Home » Public Forums » GMCnet » [GMCnet] Opinions or experience with a reverse Y adapter
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| Re: [GMCnet] Opinions or experience with a reverse Y adapter [message #94806 is a reply to message #94801] |
Fri, 06 August 2010 01:00   |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
Karma: 0
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Senior Member |
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| Byron Songer wrote on Thu, 05 August 2010 21:54 |
Anyone on here ever use an electric reverse Y adapter, otherwise known as a
50 amp adapter ideally combining 30 amp and 20 amp service to work with a 50
amp plug?
Good, bad or indifferent?
Byron Songer
1978 Royale by Coachmen
Louisville, KY
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Byron: They only work if the campground 20 amp outlet does NOT have a GFIC outlet or breaker, and they have been required by the National Electric Code for many years now. So, in most cases they are useless as the GFIC trips out.
Also, some campground outlet systems really only have a 30 amp breaker at the source, which supplies both the 30 and 20 amp outlets in the box you plug into, the 20 amp outlet having a sub breaker. So, trying to draw more than 30 amps total trips the supply to that specific pole at the site.
Mostly the thing you are asking about just won't work due to one of the above issues.
Rob Allen
former owner of '76 x-PB
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| Re: [GMCnet] Opinions or experience with a reverse Y adapter [message #94819 is a reply to message #94801] |
Fri, 06 August 2010 07:34 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| Byron Songer wrote on Fri, 06 August 2010 00:54 |
Anyone on here ever use an electric reverse Y adapter, otherwise known as a 50 amp adapter ideally combining 30 amp and 20 amp service to work with a 50 amp plug?
Good, bad or indifferent?
Byron Songer
1978 Royale by Coachmen
Louisville, KY
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Byron,
As Rob noted, the effort is fraught with difficulties.
I take it you mean a thing like
<http://www.campingworld.com/shopping/item/50-amp-rv-box-adapter/25774>
Scroll down and read the copy carefully.
The 50 amp (4-pin) that our coaches run is actually 50A - 240V - it uses 2 sides of a service just like a house does. A 30amp or less system is regularly 30A - 120V. As Rob also noted the 20Amp outlet, if it exists, is often pulled of the 30Amp breaker (there are code reasons for this that I will not go into).
How some ever. . .
If you run into a power post that has 2ea - 30Amp outlets and breakers, they are probably on opposite sides of the 3 wire system - so the hots are 240v to each other. If they are and you have all the appropriate plugs, you can make that behave like a 30A - 240V source.
Maybe Dan looked at the power posts when he was at DuQuoin and could tell you what the chance is that you can make this work there.
I have sometimes had to do such strange things in boatyards and marinas - and that with 5L-30 (twist lock) plugs.
Good Luck
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Opinions or experience with a reverse Y adapter [message #94821 is a reply to message #94819] |
Fri, 06 August 2010 07:43 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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I assembled one just like this. Using standard parts from your local big bock home store, it can be made for less than $20. Have not had to use it yet, but no reason why it would not work, both sides are isolated from each other, unless there is a GFI in the way.
My coach was (Avion) originally wired for 50A service, but P.O. re-wired it, and put both A/C's on the same circuit, along with everything else. Not a bright idea, but works. I suspect that a full load would trip all the breakers.
Tom Phipps,
GMC Ex-Avion
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: [GMCnet] Opinions or experience with a reverse Y adapter [message #94833 is a reply to message #94821] |
Fri, 06 August 2010 09:40 |
Arthur Mansfield
Messages: 290
Registered: April 2010
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I am at a small camp ground that has one row 50 amps and one row 30 amps. All sites are pull throughout and set up so that you can go through in either directions which means he has two sets of water, dump and power on both sides on each site. If you need 50 amp power on the 30 amp side he has boxes wired to hook up a 50 site if required. It is a nice basic park that is just off TN 64 (was on 64 until they made the 4 lane) call Powderhorn Camp ground (Mama J's Store) between Lawerenceburg and Pulaski Tn.
Art & Doris
76 EL
On Aug 6, 2010, at 6:43 AM, Thomas Phipps wrote:
>
>
> I assembled one just like this. Using standard parts from your local big bock home store, it can be made for less than $20. Have not had to use it yet, but no reason why it would not work, both sides are isolated from each other, unless there is a GFI in the way.
> My coach was (Avion) originally wired for 50A service, but P.O. re-wired it, and put both A/C's on the same circuit, along with everything else. Not a bright idea, but works. I suspect that a full load would trip all the breakers.
>
> Tom Phipps,
> GMC Ex-Avion
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
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| Re: [GMCnet] Opinions or experience with a reverse Y adapter [message #94838 is a reply to message #94821] |
Fri, 06 August 2010 11:02 |
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Allow me to provide a bit more clarification after stating that I'm not an
electrical engineer by any stretch of the imagination. I wire based on what
the picture shows.
Here's my understanding and please correct me if I'm wrong.
Whenever I'm in a campground and I see a 4-pin receptacle, I plug right in
and can run the AC, microwave, hair dryer, etc. When at an RV park with only
the crows feet receptacle, I put on the adapter and plug in to get power
that that seems to work correctly.
I was led to believe that the when plugging in (4-pin arrangement) that it
really breaks into two, separate circuits in the coach. Am I correct or
incorrect?
My father-in-law has an older home. It has no GFI receptacles to protect
humans (which is the primary design purpose). If I can plug into two,
separate circuits I should be able to run something without tripping the
circuit breakers. Just plugging in via a 110-type receptacle with the
adapter will trip the circuit breaker if anything besides the refrigerator
is on.
I'd like to be able to run an AC without tripping the circuit breaker. After
all, a 13.5 AC unit hanging out a window in a house will work so why won't a
13.5 AC unit on the roof of a GMC work?
We also visit with other relatives and if they have pre-GFI I'd like to look
for separate circuits that are lightly used and hook in. Of, am I asking for
the impossible and definitely unwise. I don't want to run AC and dry hair or
make coffee at the same time.
Inquiring mind wants to know.
Byron Songer
1978 Royale by Coachmen
Louisville, KY
Personal - http://web.me.com/bnsonger
Eastern States - http://www.gmceast.com
Thomas Phipps wrote:
>
>
> I assembled one just like this. Using standard parts from your local big bock
> home store, it can be made for less than $20. Have not had to use it yet, but
> no reason why it would not work, both sides are isolated from each other,
> unless there is a GFI in the way.
> My coach was (Avion) originally wired for 50A service, but P.O. re-wired it,
> and put both A/C's on the same circuit, along with everything else. Not a
> bright idea, but works. I suspect that a full load would trip all the
> breakers.
>
> Tom Phipps,
> GMC Ex-Avion
Matt Colie wrote:
> Byron,
>
> As Rob noted, the effort is fraught with difficulties.
>
> I take it you mean a thing like
> <http://www.campingworld.com/shopping/item/50-amp-rv-box-adapter/25774>
> Scroll down and read the copy carefully.
>
> The 50 amp (4-pin) that our coaches run is actually 50A - 240V - it uses 2
> sides of a service just like a house does. A 30amp or less system is
> regularly 30A - 120V. As Rob also noted the 20Amp outlet, if it exists, is
> often pulled of the 30Amp breaker (there are code reasons for this that I will
> not go into).
>
> How some ever. . .
> If you run into a power post that has 2ea - 30Amp outlets and breakers, they
> are probably on opposite sides of the 3 wire system - so the hots are 240v to
> each other. If they are and you have all the appropriate plugs, you can make
> that behave like a 30A - 240V source.
>
> Maybe Dan looked at the power posts when he was at DuQuoin and could tell you
> what the chance is that you can make this work there.
>
> I have sometimes had to do such strange things in boatyards and marinas - and
> that with 5L-30 (twist lock) plugs.
>
> Good Luck
>
> Matt
Rob Allen wrote:
> Byron: They only work if the campground 20 amp outlet does NOT have a GFIC
> outlet or breaker, and they have been required by the National Electric Code
> for many years now. So, in most cases they are useless as the GFIC trips out.
>
> Also, some campground outlet systems really only have a 30 amp breaker at the
> source, which supplies both the 30 and 20 amp outlets in the box you plug
> into, the 20 amp outlet having a sub breaker. So, trying to draw more than 30
> amps total trips the supply to that specific pole at the site.
>
> Mostly the thing you are asking about just won't work due to one of the above
> issues.
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
--
Byron Songer
Full-timing to enjoy the USA
Former owner but still an admirer
GMC paint schemes at -
http://www.songerconsulting.net
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| Re: [GMCnet] Opinions or experience with a reverse Y adapter [message #94854 is a reply to message #94838] |
Fri, 06 August 2010 13:11 |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
Karma: 0
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Senior Member |
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| Byron Songer wrote on Fri, 06 August 2010 09:02 |
Allow me to provide a bit more clarification after stating that I'm not an
electrical engineer by any stretch of the imagination. I wire based on what
the picture shows.
Here's my understanding and please correct me if I'm wrong.
Whenever I'm in a campground and I see a 4-pin receptacle, I plug right in
and can run the AC, microwave, hair dryer, etc. When at an RV park with only
the crows feet receptacle, I put on the adapter and plug in to get power
that that seems to work correctly.
I was led to believe that the when plugging in (4-pin arrangement) that it
really breaks into two, separate circuits in the coach. Am I correct or
incorrect? (see answer 1)
My father-in-law has an older home. It has no GFI receptacles to protect
humans (which is the primary design purpose). If I can plug into two,
separate circuits I should be able to run something without tripping the
circuit breakers. Just plugging in via a 110-type receptacle with the
adapter will trip the circuit breaker if anything besides the refrigerator
is on. (see answer 2)
I'd like to be able to run an AC without tripping the circuit breaker. After
all, a 13.5 AC unit hanging out a window in a house will work so why won't a 13.5 AC unit on the roof of a GMC work? (see answer 3)
We also visit with other relatives and if they have pre-GFI I'd like to look
for separate circuits that are lightly used and hook in. Of, am I asking for
the impossible and definitely unwise. I don't want to run AC and dry hair or
make coffee at the same time. (see answer 4)
Inquiring mind wants to know.
Byron Songer
1978 Royale by Coachmen
Louisville, KY
|
1. Yes your understanding is essentially correct. Half the circuits in the GMC come between one hot leg and the neutral, the other half from the other leg and the neutral.
2. If they are 15 amp circuits about all they will support is the refrigerator (about 300 watts) and the converter/charger or buzz box which might take up to 600 watts. If the hot water heater kicks on with another 1000 to 1500 watts (depending on the element) the circuit will be at it's maximum capacity or more. A 20 amp circuit may hold on a bit longer.
3.Most likely because of what else is running (see answer 2). A 13,500 btuh RV AC takes 13.5 to 14.5 amps. That is all one circuit can support, with no additional load on it. Some smaller home window units you see can take considerably less, and will run OK on a local, lightly loaded circuit.
4. You might be able to find two 120 volt circuits without GFIC breakers and run two lines to them and hook up to someone's home, but it would be questionable, especially with limited knowledge of electrical systems.
What I would suggest is you make an extension cord with a 30 amp dryer plug on one end and a 50 amp outlet on the other (4 wires total, two hots, a neutral, and a ground) and ask your host if they will let you unplug their dryer and use it't outlet for your RV hookup. That will give you a total of two 30 amp legs each at 120 volts and you should be in business. The only problem is that you will be overloading the neutral (white) leg for the return, as it is only limited to 30 amps, but I would assume, that on average, your load will total less than 30 amps with only one AC unit. My personal thoughts are that you can do some occasional neutral overload like when the water heater kicks in for 15 minutes, and still be OK.
You also might have to make two different dryer plug systems, one for the older 3 wire (no dedicated ground) homes, and one for the current 4 wire (ground) homes.
I hope that helps some.
Rob Allen
former owner of '76 x-PB
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