30 amp plug in a 3000 watt inverter?

[Oranjoose]

I'm shopping for 12v pure sine wave inverters and I'm having trouble finding any that have a 30 amp outlet. They all seem to have typical A/C outlets, which each handle up to 1500 watts, but the inverter is able to handle 3000 watts combined, sometimes even 6000 watts peak.

For the kind of customers buying that kind of product, it seems a bit surprising I'm not finding one with the combined watts going through a 30 amp plug.

Has anyone dealt with this? Did you end up creating a 30 amp outlet using the inverter's output terminals? Anything more straightforward? The inverter I'm eyeing doesn't look like it has output terminals.

I'd rather not hook the inverter directly into the A/C system of the RV. Instead, I'd like to start by just hooking the shore power port of the RV into the inverter, and flipping the breaker on the converter so there isn't a charge loop.

PS: I recognize that 3000 watts would drain a battery bank quickly. 1st, some appliances have a big peak drain but then level out (and I don't want to trip a breaker or fuse on the inverter or worse); and 2nd, with enough solar panels and large enough bank, a load above 1500 watts is not unheard-of out of the inverter.

 

[SmokerBill]

I have a Renogy inverter which has two 15 amp outlets built in, and also has high-output terminals which allow hooking up to loads that are over 15 amps.

 

[John From Detroit]

They make some with no outlet at all. just terminals or wire leads and you supply your own outlet... That is my suggestion

 

[DonTom]

My 4KW inverter only has one 120 VAC outlet, rated 20 amps.

4,000 watts peak / 120 VAC=33.33 amps.

It's rated at 3,500 amps continuous= 3500/120VAC=29 amps. Still well over.

But I never use it over perhaps ~1,500 watts (~12.5 amps) anyway. It is just for the MW oven when I cannot run my generator.

I cannot think of anything else I have used it for.

-Don- Auburn, CA

 

[Gary RV_Wizard]

Are you looking for one that has a 30A/120v outlet? Maybe thinking you will just plug the RV into it? You will need to go the hardwire-your-own route for that. You might find a model with twin 15A outlets that are in-phase so you can parallel them with an adapter to get 30A/120v.

If your plan is to plug the RV into the inverter, know that you need to disable the onbaord converter/charger when doing so. If you don't already know why, we can start another topic to discuss that and related power management concerns.

 

[Oranjoose]

@Gary RV_Wizard
A parallel adapter like this one? https://smile.amazon.com/dp/B01G5OEIHA/ref=cm_sw_r_cp_apa_glc_fabc_G58NDKDPT9YBBBE85DNK?psc=1

I feel like $142 to be quite expensive for something like this, and it very well might not even work. I'd be very curious to see if it would though. I've never heard of someone doing this with two outlets on an inverter.

@Gary RV_Wizard I do recognize I have to shut off the converter. Conveniently, there's already a breaker for just the converter.

 

[Oranjoose]

I have a Renogy inverter which has two 15 amp outlets built in, and also has high-output terminals which allow hooking up to loads that are over 15 amps.

I'm guessing you have something like this: https://smile.amazon.com/dp/B07MKN7MM3/ref=cm_sw_r_cp_apa_glc_fabc_0GS4PSTBRWMGPDMKR6SR

And then wiring up a 30 amp outlet like this one: Server Busy

I suppose that might be my best option.

 

[Oranjoose]

Actually, I opened my battery compartment of the RV and took a cover off of a metal box and found what is in the attached picture. It looks like a hot neutral and ground.

Does anyone know what this is likely for? I'm thinking it's either

1. An electrical box to wire up an outlet so that some kind of electric appliance can go in the battery or on-board generator compartments to be powered up when plugged into shore power. Or

2. That's where an on-board generator can be connected to distribute AC power to the RV, basically like a second shore power input port. The RV had an on-board generator option. No on-board generator was installed, but there are components that lend themselves to an on-board generator, such as a metal ventilated compartment, and fuel hose routed from the fuel tank to just before the compartment, but tied off and capped. That's what made me think that the electric box is generator related.

Any thoughts?

 

[Gary RV_Wizard]

Could be darn near anything, either an inlet or an outlet circuit. It is almost surely 120v rather than 12vdc, but that's as far as I would guess.

 

[Oranjoose]

Could be darn near anything, either an inlet or an outlet circuit. It is almost surely 120v rather than 12vdc, but that's as far as I would guess.

It's helpful to hear that it's not obvious just by looking at it. What's the safest way to test or verify its purpose? I'm nervous to connect to shore and test it while it might be hot. Maybe wire an outlet and test the outlet? Or an even more straightforward method?

It's hard to trace the wires, since they go behind walls. I've attached a picture of the power center panel if that offers any clues.

I'm guessing "refer/gen" is a breaker that has to do with the refrigerator and generator, even though "refer" isn't a substring of "refrigerator". I'm not sure what "6F1" or whatever that breaker below says.

 

[Rene T]

It’s probably GFI not 6F1.

Do you have a volt meter? If you do, just remove the wire nuts and check for voltage between the black and white, black and ground then white to ground using the tips if the meter probes.

 

[Oranjoose]

It’s probably GFI not 6F1.

Yeah that makes more sense.

Do you have a volt meter? If you do, just remove the wire nuts and check for voltage between the black and white, black and ground then white to ground using the tips if the meter probes.

The white and black measured 500mV when the shore was connected, with or without Main breaker on, and measured near 0 when shore was disconnected.

White to ground and black to ground measured near 0 no matter what.

I opened the power center panel, and found this:

It appears that the cable coming from the electrical box matches the cable with the orange jacket out of the gray conduit on the left. Ground is attached to the ground busbar on the left. White is attached to the busbar on the top. And black is attached to the Main breaker 30 amps.

But wouldn't that be shore? Now I'm confused.

 

[Old_Crow]

If there are provisions to add a generator as you said, there are probably provisions somewhere to add the needed automatic transfer switch. Mine is located behind the electrical panel, similar to the one in your picture.

 

[Oranjoose]

If there are provisions to add a generator as you said, there are probably provisions somewhere to add the needed automatic transfer switch. Mine is located behind the electrical panel, similar to the one in your picture.

Thanks for reinforcing my assumptions.

Before trying to tear anything out, I ran a snake camera behind the walls in an attempt to figure out where that mystery box's cable goes.

I took some photos. Pardon the really bad angles and quality. It's really tricky to get good shots back there.

The shore cable (black) and mystery electrical box cable (orange) both enter a compartment behind the wall.

Then in that compartment, they both enter a metal box, and one orange cable emerges. Here's a close-up:

Here's a wider shot of the metal box, showing one orange cable going in, and another coming out.

The single orange cable then goes behind another wall along with another bundle of other cables. Judging from the location, I think that they are all entering behind the power center.

That orange cable I'm pretty sure is what is then connected to the Main 30 amp breaker. Here's a picture of that (orange cable emerging from gray conduit on the left):

I'm not sure if I explained it very well. Basically, I'm not sure what's going on in that metal box where the shore cable and mystery box cable enter, and only one orange cable comes out.

Even if I tore out a wall to access that area, I'm not sure I'd know how to confirm anything.

Is there anything else I can do before I try something more drastic like wiring an outlet and plugging in a generator to see what happens? Sounds like a bad idea.

 

[Old_Crow]

No telling what they've done in that box without opening it, but I suspect that's where the ATS would go if the generator was installed.
The basic formula for an ATS would be, shore power cord and output from generator come in, one main line to power center exits.

 

[Gary RV_Wizard]

I would not assume there was ever an Auto Transfer Switch - simple DIY generator connections often do without that nicety. That junction box may have supported a direct attachment for a generator.

Are there two wires going to that 30A Main breaker? The black from that orange-sheathed wire and some other black? If not, there must be some other junction where the shore power cord feeds to the WFCO load center.

 

[Oranjoose]

I would not assume there was ever an Auto Transfer Switch - simple DIY generator connections often do without that nicety. That junction box may have supported a direct attachment for a generator.

Are there two wires going to that 30A Main breaker? The black from that orange-sheathed wire and some other black? If not, there must be some other junction where the shore power cord feeds to the WFCO load center.

Only one black wire is connected to the Main breaker. The shore power cable disappears into that metal box behind the wall I described in my previous reply (is this what you were referring to as the "junction box?"

Are you suggesting that it's possible that power is fed to the RV at the power center and also to that metal box? What would happen if shore were plugged in at the same time as a generator to the mystery electrical box near the on-board generator compartment?

 

[Gary RV_Wizard]

Are you suggesting that it's possible that power is fed to the RV at the power center and also to that metal box?

Yes. Just a possibility, mind you, but a good one if the rig was equipped with a generator at one time. The orange sheath suggests it is 10 gauge wire, which would be consistent with a 30A, 3600W+ generator.

What would happen if shore were plugged in at the same time as a generator to the mystery electrical box near the on-board generator compartment?

Sparks would fly, but I've seen more than a few that relied on humans never making a mistake. After all, who would be dumb enough to hook up a generator if shore power was present. Right?

 

[Oranjoose]

Yes. Just a possibility, mind you, but a good one if the rig was equipped with a generator at one time. The orange sheath suggests it is 10 gauge wire, which would be consistent with a 30A, 3600W+ generator.


Sparks would fly, but I've seen more than a few that relied on humans never making a mistake. After all, who would be dumb enough to hook up a generator if shore power was present. Right?

I went ahead and pulled the wall panel off to access the electrical behind it.

It's not easy to open that metal box since the screws are on the opposite side and there are only a few inches of clearance. Even a stubby screwdriver wouldn't fit.

I did run that snake camera inside a hole in the side, and found this:

Is that enough to confirm what's going on?

Thanks so much for all the help.

 

[Old_Crow]

Gary, I didn't mean to imply that there was an ATS there. Just that the wires were possibly run the location spec'd out if it had had a generator. Judging by this latest picture, that's what's going on. Probably no ATS in the box, but that's where it would be if it had one.
Basically, the "harness" was built to allow installation of the generator and associated components, but they were not installed when the coach was built. There's probably a blanked out switch hole on the dash or other control panel for the remote generator start switch, too.
I know my Jeep has the spaces for the axle lock switches on the dash and the empty plugs hanging from the harness behind the dash, but since I don't have lockers, there's nothing hooked to those plugs and the switches aren't there.