Generator Prep Wiring

[Rexerito]

I know that this topic has come up before but I cant find the answer I am looking for when searching. I have a 2021 Montana Legacy with Generator Prep. I am looking to add a portable gas generator (Onan 4500i) with this slide out tray

in the generator prep bay. My question is... Does anybody have the wiring to the generator prep box in the basement? I need to understand how to wire it up to a 50 amp or 30 amp wall outlet, so I can plug in the generator. (I dont want to use the shore power plug. Want this to look clean. Thanks in advance!

[dieselguy]

Can't answer your question, but I have one for you. Assuming you will mount the tray in the front storage area when the genny prep is and assuming you're just going to pull out the tray and let the genny run in place ... what's your thoughts on exhaust fumes long term?

[Rexerito]

Because the tray can extend out, not worried about the fumes because it will be under the pin box, we currently set the generator under the pin box to keep it out of the rain and haven't had an issue.

[mlh]

You can get a CO detector that plugs into a 120 volt plugin with a digital readout that displays the exact amount of CO.
My motor home has a generator with the exhaust directly under a window. I have used the CO detector in the camper without a problem.
Lynwood

[twindman]

I have no real knowledge about the Onan and installation, but I thought I read that they barely fit in the front compartment from the factory. I assume you have measured everything carefully. Don't mean to be disrespectful, but just wondered.

[wed]

I have it I’m sure montana will supply it to you . I had affinity install ours.
It works great

[Foldbak]

I have a 4KW LPG Onan in the gen compartment. No slide. The area is sealed with a metal enclosure. As far as the wiring, there is a 50 amp transfer switch that shore and gen connect to.

[Mikendebbie]

There has been several threads discussing the pull out tray idea but I have no idea how to provide links to the threads on this iPad - sorry. But here is a screen shot from one of them…maybe search “route66rambler generator” to find those threads.

[twindman]

If the green thing in Foldbak's post is the Onan, it is much smaller than I thought!

[firestation12]

You may have a transfer switch included with the prep package. If so it'll be mounted above the sheet metal generator enclosure. It'll have a 6/3 Romex wire entering and exiting the transfer switch box. If the transfer switch is there, your installation will be fairly easy.

[Foldbak]

Originally Posted by twindman

If the green thing in Foldbak's post is the Onan, it is much smaller than I thought!

The green thing is a Onan 4000KW LPG. It's in my trailer. Works great! NO 5500KW LPG was available at time of purchase. 12 month wait

[Rexerito]

Ended up getting a tray and mounting a 50 amp box.

[Mikendebbie]

Rexirito - can you provide the model/size of the tray you used?
My unit does not have generator prep installed.
I need to figure out how to anchor the tray.

What is the plywood bottom anchored to in your pics?

[firestation12]

The problem with this arrangement is that the male end whether it's on the cord end or the box, is going to be exposed while energized creating an electrocution hazard. A transfer switch is needed to make this transition.

[Rexerito]

Originally Posted by firestation12

The problem with this arrangement is that the male end whether it's on the cord end or the box, is going to be exposed while energized creating an electrocution hazard. A transfer switch is needed to make this transition.

I have transfer switch. Just didn’t show it.

[Mikendebbie]

Originally Posted by firestation12

The problem with this arrangement is that the male end whether it's on the cord end or the box, is going to be exposed while energized creating an electrocution hazard. A transfer switch is needed to make this transition.

I am not an electrician and don’t understand the statement.
My cord and male end is similarly “exposed” whether it is plugged into the campground pedestal or a generator sitting next to the pedestal (or in the bed of the truck). In the photos in post #12 - my generator will be on the slideout tray - not sitting on the ground.

I always assumed that transfer switches were needed for permanent genny installs like Foldback shows in post #7.

[firestation12]

If Rexerito were to employ his generator add on in the manner pictured (omitting the transfer switch), this would create a shock hazzard at the back of the trailer where the shore power is normally connected. If a child were to lift the lid covering the camper's inlet, the male prongs would be energized if the generator was running in the front compartment. Conversely, if the shore power cord was connected, the male parts the generator cord plugs into (in the front compartment), would also be energized. Imagine if the power to the pedestal were to be interrupted and Rexerito were to plug in his generator, but forgot to disconnect the shore power cord......when the power to the pedestal restores, a direct conflict would occur between his generator and the shore power.....BOOM! The purpose of the shore power is to allow only one source of power to be introduced to the circuit breakers of the camper. Some of the older tow behinds and class C motor homes with 30 amp systems, had a compartment that contained a short 30 amp cord terminating in a male plug. The male plug could be connected to either the generator female or the shore power female, but not both. This worked because there was only one place to introduce power. In Rexerito's 5th wheel, he created a 2nd place to introduce his generator at the opposite end of the 5er.

[mlh]

I think the way Mike has his wired is the way my motor home came from the factory. You either run the trailer cord to the generator or the camp pedestal. This isn’t unsafe but it is reliable no transfer switch to go bad.
Lynwood

[Rexerito]

I had the generator prep package with the wiring to the the transfer switch already installed. If you look at the pictures you can see that I had to cut the pre-installed sheetmetal and push it up to make room for the generator height. I will send pictures later today of the wiring at the preinstalled junction box to the transfer switch.

[wed]

You can use the shore power but I brought a 50 amp in the compartment and use a step down to a 30 amp