Go Back   iRV2 Forums > iRV2.com COMMUNITY FORUMS > iRV2.com General Discussion
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 03-14-2009, 12:32 PM   #29
Senior Member
 
Join Date: Mar 2008
Posts: 222
You keep hearing you should have a Surge protector on board.. Do some coaches have this built into to system? or is it something you should add?? My coach is a 2008 4354 DSDP...Vacman
__________________

__________________
2008 Dutch Star 4354
Full Slide, Bath & 1/2
2008 Jeep 4 Dr Unlimited tow
VACMAN 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 03-14-2009, 01:50 PM   #30
Senior Member
 
Join Date: Nov 2006
Location: Grayson, GA
Posts: 862
Quote:
Originally Posted by VACMAN View Post
I think I get it now..L1-N-L2-Green earth G will work to plug in the RV...But L1-earth G-L2 will run the welder but screw up coach.. Simply by adding the N makes the difference..Is that the short of it?? VACMAN
Vacman

Norm had it correct when he replied above ---- L1 + netural makes up one 120 volt circuit and L2 + ground makes up the other 120 volt circuit. L1 comes from one side of the bus bar in a breaker box and L2 comes from the other bus bar in a breaker box. You do not want both L1 and L2 coming from the same bus bar. And as he said and you did finally, don't use the welder plug in or any other regular 220 plug. They are L1 + N + L2 and the ground is separate --- different type of configuration and will blow the items in the MH. The link that I posted in an earlier post actually has the wiring diagram coming from the meter base on your house which shows the separation of L1 and L2 (coming from different legs).
__________________

__________________
Dave and Karen -- '02 Ultimate Advantage 36 C, 350 HP Cummins, Allison 3060 Tranny
'07 Ford Escort, Brake Master 4160, '13 Ford Edge, InvisiBrake
David K is offline   Reply With Quote
Old 03-14-2009, 01:59 PM   #31
Senior Member
 
Join Date: Nov 2006
Location: Grayson, GA
Posts: 862
Quote:
Originally Posted by VACMAN View Post
You keep hearing you should have a Surge protector on board.. Do some coaches have this built into to system? or is it something you should add?? My coach is a 2008 4354 DSDP...Vacman

Vacman

What most people are referring to is a surge protector that is between the shore power source and your MH. I have a hard wired SurgeGuard surge protector wired in my MH. The shore cord plugs into the normal campground supply source then runs through the SurgeGuard and then into the normal plug in for the MH. When you initially plug in, the SurgeGuard checks the incoming current for under/over voltage, polarity, etc. It waits for a little over two minutes before it will allow current to pass on through to the MH -- this is done in case you have had a shut down with the air conditioning running -- it allows the head pressure on the air conditioning to go down before restarting it. In cases of over/under current conditions the SurgeGuard will shut down the inflow of current. There are other models out there that some other people use and some of them are hard wired as well as being "portable" -- ie, used at the plug in source (power pole). I went the hard wired way so the SurgeGuard is inside of the power area of my MH and not subject to thieft.

If you want to see a picture of the hard wired SurgeGuard, go to the top of the forum page and select photos, when there, select search and do a search of the user name of dknig288 ---- that is my photo post name. You will find a picture of my hard wired SurgeGuard in that area.

In my opinion, I would not go anywhere without surge protection of some sort -- especially with what the cost of the components in the MHs being what they are.

I am sure that others will "chime" in about what they use.
__________________
Dave and Karen -- '02 Ultimate Advantage 36 C, 350 HP Cummins, Allison 3060 Tranny
'07 Ford Escort, Brake Master 4160, '13 Ford Edge, InvisiBrake
David K is offline   Reply With Quote
Old 03-14-2009, 10:09 PM   #32
Senior Member
 
Jocat54's Avatar
 
Monaco Owners Club
Join Date: Oct 2008
Location: Leakey, Tx (Texas Hill Country)
Posts: 109
Quote:
Originally Posted by Route 66 View Post
I believe a 240 volt 50 amp welder circuit is a 3 wire circuit with one 50 amp breaker and is 240 volts only.

RV 50 amp service is a 4 wire circuit with two 50 amp breakers and can be used a 240 volts 50 amps across L1 and L2, or 2 120 volt 50 amp circuits, L1 to N and L2 to N.

RV 50 amp service is the same as an electric range service.

The link previously mentioned above explains it all, with pictures.
All 240v service is two breakers, maybe tied together with a common trip bar, but you have to have 2 120v "legs" to get 240v.
__________________
John & Kathy & Gizmo (Maltipoo)
1999 38ft Monaco Diplomat DP
Jocat54 is offline   Reply With Quote
Old 03-14-2009, 10:24 PM   #33
Moderator Emeritus
 
Gary RVRoamer's Avatar


 
Join Date: Jan 2000
Location: Silver Springs, FL. USA
Posts: 18,066
I put a override switch on my EMS so I can force it into generator mode when I hook up the cheater box to two 120v sources that are in phase (aka "on the same leg"). That way I get to use the full power of whatever I have available. It's not too difficult to do with the Intellitec EMS - basically have to switch a 12v source to J2 pin 2 so that it thinks the genset is running.
__________________
Gary Brinck
Former owner of 2004 American Tradition
Home is in the Ocala Nat'l Forest near Ocala, FL
Summers in Black Mountain, NC
Gary RVRoamer is offline   Reply With Quote
Old 03-15-2009, 12:28 AM   #34
Senior Member
 
porscheracer's Avatar
 
Join Date: Apr 2008
Location: Back at the stix'n'brix - East End, AR.
Posts: 553
Thanks, Gary. I'll have to figure out how to do that "cheat" on mine.
__________________
Norm & Janet

FMCA; WIT; FCOA; Good Sam; Passport
porscheracer is offline   Reply With Quote
Old 03-15-2009, 06:43 AM   #35
Community Moderator
 
RV Wizard's Avatar


 
Country Coach Owners Club
Appalachian Campers
Gulf Streamers Club
Join Date: Mar 2000
Location: Chattanooga, Tn.
Posts: 12,062
Gary has discribed what I was stating about making your EMS think the generator is in use.
__________________
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7
RV Wizard is offline   Reply With Quote
Old 03-15-2009, 04:29 PM   #36
Senior Member
 
RVDude's Avatar
 
Join Date: Sep 2006
Posts: 1,339
In several parts of the country N and G are bonded - that is they are exactly the same coming off the exact same main panel bus bar.. Hence an L1-N-L2/G and L1-G-L2/N are *electrically* identical but not code compatible if the bare wire is used as the N.

This gives L1-L2 = 240VAC, L1-N or L2-N = 120VAC which is a typical 50A RV plug which is also a typical stove plug (3 vertical blades + 1 round). This is a national code standard plug.

I also think that national code allows this style plug to be wired in either the 120V (i.e. L1 and L2 "in phase" that is off the same line bus such that L1-L2=0VAC) OR the 240V (L1 and L2 "out of phase" that is different bus L1-L2=240VAC) configuration INTERCHANGEABLY at the rated 50A capacity. Again, in the 120V configuration L1-L2=0VAC and of course L1-N and L2-N are both 120VAC.

I further think that 50A @ 240VAC = 2 * 50A @ 120VAC. So a single 50A 240VAC breaker (actually a double breaker) will provide the full 50A 120V on both L1 and L2 legs.

Again code allows this plug to be wired either in the 120V or 240V configuration. Hence either may be used as your 50A supply in any 50A camper. Every CG I have stayed in thus far has L1-L2=240VAC further suggests that EVERY 50A camper will accept L1-L2=240VAC OR the other standard of L1-L2=0VAC (2 identical phase 120VAC legs) UNLESS you have a 240V appliance in your rig (then you need the 240V service but will do NO damage plugging into a 120V service - the appliance just won't work). The plug style dictates the standard wiring and amperage. If the receptacle is up to code and your plug fits you can use it.

BTW -
1) A 50A 240V breaker is actually a double breaker spanning both panel buses.
2) Run length has a significant affect on wire size.
3) The amperage running down N in a 240VAC setup is the difference in the current being pulled by the L1/L2 legs. Hence if you are pulling a full 50A off BOTH L1 AND L2 the current on the N is 0A. Also if say L1 is at 50A and L2 is at 0A then N will show 50A. Of course we always hope the G always has 0A or we have a dangerous ground fault - current is bleeding someplace.

4) And MOST importantly a L1-L2=240VAC setup will require MUCH smaller wire size than the L1-L2=0VAC (120VAC only) setup.

A final thought is that I believe the default position for your xfer switch is shore feed, hence, your xfer switch will connect by default to whatever shore power (be it "cheated" that is 120VAC config or not which is the 240VAC config) unless there is power from the genset feed to trigger the xfer switch over to that feed side.

Comments????????
__________________
2007 and 7/8ths Newmar Essex 4502
RVDude is offline   Reply With Quote
Old 03-19-2009, 08:22 AM   #37
Moderator Emeritus
 
Gary RVRoamer's Avatar


 
Join Date: Jan 2000
Location: Silver Springs, FL. USA
Posts: 18,066
Quote:
Comments????????
RVDude: Can't see anything wrong with what you said.
__________________
Gary Brinck
Former owner of 2004 American Tradition
Home is in the Ocala Nat'l Forest near Ocala, FL
Summers in Black Mountain, NC
Gary RVRoamer is offline   Reply With Quote
Old 03-19-2009, 08:46 AM   #38
Moderator Emeritus
 
RustyJC's Avatar


 
Texas Boomers Club
Join Date: Jul 2000
Location: Cypress, Texas USA
Posts: 8,854
Yes, there's a problem with L1 and L2 being in phase in a 50 amp outlet when applied to 120/240VAC RV service. Neutral leg currents are additive, so if L1 is carrying 50 amps and L2 is carrying 40 amps, then the neutral leg current will be 50 + 40 = 90 amps if the hot legs are in phase. Theoretically, the neutral leg could be exposed to 100 amps if both hot legs were carrying 50 amps. Thus, if L1 and L2 are in phase, the neutral leg in a 120/240VAC RV service application can be easily overloaded since the shore power cord conductor is sized for 50 amps, just like the hot legs - this can result in melted neutral conductors and even electrical fires. That's why this is a definite no-no and campground recepticles should be checked to ensure that L1 to L2 = 240VAC before hooking up!

If the hot legs are out of phase by 180* as they would be on a correct 120/240VAC RV service (i.e., the service is being fed by the output of a center-tapped transformer), then the neutral leg current would be 50 + (-40) = 10 amps in our example and could never be over 50 amps (50 + (-0) = 50 amps).

Although mentioned in the post above, this potentially dangerous problem is worthy of a standalone caution.

Rusty
__________________
2016 Ram Longhorn 3500 Dually 4x4 CCLB, 385/900 Cummins, Aisin AS69RC, 4.10
2014.5 DRV Mobile Suites 38RSSA #6972
Come join us on a TEXAS BOOMERS rally!
RustyJC is offline   Reply With Quote
Old 03-19-2009, 09:08 AM   #39
Senior Member
 
RVDude's Avatar
 
Join Date: Sep 2006
Posts: 1,339
Rusty further emphasizes the 120v vs 240v wiring difference for the std RV (or stove) recepticals. All RVs will accept either config. If the voltage across L1-L2=0v then you have a 120v setup (in phase=same main bus tap off) where the wiring (reqd by code) better be able to handle 100A down the N. In a L1-L2=240v setup you have a 240v setup (180 out oof phase different main bus tapoff) the wiring will be much smaller. Mostly 240v pedestals out there for this very reason.
__________________
2007 and 7/8ths Newmar Essex 4502
RVDude is offline   Reply With Quote
Old 03-19-2009, 09:33 AM   #40
Senior Member
 
Join Date: Nov 2006
Location: Grayson, GA
Posts: 862
Rusty -- that is what I was trying to say but, you said it much better than I. The legs for the 120v need to be "out of phase" or from different sides of the breaker box -- not from the same bus bar as the most of the 240v in our houses are done. In the house, phase does not become a consideration as the appliance will use the "in phase" 120v and the neutral wire does not have to worry with the "additive" effect of the 220v -- it don't happen. I will have to remember the "in phase" and "180 degree out of phase" phrases for future reference -- this topic seems to "pop" up quite frequently.
__________________
Dave and Karen -- '02 Ultimate Advantage 36 C, 350 HP Cummins, Allison 3060 Tranny
'07 Ford Escort, Brake Master 4160, '13 Ford Edge, InvisiBrake
David K is offline   Reply With Quote
Old 03-20-2009, 09:31 AM   #41
Senior Member
 
porscheracer's Avatar
 
Join Date: Apr 2008
Location: Back at the stix'n'brix - East End, AR.
Posts: 553
As I stated before, many motorhomes will reject the L1 and L2 being on the same leg. If I hook up to that configuration, it senses and indicates 30A service. Probably a good thing, since I don't really want to be sending 100A back down the MH neutral.
__________________
Norm & Janet

FMCA; WIT; FCOA; Good Sam; Passport
porscheracer is offline   Reply With Quote
Old 03-20-2009, 03:20 PM   #42
Senior Member
 
Join Date: Oct 2003
Location: Fulltime- On the Road
Posts: 363
As stated when your RV EMS detects L1 and L2 are in-phase it configures your EMS as either a 30amp source or a 20 amp source (depending on switch settings). A 50amp to 30amp adapter ties L1 and L2 together and hence applies the same phase to each of the legs on the RV, and hence the EMS senses the source as 30 amps, or 20 amps.

Many RVs with 50 amp connections carry a 7.5KW generator. Assuming voltage and current are in phase (which is not true for inductive loads such as AC motors, but lets assume they are) then POWER = Voltage times Current. So a 7.5KW generator operating at 125Volts will provide approximately 60 amps of current. 7500 Watts = 125Volts times 60 amps (again, assuming voltage and current are in phase).

Rarely will the generator actually produce a full 60 amps, and hence, the neutral wire will not be overloaded in generator mode. However, "cheating" the EMS into thinking it is in generator mode, and pulling a full load on a power source that has both L1 and L2 in phase could overload the neutral. As previously stated.. you could potentially pull 100amps on the neutral if both legs L1 and L2 had 50 amps available and you were indeed pulling full capacity. Therefore you should not be creative by "faking " your EMS in generator mode unless you know for certain you are never pulling more than 50 amps Overloading the neutral could cause a fire anywhere along the neutral path all the way back to the main breaker panel where adequate sized neutral wires exist.

On the other hand, if you know the maximum loads your coach pulls on each leg then perchance you may be able to manage the risk. For instance, when I was on my own meter at one particular resort I used a cheater/adapter to get the "out of phase" L1/L2 power. My L1 source had a 30 amp breaker and my L2 source had a 20 amp breaker. The only time I would trip a breaker (the 20 amp) is when the Dryer, Hotwater Heater, and 2nd AC compressor were all running at the same time. So normally, I rarely pulled more than a total 50 amps as I recall only tripping a breaker once.

I also know under normal common sense conditions with my 7.5KW generator running I have never pulled more than 45 amps total. I'm sure I could add an electric heater while running the AC and pull more, but besides me, who would do that?? This means it would be highly unlikely that I would overload a neutral wire as my max draw would typically be only 45 amps. Your coach may be different and if you don't know you should not risk any fires or potential damage.
__________________

__________________
Roadking
2006 Country Coach Inspire. 51946
Roadking is offline   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
Wondering if I can use a 50 amp converter cord with my 30 amp service? luke_vardanian Travel Trailer Discussion 12 11-10-2008 04:34 AM
Will a 50 amp surge protector work with a 30 amp system CWIL 5th Wheel Discussion 5 08-21-2008 03:34 PM
30-amp dog-bone with 50-amp shore power jeeprubi RV Systems & Appliances 11 02-14-2008 04:10 AM
Vector 2-10-30 Amp, 80 Amp Start Battery Charger Logthumper Gear and Product Discussions 2 03-23-2007 04:24 AM
Replacing 20 amp electrical land line plug with 30 amp????? Ragman MH-General Discussions & Problems 6 07-21-2006 11:28 AM

» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 12:49 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.