Adding Another Shore Power Input

[WackAway]

I mounted my generator on the rear rack of my 5'r and it worked great during our trip to the NoCal Coast last week. Just run the cables on the ground, hook 'em up and start the Genny.

I was thinking it would be really nice to T-off of the stock shore power lines and add a second input at the rear of the trailer next to the generator. Then, instead of dragging out a 30+ ft heavy cable that sits in the dirt, mud, rain, I can just use a little 3-4 foot cable. Way easier!

Has anyone done this or something similar? Is just T'ing off the stock shore power OK? Or, do I need to consider/purchase/install some other equipment?

Thanks in advance.

[mikestock]

When I had my fiver I installed an automatic transfer switch with thw secondary, generator in my truck bed. The switch was 50 amp but I eventually had a problem with the cheap factory wiring in the switch.
I removed and discarded the automatic switch and replaced it with a secondary 30 amp feeder interlocked with the main 50 amp feed to prevent double feeding. I used a standard 30 amp extension from the 30 amp breaker and kept the male end of the extension cord rolled up in my front compartment. Whenever I fed from the generator in my truck bed I closed the 30 amp feed breaker the interlock disconnected the 50 amp, main breaker.

This worked very effectively and safely. I would never again try one of those automatic 50 amp breakers. I was fortunate that I smelled the wiring burning and didn't burn up my rv. Again, this was the internal connections that got hot. The connectors were cheap, I'm sure, Chinese made, with threads that were easily stripped.

[GordonThree]

Use whatever gauge you're comfortable with. My generator only outputs 13 amps, well within the capacity of a 12 gauge cord set.

[burningman]

I wouldn't use less than a 10-gauge cord.

The transfer switch is perhaps the most convenient but it's another possible failure item.
The cheapest and arguably safest way is the outlet installed in or next to your original shorepower cord compartment, with wiring going back to the rear to a plug that goes into your generator.
You simply plug your shorepower cord into either the generator or the shorepower, there's zero possibility of ever cross-connecting both at same time.
That's something I like having full manual control over and easy visual confirmation of what is connected to what.

[pianotuna]

TVman44 ATS fail. Plugs do too--but they last for 6000 cycles.

[tvman44]

A ATS is the best & safest way to do what you want. By all means do remove power to original input when you do this, because some kid or even an adult will go touch the pins and probably get killed or seriously injured and beside feeling bad about it you will be held liable. 🙂

[GordonThree]

DrewE wrote:
Another is to wire up the generator to what amounts to a permanent extension cord that the main AC inlet is plugged into.

This was the solution I am using. My power entry is in the back of the trailer, but my generator lives up front in the truck bed.

Went to Menards, bought a good quality 50ft 12 gauge extension cord and a bunch of that plastic wire-loom stuff. Cut the outlet end off the extension and fed it down inside the frame rail under the trailer, using the wire-loom stuff anytime it had to pass through a hole or go around a corner. Secured everything with zip ties.

To finish up, I put a 20-amp twist lock connector on the outlet end of the cord. It stays plugged into the trailer unless I'm going for shore-power.

The ten feet or so on the front of the cord is loosely coiled up and secured to the propane tank. When it's time for generator, I unbundle the cord, start the generator and plug it it.

[pianotuna]

Hi,

I cut the cord leaving it 4 feet long and put on a male end. I added a female outlet which is powered by a cord that ends near the generator. I added a 2nd female outlet which is powered by the inverter. I manually transfer to what ever power source I wish to use. It is so nice to have an extra six feet.

[Sport45]

The transfer switch sounds like the best idea to me. Another concern is someone losing shore power and then hooking the second cable up to their generator. If they don't disconnect from the pedestal they will be back feeding power to the system. At best your genny will be fully loaded because it's trying to supply everyone else that lost power. At worst it could kill the electrician trying to fix the problem that resulted in your lost shore power in the first place.

Rather than adding a second shore power input, I suggest you see if you can move the one you have closer to the generator.

[DrewE]

DutchmenSport wrote:

However, you'll need to do some modifications because the plugs on the trailer side are male. If you have power running thorugh one cord, you'll have power in the other cord (regardless if on shore power or generator power). The bare pins on the plug will be live with 110 volts of AC elictricity! So although the idea is good, if you can figure out a way to switch out both plugs you'll be using (on the camper end) so they can end up being female instead of male, it would work.

Swapping the gender of the RV connector is not a solution for a couple of reasons. First, it then requires that one use a male to male cable (sometimes called a "suicide cord") to hook up the shore power or generator. Should the RV end of the cable be disconnected, you have the same problem as above.

Second, it allows shore power and generator power to be connected together. If that were to actually be done, there is a very good chance that the generator would be spectacularly destroyed, with engine or rotor parts flying free and such like. Even if the generator is not running it likely would suffer catastrophic damage. A generator head makes a fine electric motor.

It is essential that only one source of power be able to be connected to the RV at any time. A transfer switch, whether automatic or manual, is one good solution. Another is to wire up the generator to what amounts to a permanent extension cord that the main AC inlet is plugged into.

[n0arp]

DutchmenSport wrote:
The other answer would be to install a cut-off switch for each leg (or both wires), so there would be no back feed to the other plug and only one active at a time.

That is what I recommend using the ATS for instead of a junction box. If it detects power on the B leg, it switches to it, but falls back to the A leg if B leg is unpowered. Or at least that is how the one I installed last year worked.

[DutchmenSport]

I think you could successfully add a second input cord without too much difficulty. All you would need is access to the spot where your current cord actually attaches to the camper wiring. Then, simply attach a second wire at the junction box and run the second cord out a new port you could install near your generator position. What am I talking about?

Here's a photo from my TT. The original 30 foot cord is attached to the trailer wiring inside that silver colored junction box. I simply cut the original cord (I never unhooked it from junction box), and make it about 2 feet long and then attached the male plug. Attached to the mail plug is my portable surge protector with the other end of the surge protector outside the port.

Using this as an example, you could simply attach a second cord with a plug to (your) similar junction point and shove it out.

However, you'll need to do some modifications because the plugs on the trailer side are male. If you have power running thorugh one cord, you'll have power in the other cord (regardless if on shore power or generator power). The bare pins on the plug will be live with 110 volts of AC elictricity! So although the idea is good, if you can figure out a way to switch out both plugs you'll be using (on the camper end) so they can end up being female instead of male, it would work.





As the poster above suggested, attaching a receptacle on the back of the camper, near the generator, would work, but remember, you'd still have the back-feed to the shore power plug with the male end. The other answer would be to install a cut-off switch for each leg (or both wires), so there would be no back feed to the other plug and only one active at a time.

[n0arp]

I'd find a place to locate a box after the existing incoming feed line, and put something like this there. Make sure you use the adequate gauge for the run from the ATS back to the generator, and a quality, weather resistant receptacle as well. Consider wiring in an EMS-HW50C on the ATS output while you are doing it.