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Old 09-10-2017, 09:25 AM   #1
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Options for wiring inverters to AC Outlets?

So after scouring google (and the search mechanism on this forum) and not coming up with any real helpful results I figured I'd lean on the wisdom of this forum for some guidance.

Long story short I recently added a Xantrex Prowatt SW2000 inverter to the auxiliary/house battery setup in my '06 Econoline setup.

The new inverter works great but unfortunately the physical location of the inverter makes it somewhat inconvenient to access the (2) 3-prong AC outlets on the front of the unit. Optimally I'd like to run some form of wiring from one of the outlets on the front of the unit to an AC outlet mounted on the front of the electrical cabinet no more than few inches away.

My question is what's the acceptable way of doing this?

Is it acceptable to get a relatively thick gauge extension cord (i.e. properly rated 15amp, 2000w, etc.) cut one end and wire to an outlet on the front of the electrical box? (I have a Blue Sea Systems 15amp outlet I plan to use).

That seems "hacky" to me but the alternative is to buy a 3-prong head at an electrical store, connect it to some heavy gauge wire and wire that to the outlet in the same fashion... i.e. do the same thing, just with a few more failure points along the way.

The Xantrex doesn't have output "terminals" so to do what I want to do will involve "3-prong to outlet" wiring in some form or fashion.

Any advice or pointers to threads on this forum where people have done similar? I have to admit I was surprised that google searching didn't yield any helpful results...


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Old 09-10-2017, 10:16 AM   #2
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It's probably not up to someone's code but it's perfectly acceptable. I prefer a nice, clean look in electric installs and would choose this over running a visible cord or power strip any day.

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Old 09-10-2017, 10:31 AM   #3
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Toddlite, there are multiple parts to the answer to your question.

1. Bad news: There is no way to do what you are suggesting in a manner that complies with the National Electrical Code.

For an installation to comply with the NEC, the inverter must be designed, built, and rated to connect to a vehicle's electrical panel. Yours is not.

2. Good news: An inverter that is used in a vehicle or marine application must carry a UL458 rating. Your Xantrex ProWatt SW IS UL458 rated, so that's a good thing.

What does UL458 have to do with anything? In a residential electrical system, neutral is bonded to ground at the electrical panel. A vehicular electrical system is a little bit different, because sometimes the vehicle is plugged into a ground-based electrical system, and sometimes it is not--and you cannot bond neutral to ground in more than one location.

The short story is that a UL458 inverter will bond neutral to ground when it is not receiving AC power. Your inverter is not designed to receive AC power, so it is built to always bond neutral to ground. On the other hand, inverters that are designed to receive AC power (see discussion of pass-through power, below), have an internal relay. When external AC is present, the relay opens, and the inverter does not bond neutral and ground. When external AC is not present, the relay closes, and the inverter bonds neutral and ground--just as yours always does.

For more details, see post #6 in this thread:

To summarize: you have an inverter that has the correct UL rating for use in a vehicle, but your inverter is not designed, built, or rated to connect to an electrical panel in that vehicle.

3. Connecting to a vehicle electrical panel

This is a conceptual sketch of how an inverter should be wired into a van's AC system.

In order to do this correctly and safely, the inverter must have both AC input and AC output terminals (and the neutral-ground bonding relay discussed above). Your inverter has none of this.

A couple more items to note:
You want the items powered by the sub-panel to have power available to them when you are on shore power. This means that the inverter must have "pass-through" capability. Pass-through means that when the vehicle is plugged into shore power, AC power enters the inverter through its AC input terminals, passes through the inverter unchanged, and then exits the inverter through the AC output terminals, and enters the sub-panel to power those loads.

If you do not have this arrangement, then the only way to power your sub-panel when on shore power is to have the shore power energize a battery charger, which charges the batteries, which power the inverter, which energizes the AC panel.

That's not a practical or safe setup, and it definitely would not comply with the National Electrical Code. Among other things, it means that you will have neutral to ground bonding at both your inverter and at the shore power panel.

Bottom line: while there are inverters that are designed to be part of a van's AC electrical system, your inverter is not. Attempting to kludge the system to make it do so means engaging in electrical no-nos, which generally means creating fire and/or shock risks. Unfortunately, you should either live with the inconvenience of the outlet locations, or buy an inverter that is designed for your desired application, and wire it in a safe manner.
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Old 09-10-2017, 11:31 AM   #4
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I've seen folks with small off grid systems like ours use these with success and not necessarily with just Xantrex inverters. They are limited to 15Amps so keep that in mind.

Inline Transfer Relay

Granted this is assuming you would like to have the van outlet(s) switch between shore power and inverter power automatically. And not just have one dedicated van outlet for inverter power.

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Old 09-10-2017, 12:52 PM   #5
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I think the OP is just looking to extend his outlet mounted on the Inverter to a outlet mounted in a cabinet that gives better access. I guess I might look at purchasing SJO power cord and attach to the outlet. Are you using the BlueSea 360 Panel - 120V AC Dual Outlet #1479? If so I might get the optional back panel AC Insulating Cover 1 Module #1331

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Old 09-10-2017, 01:16 PM   #6
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I agree with Scalf77. A simple extension cord and remote outlet would work great.
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Old 09-10-2017, 09:02 PM   #7
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I have an older 1000W Prosine Inverter with a duplex receptacle......I bought a basic hubbell type grounded plug, wired it into some 14ga romex house wire and that went to a blue plastic junction box with a receptacle in it.

I used residential wire over using an extension cord as it is more resistant to chafing/puncture and is less likely to sustain a flame if things go bad.

If I had a larger inverter capable of outputting more than 15A @115VAC I'd use 12 ga house wire, just like I'd do in the house.
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Old 09-11-2017, 09:51 AM   #8
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Thanks all for the super insightful responses, and guidance, it's really much appreciated.

Glider/ShuttlePilot - I have indeed seen those inline xfer relays and may at some point in the future add that into the mix. That said now that I have enough solar charging to maintain the house battery I rarely hook up to shore power (which is setup to just charge the battery through an IOTA DLS-55 Converter/Charger). I came across this thread a while back would be exactly what I'd plan to do.

Greg/Boywonder - thanks for the links and recommendations on wiring (and the reinforcement that I'm not completely crazy). All the electricity/wiring/components in the van is marine grade stuff (mostly Blue Sea Systems hardware) all appropriately fused and carefully arranged to negate chafing concerns, etc. so I really appreciate the advice of using heavy duty residential wire and appropriate grounded plugs and insulating boxes. That's probably the route I'll go as I just can't get past the hacky nature of chopping an extension cord.

Thanks again all, I really appreciate the input, that's why these forums are great.

Cheers - Todd

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