Shore power and generator

exactly
all these people that say, turn on generator with out unplugging shore power are ignoring the fact that shore is still hot, and your switching hot loads

something that DOES NOT HAPPEN in a power failure
and it does not happen IF shore power is unplugged

several people have come on here after having a failure in the TS and burning out a generator or appliances
by starting the generator while plugged in

wildmanbaker wrote:
Seems like a moot point is being argued. This is no different than a auto-transfer switch in a stick and brick house. You loose shore power, and an auto-start generator starts, when it comes up on power the TS goes to the generator. This protects utility workers from electrocution when residents have a emergency generator. The two sources do not come together at any time. Unplugging shore power before starting your generator, is kind of like changing your oil before putting you MH in storage. The people doing the work, or selling you the oil like it, but what does it buy you?

Yes but even in your scenario the power is off when the genset is started.
At the end of the day . I don't have a whole house surge protector on my house but I do on my RV. The entire RV power supply scenario is more volatile than at the stix and brix.
Unplugging is a simple precaution that does not cost me anything and is easy to do. All I'm wasting is a few step to the pedestal. Makes it a no brainier for me.

Seems like a moot point is being argued. This is no different than a auto-transfer switch in a stick and brick house. You loose shore power, and an auto-start generator starts, when it comes up on power the TS goes to the generator. This protects utility workers from electrocution when residents have a emergency generator. The two sources do not come together at any time. Unplugging shore power before starting your generator, is kind of like changing your oil before putting you MH in storage. The people doing the work, or selling you the oil like it, but what does it buy you?

Transfer switch is NOT IN THE GENERATOR
The TS switches between generator and shore power
The ts is located in the RV at a junction point where the two different power sources meant

Be safe turn off heavy loads like the air conditioner
Unplug from SP
Then start the generator
Repeat the process when shutting down the generator
Turn off heavy loads
Turn off generator
Then plug in shore power

dougrainer wrote:
To do what a lot of Rv'ers do not do, exercise the Genset,

Ok, but you aren't the OP.

2oldman wrote:

kemer wrote:
.. if I can start and run generator while I'm plugged into 50amp service.

I'll bite.. why?

To do what a lot of Rv'ers do not do, exercise the Genset, which you should do twice a month with at least 50 percent load for 1 hour. Doug

lj2654 wrote:
Isn't it possible for a transfer switch to fail causing dual power from the shorepower source and the genset source potentially starting a fire. For that reason I always disconnect from shore power before turning the genset on hot.

No. The transfer switch is designed precisely to make that impossible; that indeed is its primary mission in life. A transfer switch that allows both inputs to be connected simultaneously under any circumstances--including ordinary sorts of failure modes--is a dangerous device and likely would be recalled, just as a circuit breaker that fails to trip under overload conditions would or at least should be.

More likely than a fire hazard is severe damage to the generator and possibly surrounding parts of the RV as it self-destructs. The generator's alternator works equally well as a large electric motor, and if the phase of the generator and the shore power are not synchronized (and they almost certainly would not be), the shore power will nearly instantaneously shift the generator's rotating parts to match it. This causes huge stresses and things breaking and flying off. There are cases of unsynchronized hydroelectric (and other) generators being improperly switched into the grid and causing their rotors to fly through the walls or roof of the generator house. The same thing could easily happen, on a smaller scale, if the generator and shore power were connected together.

Even if the generator were not running, there's a very good chance that connecting shore power to it would cause it to spin and work a good deal of mischief.

kemer wrote:
.. if I can start and run generator while I'm plugged into 50amp service.

I'll bite.. why?

lj2654 wrote:
Isn't it possible for a transfer switch to fail causing dual power from the shorepower source and the genset source potentially starting a fire. For that reason I always disconnect from shore power before turning the genset on hot.

The dual power scenario is hardly possible since the transfer relay (contactor) is made, so that you can only have one connection at any given time. Think of it as double throw switch. . . you switch from one power source while disconnecting from the other.

Another analogy would be a divertor water faucet where you switch from one Y-spigot to the other thereby eliminating the possibility of having both faucets open.

Along with the transfer relay, there is a time delay (relay) that prevents the transfer switch from chattering while the generator is still trying to rev up to its rated voltage.

The shore power would not disconnect prematurely until all these parameters are satisfied. That's why you hardly notice when there is a change-over. It happens in a split second.

All these schemes are all the same no matter what brand of GEN/SHORE POWER control system is concerned.

As an old adage: it is always better to err on the side of caution.

As for me, I always disconnect the power cord before starting the genny. . .although I really don't have to.

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If you make a mistake own it and move quickly to fix it. ( Tooey Courtemanche)

The quote in the post above has good info. Yes, you can start/run the generator while plugged in, but it's NOT a good practice. You'll cause unnecessary wear to the transfer switch and there is always a chance that it glitches or doesn't switch fast enough and can cause a dual load and trip breakers. Even though my previous coach, 2005 Diplomat, was designed to be able to switch while on shore power, I accidentally started the generator one day and sure enough it glitched. Luckily, it only tripped some breakers.

Anyone who says they're doing it all the time is playing Russian Roulette and unnecessarily causing wear of their transfer switch.

The only time you shouldn't be concerned about being connected is when there is a power outage at a campground. In this situation, you can run your generator while still connected. Even if the power comes back on, the generator has priority and will continue to run. Shore power won't turn back on until the generator is turned off.