Inverter: Where to start? Subpanel or No Subpanel?

[tsweez]

Thanks in large part to the community here, this new RV'r just finished his first mod, e.g. creating a new battery location and replacement of the power converter/charger. My next project is installing or at least "preparing" for an inverter installation. I'd like to do as much of this as possible as to control cost, but under no circumstances do I want to sacrifice safety. If I can get this most of the way complete, I'd be a happy guy.

Here's the scoop...

The scope is to install,(as much as is safe) a 12v Cotek 1500 PSW inverter. This inverter has an internal transfer switch and AC breaker. I want the inverter to power all my coach outlets except for A/C and the Microwave. I don't want any manual switching here at all, rather, have inverter setup so it acts much like a UPS in the absence of shore or generator power. Likewise, I want the inverter to bypass should shore or gen power be available.

For reference, my AC panel already has the Microwave and Air Conditioning on their own breakers. The remaining coach outlets (the ones I want on the inverter) are all on the same breaker including the GFCI outlet in the bath. This breaker is also wired to my converter/controller with what appears to be a pigtail of sorts (pic below).

Pic of panel

Pic of breaker w/pigtail

Questions

• Since the coach outlet wiring is already isolated, do I need a subpanel here?
  
• Do I need to separate the house wiring from the exist breaker that also shares the controller/charger?
  

Again, if I need to pay someone to do this, I will. I'm just trying to save as much as I can and move the project in a direction that I know is both safe and effective. The last RV shop I went to was going botch this whole thing and I just want it done right, and for as little as possible.

Thanks again for your help.

Tim

[tsweez]

For reference, the Cotek I have does have a built-in 30amp transfer. It looks like they do have versions that are only 25amp though.

I'll take another look tomorrow to see if this is something I feel comfortable doing. Otherwise, perhaps I can route the romex and pick up a 15amp breaker and have a pro do the rest.

smkettner wrote:
No subpanel. Internal transfer switch is probably not 30a rated so whole house you need to buy a separate transfer switch.

I recommend:

1) Remove that cover and insert a new 15a breaker. Connect the converter direct to this new breaker.

2) The existing 15a breaker that goes to all outlets will feed the inverter input. Remove the romex from this breaker (hot, neutral, ground) and connect the romex to the output of the inverter. New piece of romex connects all three (H,N,G) from the panel to the inverter input. Connect your 12v and you are good to go. (Put the fridge on propane)

[mena661]

Add me to the whole house, turn off the converter, fridge and WH on propane crowd.

[donn0128]

I did a down and dirty and would do it again in a heart beat. I simply wired dedicated inverter outlets where I wanted power.

[OnaQuest]

An original schematic of the existing breaker panel would be more useful than a picture of the front of it. Some panels have a natural break in the feeder bus, after the first breaker position, that makes it easy to insert the inverter transfer switch between that point (electrically) and the rest of the panel. You can easily isolate the air conditioner breaker out of the mix and feed the rest of the panel with the inverter. The remaining panel breakers effectively become a sup-panel.

[time2roll]

No subpanel. Internal transfer switch is probably not 30a rated so whole house you need to buy a separate transfer switch.

I recommend:

1) Remove that cover and insert a new 15a breaker. Connect the converter direct to this new breaker.

2) The existing 15a breaker that goes to all outlets will feed the inverter input. Remove the romex from this breaker (hot, neutral, ground) and connect the romex to the output of the inverter. New piece of romex connects all three (H,N,G) from the panel to the inverter input. Connect your 12v and you are good to go. (Put the fridge on propane)

[BFL13]

Off grid, I use inverters with four 6s as battery bank. I run MW, toaster, and kettle at will, no problems. TV/DVD and various wall warts, no problems.

How? I plug the shore cable into the inverter for "whole house" and everything works the same as on shore power. Of course I have to turn off the converter, put the fridge and WH on gas. No big deal.

No re-wiring at all. No transfer switches. The shore power cord can only be plugged into one place at a time (pedestal, inverter, gen)
Too easy! 🙂

[pianotuna]

Hi,

I use the whole house method. I do have a separate converter and inverter. That allows me to do double conversion when there is only a 15 amp outlet for shore power.

My goal was to have the rv behave as if it were on shore power when ever it was in use. I've pretty much succeeded in that.

[2oldman]

Just do it whole-house and don't run the air or MW. No sub.

Canned answer:

I'll offer an overview of inverter installation.

There are 2 ways it's done: energizing specific circuits, or energizing the whole coach. The first consists of using a subpanel (another electrical panel with breakers), the second uses no subpanel.

As you might imagine, the first is more 'foolproof' (you don't invert your air con circuit) but, much more work to install. The second is easier, and is like plugging your coach into a generator. The inverter becomes just another AC source.

My inverter is done the second way, called whole house. The best part of this install ( I have a Prosine 2.0) is the circuit protection provided when you're on shore power. I have surge and sag protection, and even bad frequency protection. That's a life-saver when you're in a park with questionable power. The inverter becomes the power police for your entire coach.

The downside is whenever you're invertering you must ensure the air and HW are off. But, isn't that what you'd do if you plugged into a generator?

Here's a schematic:

My system schematic