| Generac Prime-Pact 50 Wiring [message #64523] |
Mon, 16 November 2009 16:05  |
GeorgeRud
Messages: 1380
Registered: February 2007
Location: Chicago, IL
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For anyone that has installed a Generac Prime-Pact 50 generator in their GMC, I need a wiring question answered if possible.
I managed to get the unit mounted (it fits beautifully in the old Onan location), and am trying to connect the 120 volt wiring. The old Onan has two large wires feeding through the conduit, a Hot lead that connects with the outer two slots in the receptacle, and a neutral that connects with the center slot. I need to know if I should connect both of the Generac hot output leads (labeled T1 and T3) to the Hot lead, or do I need to run seperate wires to each leg of the receptacle? Also, do I ground the green lead to the coachwork or to the frame itself?
Miguel Mendez has been wonderfully helpful in advising me on the install (many thanks, Miguel), but I cannot get hold of him, his shop phone's voice mailbox is full.
Any electrical gurus out their that can help?
George Rudawsky
Chicago, IL
75 Palm Beach
[Updated on: Mon, 16 November 2009 16:08] Report message to a moderator |
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| Re: Generac Prime-Pact 50 Wiring [message #64668 is a reply to message #64523] |
Tue, 17 November 2009 18:35  |
zhagrieb
Messages: 676
Registered: August 2009
Location: Portland Oregon
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The GMC shore power connection consists of two 110V 25A circuits for a total of 50 amps. One 110V circuit is connected between one of the "outer" pins of the shore cable and the center neutral pin. The other is from the second "outer" pin and the same neutral pin. The Onan bridges it's single 110 volt "hot" lead across both outer pins and its neutral to the center pin to provide both circuits with 110V but with a total of only 30 amps.
Reading the manual that came with your Generac shows it produces two separate 110 volt outputs, one between T1 and T2 capable of 30 Amps, the other between T3 and T2 providing 20 Amps. Generac says the 30A circuit will power a 13,000 BTU air conditioner, the 20A a 11,000 unit.
Were I doing this install I'd first determine which circuit in the GMC powers the AC and connect the 30A hot lead, (T1) to whichever outer pin feeds it. I'd connect T3 to the other outer pin and T2 to the center neutral per the manual. Green is a chassis ground and should be connected in the breaker box.
READ THE MANUAL. If you don't have it go to the Generac website and download it. If in doubt, call in an expert, this is serious stuff.
Glenn Giere, Portland OR, K7GAG
'73 "Moby the Motorhome" 26'
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| Re: [GMCnet] Generac Prime-Pact 50 Wiring [message #64685 is a reply to message #64668] |
Tue, 17 November 2009 20:13 |
Kosier
Messages: 834
Registered: February 2008
Karma: 1
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Senior Member |
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Glenn,
Could I point out that in my 1977 GMC Owners Manual, on page 37,
second paragraph, the first sentence reads: "Your Motorhome's
external power cord contains two 120-volt circuits, rated to
carry 40 amperes each." This would explain the two 40 amp
breakers I remember.
Gary Kosier
77EII & 77PB
Newark, Ohio
----- Original Message -----
From: "Glenn Giere" <glenngiere@gmail.com>
To: <gmclist@temp.gmcnet.org>
Sent: Tuesday, November 17, 2009 7:35 PM
Subject: Re: [GMCnet] Generac Prime-Pact 50 Wiring
>
>
> The GMC shore power connection consists of two 110V 25A
> circuits for a total of 50 amps. One 110V circuit is connected
> between one of the "outer" pins of the shore cable and the
> center neutral pin. The other is from the second "outer" pin
> and the same neutral pin. The Onan bridges it's single 110
> volt "hot" lead across both outer pins and its neutral to the
> center pin to provide both circuits with 110V but with a total
> of only 30 amps.
>
> Reading the manual that came with your Generac shows it
> produces two separate 110 volt outputs, one between T1 and T2
> capable of 30 Amps, the other between T3 and T2 providing 20
> Amps. Generac says the 30A circuit will power a 13,000 BTU air
> conditioner, the 20A a 11,000 unit.
>
> Were I doing this install I'd first determine which circuit in
> the GMC powers the AC and connect the 30A hot lead, (T1) to
> whichever outer pin feeds it. I'd connect T3 to the other
> outer pin and T2 to the center neutral per the manual. Green
> is a chassis ground and should be connected in the breaker box.
>
> READ THE MANUAL. If you don't have it go to the Generac
> website and download it. If in doubt, call in an expert, this
> is serious stuff.
>
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: Generac Prime-Pact 50 Wiring [message #64699 is a reply to message #64523] |
Tue, 17 November 2009 21:48 |
GeorgeRud
Messages: 1380
Registered: February 2007
Location: Chicago, IL
Karma: 0
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I have done some additional checking, and have decided to replace the wiring all the way to the electrical compartment receptacle. I just have to trace the wires to see which lug feeds the 30 amp side (ie, to the front AC lines), and which feeds the rear AC.
The Prime-Pact manual is actually quite complete, and shows the wiring diagram quite clearly. I was only confused as the old Onan wiring has the hot lead attached to both outer 'hot' receptacle connections with a single wire. As usual, doing the upgrade the right way is the only way!
George Rudawsky
Chicago, IL
75 Palm Beach
[Updated on: Tue, 17 November 2009 21:48] Report message to a moderator |
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