing in my camper is 220 volt. Seems purchasing an 6KW inverter, and splitting at the transfer switch to both Hot Legs to the camper fuse box, would supply more than enough power to run everything (except AC due to draining the batteries quickly). So why would people buy a spit phase inverter, if no 220 volt appliances are present...except it makes for a much cleaner install.
2nd House is offline   Reply With Quote
Old 06-01-2020, 08:13 PM   #15
Member
 
Join Date: Sep 2014
Location: North of I-10 & South of I-94, but East of I-5 & West of I-95
Posts: 94
Quote:
Originally Posted by jimmarako View Post
In the typical situation when the 2 phases are 180 out of sync, the common neutral would only carry the difference in the current. So if leg 1 was drawing 20 amps, and leg 2 was drawing 10 amps, the neutral would draw 20-10= 10 amps.

When you use a dogbone that ties the two legs together, then the neutral carries all the current. Typically this is not a problem because you are tying the legs to a much lower powered source, say a household 20amp circuit. So the neutral could never carry more than the 20 amps the circuit could provide, well below the 50 amps its rated for.

Now lets say in some odd setup you tie two 30 services to the trailer, but they are both in phase. You can get a total of 60 amps going down the neutral in this case and over load it. I can't imagine how you would get two in phase 30 amp feeds.

Jim M.
Thank you...the neutral example solves the problem
__________________

2nd House is offline   Reply With Quote
Reply

Thread Tools
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



» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Forest River, Inc. or any of its affiliates. This is an independent, unofficial site.



All times are GMT -5. The time now is 03:12 AM.


×