Power Adapter

Probably, provided you are on two different power pole circuits. This adapter is very easy to replicate using parts readily available at Wal-Mart.
Not as weatherproof, but works. I built one several years ago to use with the Avion. You want the 15 amp side to feed the rear a/c circuit and the 30
amp to feed everything else.
Tom, MS II
--
1975 GMC Avion
KA4CSG
 
Rob,
It will have the 30Amp feed connecting to one phase of the 50Amp connector and the 15Amp feed connected to the other phase connection. So in the GMC
you could run 30amps of power on one phase input and 15Amp on the other phase input. So if you 20Amps on the 15Amp side, you would blow the 15Amp
breaker on the pedestal even if you were taking very little from the 30Amp side.

However I can't see the electrical approval agencies being very willing to approve such a device (UL, CSA, etc) To much room for abuse with people
grabbing power from 2 sources (ie a neighbour on a different power transformer). However, like I said I have no Professional degrees in anything, so
I'm not sure how 2 sources of neutral and ground would play together.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
> G'day,
>
> As you read this keep in mind that I am electrically challenged! :)
>
> AdventureRV has this on sale:
>
> http://www.adventurerv.net/cynder-amp-female-adapter-amp-and-amp-male-p-34447.html
>
> Will you REALLY be able to draw 45 amps?
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> Sydney, Australia

Rob,

While I am not one of the EEs here, but I have meddled in power electrics enough to know very well what not to do.

I have seen people try those. I have one the owner THOUGHT was successful. (I have reason to doubt this.)
You might be able to draw 45 amperes total, but:
There better not be a GFI anyplace nearby or it will freak out.
Unless to two circuits are perfectly balanced (and that is a crap shoot) one breaker will open and the other shortly after.
If the internal connection is other than a double up (what power guys call it when you supply both sides of a three wire (GMC native) with a single
source (what a normal 30 to 50 does), you will feed half the house with the 15 leg and the other the 30 and it is any bet which gets which.
Even if you manage to draw 45 amp without fireworks, it will not be 90% of a 50 amp supply, it will more like 45%.

Numbers care be printed, if you care.

There are actually campgrounds that post that if you try to use such a "cheater" arrangement, your power will be locked out.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
Matt,
Good observation on the GFI tripping, Chances of keeping the neutral load balanced with its source are pretty low.

If you need to run 2 A/C units from a 30 & 15Amp pedestal, you would be best to have one of the A/C units wired so you can plug it into an extension
cord and directly to the 15Amp outlet on the pedestal. Then run the second A/C and everything else on the 30Amp the usual way through the coach
wiring.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
What Bruce said.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased
 
> Matt,
> Good observation on the GFI tripping, Chances of keeping the neutral load balanced with its source are pretty low.
>
> If you need to run 2 A/C units from a 30 & 15Amp pedestal, you would be best to have one of the A/C units wired so you can plug it into an
> extension cord and directly to the 15Amp outlet on the pedestal. Then run the second A/C and everything else on the 30Amp the usual way through the
> coach wiring.

If the 15 amp circuit is a gfi it will trip . At least it did when I did it. It probibly would work ok in a gfi if the ground wasn't connected.
--
Roy Keen
Minden,NV
76 X Glenbrook
 
May not be 'correct.' But never tripped a breaker on pedestal or in the coach. GFI was also fine. Very rarely need it. JWID.
Pulled both A/C's in Southern hot Summer. Actually not much need any more, but is in my 'bag of stuff.'
Tom, MS II
--
1975 GMC Avion
KA4CSG
 
It's a miswire finder tool. If either of the camp's hot and neutral are reversed it will instantly trip the pedestal breaker or spark largely if
plugged in hot . Also---We are hoping the TT-30R and 5-20R pedestal are on opposite legs but no guarantee. It will work if on same--- like when using
Onan but neutral will get warm.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
And most camp pedestals are breakered at 20A on the Edison 5-20 receptacle so your total would be 50A. The dongel has a 15Aplug , but that fits the
dual 15/20 recepticle just fine.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
That Avion 50A diagram looks a lot like how GM did it (Kingsley) so what do you need to change?
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
Be VERY careful using more than ONE outlet at a time on RV pedestals, they are not designed to have two cords from the same coach in use at the same time. If you are connected to a double headed pedestal (designed to provide power to two RV's you are probably fine.

----- Original Message -----

From: "roy keen"
To: "gmclist"
Sent: Sunday, October 29, 2017 8:52:14 AM
Subject: Re: [GMCnet] Power Adapter

> Matt,
> Good observation on the GFI tripping, Chances of keeping the neutral load balanced with its source are pretty low.
>
> If you need to run 2 A/C units from a 30 & 15Amp pedestal, you would be best to have one of the A/C units wired so you can plug it into an
> extension cord and directly to the 15Amp outlet on the pedestal. Then run the second A/C and everything else on the 30Amp the usual way through the
> coach wiring.

If the 15 amp circuit is a gfi it will trip . At least it did when I did it. It probibly would work ok in a gfi if the ground wasn't connected.
--
Roy Keen
Minden,NV
76 X Glenbrook

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
This particular device works in a perfict world, out here in the woods, the device is a money maker for commercial electricians, and RV specialist electricians who get to troubleshoot, find, retrench, and hopefully wire it up correctly when they are done (50% chance).
I suggest that if you have two air conditioners, the way to safely power them would be to wire up a 50 amp RV cord into a small electric panel with a 30A circuit breaker and RV receptacle for coach use, and a second circuit breaker on the other power leg with a standard outlet to plug in the second A/C unit.

----- Original Message -----

From: "Rob Mueller"
To: "gmclist"
Sent: Sunday, October 29, 2017 4:45:57 AM
Subject: [GMCnet] Power Adapter

G'day,

As you read this keep in mind that I am electrically challenged! :-)

AdventureRV has this on sale:

http://www.adventurerv.net/cynder-amp-female-adapter-amp-and-amp-male-p-34447.html

Will you REALLY be able to draw 45 amps?

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
What are people running that needs over 30 amps?
2 AC's and a microwave maybe?

Just curious. My coach is wired for 50A but I haven't yet been to a campground that has a 50A circuit, and have never popped the 30A even with Both
AC's running in the 100 degree heat.
We don't have a microwave or an electric water heater through so maybe that's what pushes it over the edge?

--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455
 
Justin Brady schrieb/wrote
> We don't have a microwave or an electric water heater through so maybe that's what pushes it over the edge?

Running the water heater in parallel to the A/C will stop everything
else on 110V for us in the 26' with 6k Onan

--
Best regards

Peer Oliver Schmidt
PGP Key ID: 0x83E1C2EA

'76a Eleganza II 26', VA
'73 Sequoia 23', Germany, SH
 
Justin,

When Helen and I would pull into a campground the first thing I would do is plug in the 50 AMP power and turn on both A/C's to MAX.
By running two of them the pull down time was greatly reduced over running just one even on the hottest days.

Having 50 Amps available meant I could run every 120VAC powered item at the same time and not have to worry about C/B's tripping.

2 A/C's
Water heater
60 amp converter
Microwave
Keurig coffee maker
Toaster oven

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Justin Brady
Sent: Monday, October 30, 2017 8:47 AM
To: gmclist
Subject: Re: [GMCnet] Power Adapter

What are people running that needs over 30 amps?
2 AC's and a microwave maybe?

Just curious. My coach is wired for 50A but I haven't yet been to a campground that has a 50A circuit, and have never popped the 30A
even with Both AC's running in the 100 degree heat.

We don't have a microwave or an electric water heater through so maybe that's what pushes it over the edge?

--
Justin Brady
 
Got it that makes sense.
When I designed mine I wanted to move away from electric, so went propane water heater, stove etc.

It would be easy enough to wire an extension cord into one side of the coach 50A breaker panel so that you could safely use both the 30A and the 15A.

--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455
 
Keep in mind the factory GMC wiring is 14-50 which is TWO 50A legs of 125V coming in to the coach so 100A available from the post compared to 30A on
the TT-30. Big difference. (Ok for the purists most GMCs were breakered at 40A at their load center so only 80A). Running 2 rooftops on 30A is
marginal at best with OEM units as they draw 14-18A running depending on size of unit and conditions. This will cause Voltage drop which is not good
for the units.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
Justin Brady schrieb/wrote
> wanted to move away from electric

Why did you want to move away from electric? (Asked by someone who is
moving to all electric :-) )

--
Best regards

Peer Oliver Schmidt
PGP Key ID: 0x83E1C2EA

'76a Eleganza II 26', VA
'73 Sequoia 23', Germany, SH
 
You must log in or register to reply here.
GMCMI Fall 2026 Rally
Get your shine on at www.cruzingear.co

Share this page

Share this page
Top Bottom
Back