Sticker says "Start Genny, then plug in cord..."???

The flip side to this is always disconnect before shutting genset down- this is actually more important on many gensets, as the voltage regulators on some will try to keep the voltage under load at ~120vac as the engine spins down.

RoyB wrote:
I wouldn't like plugging into a hot source as well unless the device getting power is turned OFF.

Even when I just plug in drop cord for a lamp I always have the lamp turned off...

Out of curiosity I just read carefully through my Progressive Industries EMS-HW30C owner's manual and nowhere does it say anything at all about first turning off source power with a switch or breaker before plugging in the trailer's main service cable. Rather, under Operating Instructions it says -

1) Plug into AC power.

2) Digital display will read 888 for one second and then begin scrolling the voltage, amps, line frequency, and error code, if any. In addition, the time delay light will flash while the EMS is going through it's countdown and will stop when the unit engages.

Obviously, with electronics in the box, the EMS must draw some power when first plugged in but it's so little that Progressive obviously doesn't consider that draw anywhere near large enough to insist that source power first be turned off before connecting to it. As such, I just make sure my converter's main breaker is off before plugging into whatever source I may be using at the time and let the EMS handle it from there ... once it indicates all is OK then I simply turn on the main breaker ... reverse procedure when powering down.

Drew made an important statement when he said

Breakers aren't meant to be Switches

In RVing, that's hard to avoid, but we can ease the wear and tear on them by not switching any more than we have to, and having the loads OFF when we do switch.

There ARE breakers designed to also be switches, but much more expensive, and places that should use them (like campgrounds!!!) don't.

My Onan 3600 has a red toggle switch on it right by the start switch that you can use for this purpose.

Thats always been the way to start up ANY generator not just those used in RVs... The generator needs to be at full power and settled down before drawing power from them..

Your setup should have circuit breakers or transfer switches on the load side to switch in after the generator starts up... Plug-in generator before starting but have the LOADS switched out... Once it roars to life and settles down then switch in the loads.

I wouldn't like plugging into a hot source as well unless the device getting power is turned OFF.

Even when I just plug in drop cord for a lamp I always have the lamp turned off...

This is what the TRANSFER SWITCH mentioned above is doing... It doesn't switch to LOAD until it sees 120VAC for 30 seconds as described. This will prevent any arcing at the plug contacts if you plugged it in hot... If this was in my setup then I would start the generator with the cord plugged in first... Either way will not have any sparks in this case...

I think you can see where plugging in a trailer with all its loads turned ON will definitely draw some arcing from the plug when you plug-it in being hot with the loads engaged. That is inches away from your hands...

As the saying goes "Learn not to burn"

Roy Ken

Smaller Onans (below 4k) do not do well with any load when starting. So, just KILL the main 30 amp breaker inside the RV and leave the Shore cord plugged in. Everytime you start the Onan, just make sure the 30 amp breaker is OFF and once the Onan is running for 30 seconds or so, turn on that 30 amp breaker which is the exact same as then plugging in the shore cord. Doug

I agree with the posts above, that when you try to start the generator while it is under load, it is a bad thing.

With the auto transfer switch, there is a 30 - 45 second delay built in, where it must see 30 seconds of 120 volts to the 'gen coil' before transferring over to the generator.

If you are inside the RV, and the shore cord is plugged in, then shutting off the 30 amp main breaker will prevent the generator from being under load while starting or stopping it.

Someone also mentioned a 30 amp switch. They make 30 amp toggle switch that looks like a ordinary light switch, and would be wired into the generator feed to the 30 amp receptacle, but shut off manually to 'unplug' it while you start the generator. Yet that still means a trip outside while starting or stopping the generator, and installing a extra electrical box and switch. Turning the 30 amp breaker on and off will do the same thing.



Good luck,

Fred.

On my Onan MQ 4000 I have to unplug from the pedestal and manually plug the 30A shore cable into an outlet in the MH when using the generator. I just reread the startup procedure for the generator in the manual for my MH.

When starting and stopping the generator, you must turn off all electrical appliances, roof a/c and microwave or any outlets currently in use.

There are zero references in the generator section of the manual about when to plug the shore cable into the outlet. Just like the instructions say, I turn off all 110v appliances - although I leave the fridge on AUTO. I then plug the shore cable into the outlet, go inside the MH to start the generator, then I wait a minute or so after it has started so it can settle down, and then I turn on my 110v appliances as needed.

That's it.

loggenrock wrote:
On a power pedestal, I kill the breaker prior to plugging in, then power it up. Not sure I like the idea of plugging in shoreline to "hot" outlet.

Just turn off the main breaker in your rig and there'll be no load on the circuit when you plug into any source, be it shore power, generator, or even an inverter. No way I'd plug into a genset and then start it up - no telling what the waveform looks like before the genset has stabilized. :E Reverse the process when disconnecting - first remove the load by shutting off the rig's main breaker, then disconnect from the genset, then shut the genset down. If this doesn't appeal to you then build yourself a separate breaker box that the rig plugs into and which in turn then plugs into the genset - or shore power, or inverter - whatever the source may be at the time. :)

I think it's to have the generator start up unloaded.

There won't be any problems with the EMS unit with this generator. It's not an inverter generator of any sort, so its output won't degrade or otherwise turn into a square wave output. It produces a sine wave due to the powers of physics and mathematics. Since the EMS has a little time delay built in, that would solve all the problems at once.

You could also install a (suitably rated) switch in the feed to the generator outlet and put it in some convenient location—it doesn't need to be a circuit breaker, just a switch. 30A switches are not hard to come by in the ordinary light-switch form factor if you do a tiny bit of looking around; at least in my neck of the woods, big box stores like Lowes carry them. I put one in my garage to turn my RV outlet on and off so I didn't have to wander over to the electric panel to turn it on and off (and so that I didn't wear out the circuit breaker by switching it frequently).