Inverter hookup

[Gerald55]

A couple of questions about installing an inverter. I'm looking to put one in my 2008 Pleasureway Excel, which didn't originally come with one wired into the 120V system (it did have a small 400W standalone one for the TV only).

Can I simply wire the output of the inverter right into an existing 120V outlet in the RV, e.g., using a male-to-male cord like this:

http://www.amazon.com/Dual-Male-12-Gauge-Connection-Extension/dp/B0035Z13FI/ref=cm_cr_pr_product_top?ie=UTF8

In that case, what happens when I connect to shore power and the inverter is on? Will it just play nice by default, or does it need some kind of internal transfer switch capability to not blow up?

I do an unused transfer switch in my rig since it's wired for a generator but doesn't have one, so maybe I can just use that input?

Any recommendations on brands? I'm looking for 1500W or so, and don't want the dirt cheap variety, but maybe the next level up. I especially want one whose fans are variable, i.e., they only go on if needed to cool the inverter and would generally stay off or run at a low speed if I'm pulling 100W rather than 1500W (which will be very common, e.g., just a laptop).

Some of the "good" inverters I've seen seem to run the fans at nearly full blast regardless of draw.

[Gerald55]

smkettner wrote:
Cord is rated 15 amps because the plug is NEMA 5-15
Need a NEMA 5-20 to get a 20 amp rating.

http://www.stayonline.com/detail.aspx?id=16980

Yup, it's making sense now (as I noted above in my follow up also). These 5-20P cords seem to be rarish beasts (i.e., home depot is not going to be much help) but I'm looking around at local electical shops.

[westend]

Gerald55 wrote:
I should add that the Xantrex has NEMA 5-20R plugs, so perhaps I should be looking for a 5-20P male to bare-end cord rather than then much more common 5-15?

I didn't actually find any of those, but again can I just get anything with a 5-20P plug and cut the other end off?

Yup.
Most guys would just take a piece of 12/2 Romex and install a male plug on one end but 12AWG SOOW is just as good, if not better.

[time2roll]

Cord is rated 15 amps because the plug is NEMA 5-15
Need a NEMA 5-20 to get a 20 amp rating.

http://www.stayonline.com/detail.aspx?id=16980

[Gerald55]

I should add that the Xantrex has NEMA 5-20R plugs, so perhaps I should be looking for a 5-20P male to bare-end cord rather than then much more common 5-15?

I didn't actually find any of those, but again can I just get anything with a 5-20P plug and cut the other end off?

[Gerald55]

OK, so I now understand my suicide cord suggestion was pretty nuts. I'll be wiring up the generator on the 120V side though an IOTA transfer switch (the other input coming from shore power).

Unfortuntely, my Xantrex doesn't have hardware terminals on the AC side (despite being 2000W) but rather a dual GFCI outlet. I want to keep the GFCI functionality, so I think the best option is a quality 3-prong plug into the inverter, with the other end hardwired into the transfer switch?

Most plugs seem to be designed for normal 15A household circuits, but it seems like for 2000W I should be looking for something capable of 20A, and probably 12 AWG?

I found this:

12 AWG pigtail

but not much else yet. It only claims up to 15A, but it does claim to be 12 AWG. I can find extension cords that are 12 AWG and cheaper - perhaps it makes more sense just to buy one of those and chop the female end off?

[Gerald55]

Good point. In fact, the converter already has a 15A breaker for the converter int the AC distribution panel, so if I could remember to turn that off, I guess it would work - but I'm sure I'll forget at some point.

[westend]

So pretty much turning my inverter/converter loop into an inefficient heater. Any good solutions for this? It's kind of like I want the power converter to be wired on the "shore power" side of the system, and have that side isolated from the rest of the 120V system by an isolator, so the converter only kicks in when real shore power is being used?

You could use an isolator relay but a switch is easier to install. Some folks use a circuit breaker if there is a dedicated breaker for the converter. Same for the water heater.

Since power draw from the AC side is not huge for a converter, a 15 amp (or so) rated toggle or panel mount switch can be installed on the face plate of the distribution panel/converter. Remove the power supply wire from the convertor, connect to switch, and install another short wire to the converter. Loop removed. If you get a lighted panel mount switch, just a glance will tell you if the convertor is powered or not.

[time2roll]

Yes if you provide power to the main panel more appliances need to be set to propane or kept off.
Converter needs to be disabled.

Go Power has a transfer switch that breaks out power for the converter but it might prove to be difficult to connect depending on access.

[Gerald55]

One other thing I'm not sure about: I already have a 120V -> 12V power converter which charges the coach batteries when plugged in to shore power (and when running the generator, if I had one). If I get an inverter installed, it seems like that whenever the inverter is on, the converter guy would start pulling 120V and redundantly charging the batteries (which of course are being drained to provide that 12V in the first place).

So pretty much turning my inverter/converter loop into an inefficient heater. Any good solutions for this? It's kind of like I want the power converter to be wired on the "shore power" side of the system, and have that side isolated from the rest of the 120V system by an isolator, so the converter only kicks in when real shore power is being used?

[Gerald55]

That's the type of answer I was looking for, thanks.

In fact, I didn't know anything about a suicide cord, which is why I'm asking here. I've added it to my vocabulary...

[westend]

I have a Samlex and the fan noise is terrible. I now only use the Xantrex. The fan has never engaged AFAIK.

If you want a permanent inverter solution, park the inverter as close as possible to the battery bank and wire the output to your unused transfer switch. You can use a male plug onto the connecting end of your output wiring or disassemble the inverter and wire direct. Some inverters have the hardwire option built in.

Forget anything you knew about a double male suicide cord.

[time2roll]

The unused transfer switch should work fine.

The cord will be hardwired into the transfer switch.
(no cords with two male plugs are legal or safe)

You need to get into the 2000 watt range to have hardwire terminals on the inverter.
Then you just have some #12 romex from inverter to the switch.

I have and recommend Go Power sine wave inverters.
http://www.boatandrvaccessories.com/gopoin.html

[Gerald55]

2oldman wrote:
Since you're asking about an inverter I assume by saying 'generator' you meant inverter.

NO! Don't use a suicide cord. Plug your RV's shore cord into the inverter. That way, you cannot have both shore and inverter on at the same time, which is usually a disaster.

Get a pure sine unit. Brands like Samlex, Xantrex, Magnum and GoPower are good. Stay away from cheapies and most anything you find in an auto parts store.

Thanks for constructive answer. Right, I meant inverter above and have corrected it.

As above, I am looking for a permanent inverter installation, rather than something I hook up occasionally. I am fully time and boondocking 90% of the time, so shore power is unusual, but I don't want anything to blow up if I do plug in (obviously I will turn off the inverter or whatever before I plug in, but it is still important to understand what happens should I forget at some point in the next 10 years).

I looked a Samlex unit that was decent, but the fans run full bore when drawing anything over 50W. Someone posted a how-to on installing temperature controlled fans as a DYI, but honestly if I'm paying for a premium inverter I just want that particular thing to just work out of the box.

[Gerald55]

To clarify, this is about the permanent installation of an inverter in an inaccessible location, and it should be wired into the 120V system permanently.

So solutions like plugging the inverter into the shore power outlet don't work since, well, that's outside and can't be a permanent thing. Similarly for only plugging devices into the inverter as I need them (the inverter is not accessible).

Apparently the approach I suggested is terrible, but I don't understand then what the correct approach is. Many inverters have built-in transfer switches - what is the point of those if not to allow connected shore power to seamlessly turn off the inverter output?

I'm a bit surprised at the hostility. I asked *first* because I'm not familiar with how to do it, and this has been a generally useful forum for "howto" type questions. I understand there are significantly heightened shock and fire risks with 120, so I won't do it right. The response seems to be "if you ask about how to do X, you shouldn't do X"? That doesn't seem very enlightened.

Back to teh actual issue - most inverters, certainly those around the 1000-2000W mark offer only NEMA 5-* plugs for output, so you're pretty much stuck with NEMA 5 on one end. I suggested a NEMA 5 to NEMA 5 cable, which seems to be suicide, but what then is right way?

As I mentioned above, I do have an unused transfer switch since the coach is wired for a generator, but I don't plan to add one. So my initial thought is to use that to guard against both shore power + inverter running at the same time. Is that crazy too?

[hbski]

RJsfishin wrote:
From the questions you ask, I don't think you should do this job yourself.

+2