Need Some Electrical Help

Paul & Deb

Paul & Deb

Senior Member
Joined
Apr 6, 2011
Posts
3,171
Location
Carlsbad, CA
I'm placing an order for an Onan generator I am having installed and need some advice. As part of the system I will need a 50 amp transfer switch. I have decided on an automatic switch but I have a choice of either a 10 or 12 circuit switch. They are both the same price but I don't know which one I should get. When I look at my power panel in my 337RLS I have 11 breakers and 11 fuses. My totally uninformed feeling is that I should purchase the 12 circuit model but I don't really know if the number of fuses in my panel has any bearing on how many "circuits" I will want to be switching with the transfer switch.

Anyone have knowledge of this stuff that could give me some guidance?

I don't know of this helps pr not:

 
50 amps will be 50 amps regardless of how may circuits involved. Not to be rude but, I would strongly suggest you try to work with a local RV or Marine place to install gen set. Many issues, including back feeding, grounding ,fuel source, ventilation for gen and CO. Onan has a great installer manual that goes in detail how to do it.
Be safe
 
Thanks for responding Scott but your comment doesn't address my question unless I am missing something. I know I need a 50 amp transfer switch but are you saying I could get a 50 amp transfer switch with 1 circuit (if such a thing existed) and that would work? I take it you're telling me that it doesn't matter how many circuits are involved, it only matters that since I have a 50 amp service trailer I just need to worry about getting a 50 amp transfer switch.
 
I have an Onan 5500LP that I have had in two rigs. The transfer switch essentially sends all of its power to the main panel mine does not have it broke down into individual circuits works great. My first install was completed by our local Cummins/Onan dealer. When we moved it into our new Solitude we did it. I don't think local RV dealers work on near as many as the semi repair shops do and they did a good job.
 
Abqscott said:
I have an Onan 5500LP that I have had in two rigs. The transfer switch essentially sends all of its power to the main panel mine does not have it broke down into individual circuits works great. My first install was completed by our local Cat/Onan dealer. When we moved it into our new Solitude we did it. I don't think local RV dealers work on near as many as the semi repair shops do and they did a good job.
Click to expand...

Do you happen to know the brand and model number of your switch Scott?
 
Hi Poppy,

The connections on the transfer switch are not the same as the circuits in the AC breaker panel. The transfer switch (manual or automatic) switches the power coming INTO the breaker panel.

There are four wires feeding power into the AC panel. Two "hot" wires, usually called L1 and L2, red and black or black and black. One common or neutral wire, usually labeled N and white in colour. The fourth wire is the ground or safety ground and is green.

To supply power from an on board generator, rather than shore power, all four of these connections have to be completely disconnected from shore power and appropriately connected to the generator. This is really important, because if not done correctly, the shore power plug prongs can become live and this is dangerous.

A common (no pun intended) misunderstanding is that the ground (green) wire does not need to be part of the switching . . . but it does. This would take a long explanation, but to simplify, ground and common (green and white) come together only at the source of the power. For shore power, this is way back at the main campground power panel . . . but for your generator, this is at the generator.

As noted earlier, if you are not really comfortable with the logic behind this, hooking up the generator might best be contracted out to a qualified electrician.

Just my 2 cents worth . . .

Rob
 
You need a 50 amp automatic transfer switch. It will connect to shore power or generator automatically. I would buy one from a RV place as most electrical supply houses or big box retailers will not understand what you need. When in doubt bigger is always better with electrical stuff. If not sure I would buy 12 circuit over 10. Do a search on Amazon for RV transfer switches ( 50 amp )
Also RVs are a little different than houses as they split the 2 hot legs and may need a bigger ( white ) or neutral wire. Loads can become unbalanced when different demands are put on system.
Hope this helps
 
Model ATS 501

Poppy's 5th Wheel said:
Do you happen to know the brand and model number of your switch Scott?
Click to expand...
I think the brand is Parallax.
image.jpg
 
Hi scott42blue,

Thanks for the endorsement !
I am relatively new to RVs but have been amazed to learn that many campers think plugging into the "50 A" receptacle gives them 20 amps more than plugging into the "30 A" receptacle. They don't understand that the 240 vs 120 voltage difference actually gives them 70 more amps at 120 V . . . and some associated potential risks of bringing 240 volts aboard.

Rob
 
Thanks for all your input.

Would this be what I am looking for: http://www.norwall.com/products/Esc...mp-120{47}240V-Relay-Base-w{47}Terminal-.html

BTW, I am having this installed by a mobile certified RV service tech. They did some work on my previous trailer and I have confidence they will do it correctly. They've already come to the house and spent over an hour surveying the install so I'm not worried about the install. I am buying the parts. He is also setting up my inverter at the same time.
 
That is basically what I have poppy, land power is wired as primary. A lot of people don't like "installed gensets" but with my back totaled out I just can't jerk my two 2k yamahas any longer. When the rain starts I don't have to sweat running out to make sure they are covered or getting stolen. I have a lot of hours on mine now and it has performed flawlessly. A push of the button and it is on quietly. They are not for everybody, but I hope to add solar soon like Tuscon Jim and I will have the best of both worlds. About ever 125 hours I change the oil and keep on running. Btw I use a digital Hobbs meter now. The analog drove me nuts with the click it makes every 10 th of a minute. Found it on line.
 
It looks like you have made a good choice. Be aware than Onans get there cooling air from cut out in floor, it must me sized correctly or warranty might be voided. Other issues are fuel source ( gasoline, propane or diesel ) Vapor from previous and airtight enclosure for gen set should be considered. Also are there any electrical devices non ignition protected in area of proposed gen set ? Most RV stuff is not. Reason why GD and other RV manufactures put gen set in sealed compartment and vent batteries to the outside. Also has a CO detector been consider ? Where will exhaust system go ?
I hope this helps and remember, you are sleeping on top of gen set.
Scott
 
Just got an email from my supplier that my generator and associated parts will be here some time today! Pretty remarkable considering I just ordered them Friday.

Anyway, once they are here I will contact my installer and get it scheduled. I can't wait to see how it goes.
 
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