Transfer switch blows fuses in shop

[Les Marzec]

I just had an interesting thing happen.  I just got back from from a winter road trip and have my coach next to my house. Been there for a few day and plugged into a 20 amp circuit.  I have done this before to keep the batteries charged.  Never been a problem.  I turn off the coach power when I do this.

Today I noticed that the garage light did not come on, so I checked the circuit breakers and all was fine.  Checked the GFI plugs and found one that had popped.  When I reset it, the lights went out within a second.  I did it one more time and heard the Transfer Switch in the coach fire and the GFI popped.

I checked the Aladdin and it shows only about a 2 to 4 amp draw when not plugged into shore power.  I have a Esco transfer switch. Have not been able to talk to them yet, but has anybody experienced this situation?

Thanks for your help.

[Joel Ashley]

Not all GFCIs are created equal, Les.  The problem is likely not the coach, but rather the GFCI outlet.  Some models are susceptible to momentary micro surges of power such as might occur when a transfer switch kicks in on the circuit, even though the current draw is not excessive.

I think Ed Buker, a regular here on the Forum, can steer you toward a quality replacement, similar to this one he recommended once from Home Depot:  
Leviton 20-Amp Weather-Resistant GFCI
Model # R62-W7899-TKW

Joel

[Les Marzec]

Joel

That thought did cross my mind.  All of the GFI in the shop are only 4 years old so I kind of ignored that possibility.  I have not had trouble before with the GFIs.  

I believe that these came from Home Depot, but I will check it out in AM and see about replacing it.  

Thanks for the tip.

[Richard And Babs Ames]

We have found that if you use an adaptor for a 50 amp plug to 30 or 20 amp service equipted with a GFI the neutral leg of the 50 amp will cause the GFI to trip. You need to plug into a non GFI protected circut.  

[Bill Sprague]

I am not fond of GFCIs.  

My grandparents house had hot and neutral wires strung on insulators in the attic.  When my uncle lived there as a boy he "invented" a work bench light that would slide the length of the bench.  It was suspended from two bare wires on pulleys.  Attached to the pulleys were the wires that fed 110 to fixture.  

In my parents house they insulated the two wires and wrapped them in another layer of insulation.  All the outlets had two holes.  Things we plugged in started showing up with three prongs, so we had to buy adapters if we didn't want Dad to cut off the useless round one "that was only for ground".  

When I was old enough to get my own new house all the outlets had three holes and most of the appliances had three prongs.  Oddly, vacuum cleaners seem to still have only two prongs.  So I guess BJ is either not very well grounded or in a great deal of danger when she is busy sucking up the loose dog fur.

We men do our best to avoid all three wires.  We spend gobs of money on tools that run with lithium ions.  That way we can't be electrocuted like our wives might be with their vacuum cleaners.  

Somewhere between the transistor radio and laptop computer, someone figured out how to stuff Chinese made micro electronics in between the three holes in the outlet.  Then they convinced the building code writers to require them.  I guess they were worried that the hole waiting for the round prong that Dad clipped off might not be doing it's job.  

I'm sure somewhere there is someone that a GFCI has helped.  I have not met them.  So, when a GFCI gives me a PITA, I do what dear old Dad would do, get rid of it.  For 99 cents I can get a serviceable replacement with no electronics.  For about four bucks I can get a really good replacement with excellent connectors and no electronics.  

In some cases, I think getting rid of a GFCI is a serious  improvement in reliability.  For example, I might be gone in the motorhome when the tasty and costly Costco treats in the condo freezer thaw because a GFCI had a bad micro second.   That's not going to happen in my garage.  

Dad would be proud of me.

[Dick Simonis]

Les, I had the same problem and it drove me nuts trying to figure out the why.  Finally just replaced the GFI on that particular garage circuit with a standard outlet.  May be be totally correct but it works.  I still have 6 GFI protected circuits in the garage so I don't mind having that one dedicated to the Beaver.

[Edward Buker]

This is a crying wolf story in most cases. The GFCI more often than not is defective, being too sensitve due to poor manufacturing or age. The GFCI version I mentioned earlier, that is listed in Joel's post, has been used as a replacement in several instances and resolved a false tripping problem. The wet environment version seems to be more fault tolerent.

I would give this type GFCI a try before eliminating one.  The unit is constantly watching for stray current that could be going through you. If there is a current mismatch of 4 to 5 milliamps or more between the hot and neutral it will trip. Because the motorhome is sitting on tires isolated from earth ground and there is so much grounded metal available to be in contact with if working in the bays, the motorhome application is actually one of the places they make sense to be used.

I know the human species was not headed for extinction due to electrocutions before these GFCIs were invented but I do think I would rather the GFCI feel more of the thrill than me.

Later Ed

[Joel Ashley]

Well put, Ed.  Although I too got a chuckle from Bill's expose', one has to lend some credance to the reasoning behind GFCI use in modern construction.  I, like Ed, would not replace one with a standard outlet, especially given the higher risk environment and application we are talking about, and the fact that there are quality GFCIs available as replacements.  In the house, what might be your future liability to anyone hurt because you replaced a code-endorsed device with one that wasn't;  and would your fire insurance be enforceable if you broke code.

A GFCI shuts down a circuit so much faster than a breaker, I'm not sure a person would even know if he'd nearly been dealt a healthy jolt.  As many times as I've had to reset GFCI's in my day, I do wonder, depending on the cause, what might have happened if it weren't for the device.  Better annoyed by a replaceable oversensitive Ground Fault Circuit Interupter than dead or damaged.

Joel

[Bill Sprague]

... Because the motorhome is sitting on tires isolated from earth ground and there is so much grounded metal available to be in contact with if working in the bays, the motorhome application is actually one of the places they make sense to be used. .....

Ed,

Correct me if I'm wrong, but when I'm plugged in to a standard 50 or 30 amp RV hook up there is no GFCI protection from the post. Right?

[Les Marzec]

Thanks for all of the input and humor. It has certainly been a learning lesson about GFCI outlets.

I plugged in to a non GFCI protected circuit and all worked as it should.  Therefore, I will replace the GFCI with the one that Ed recommended.  Since, I have have water features where these outlets are, I want to stay with them for all of those reasons mentioned.  

Also, I have never seen a GFCI at an RV post, even for 20 amp.  

[Les Marzec]

Just changed out the GFCI to the recommended on and it still pops out.  Guess I will have to rethink this.  I have plugged in before with no problem.  Dont understand what changed to start the popping.  I wonder if there is something a miss in the transfer switch?

[Richard And Babs Ames]

What is turnd on in the Beaver? I know one had his engine heat on and that uses a few amps?

[Les Marzec]

I have the coach switch turned off, the electric water heater breaker is off.  Nothing is on.

I am using the same power cords that I have always used.  Also, the coach was plugged in for about 7 days before I started having the problem.  

[Bill Sprague]

Les,

I am not an electronics engineer or electrician.  So take this with a grain of salt, or two.

My understanding is that a GFCI is designed to measure very small, even tiny, electrical changes.  If detected it shuts the circuit down in microseconds.  At first, they were only used in bathrooms where you might be hanging on to the water spigot and blow drying your hair with a faulty hair dryer.  That made a little sense.  

As the primary feed to an entire motorhome,  it may not make sense.  

By their very nature, our generators, transfer switches and inverters make "spikes",  or small electrical changes, as they switch from one to the other.  Today, the relay in the transfer switch might have some dust on it and make a spike tripping the GFCI. Tomorrow, it might not make a spike and the GFCI will be fine.  

Standard RV power poles don't have GFCIs on their 30 and 50 amp circuits.  Everything runs well and safely when we plug into the hookups at our campsites.  Maybe our motorhomes were not made to require or expect a GFCI circuit as a primary power supply.  It may be that using a GFCI circuit to supply power to a motorhome is going to be troublesome.

My understanding is that it takes some fancy equipment to measure and record the momentary spikes that can trip a GFCI.  A simple $5 circuit tester with lights that glow "OK" is enough to determine that the hot, neutral and ground wires are properly connected.  

Good luck.  At least when water leaks you can see the drip.  Amp and volts are harder!

[Les Marzec]

I will check the transfer switch for dust.  We were in two sand/dust storms on our trip.  A lot of fine dust/sand got into the coach and probably in the basement.
That being said, I still am at a loss as to why after being plugged in for a week it started happening.  But lets start with blowing out the transfer switch first and see if that helps.

Thanks for your thoughts and help. I appreciate all of the advise.