Electrical/Generator

[Barg]

Good morning all. This morning the temp was rather cool so I turned on the gas furnace, the electric fireplace (gives decent heat to the living room) and an electric space heater in the garage. We did this configuration all last winter without issue. This morning I decided to exercise the generator at the same time. About a minute in I heard a trip sound (click) and all the wall plugs (refer, gfcis, etc) in our coack went out. But none of the breakers had actually tripped. I reset them anyway to see if that made a difference. Nope. So I shut down the generator and all electrical came back on. That doesn't make sense to me. I've exercised the generator with everything running minus 1 of the 3 ACs. Never a problem. Not sure at all if this is a generator, electrical, panel or user problem or where to start to troubleshoot this issue.
Thanks in advance for any input I may receive.
2020 Momentum 397TH

[ncitro]

Good morning all. This morning the temp was rather cool so I turned on the gas furnace, the electric fireplace (gives decent heat to the living room) and an electric space heater in the garage. We did this configuration all last winter without issue. This morning I decided to exercise the generator at the same time. About a minute in I heard a trip sound (click) and all the wall plugs (refer, gfcis, etc) in our coack went out. But none of the breakers had actually tripped. I reset them anyway to see if that made a difference. Nope. So I shut down the generator and all electrical came back on. That doesn't make sense to me. I've exercised the generator with everything running minus 1 of the 3 ACs. Never a problem. Not sure at all if this is a generator, electrical, panel or user problem or where to start to troubleshoot this issue.
Thanks in advance for any input I may receive.
2020 Momentum 397TH

My initial guess would be a problem with your transfer switch. It determines which source your AC is coming from, the shore cord or the generator. Generally it is not recommended to switch from generator to shore with loads on, I would bet you fried something in the transfer switch with that much draw when you started the generator. I am not super familiar with the generator as installed, hopefully someone will come along who is, but one thing to check is if the generator has an outlet actually on it separate from the rigs wiring, see if you have power there with the generator on. If so, it points even further to the transfer switch.

[TheNescios]

What Neil wrote about the transfer switch being the problem makes sense, as a much younger man I did a stint in the US Navy as an Engineman and we worked with generators, switchboards, and yes, transfer switches. Did a quick Google search and found the text below regarding RV Auto Transfer Switches:

"Transfer switches aren't very high maintenance items but there are still a few tips to remember to help keep them performing well and living long. Firstly, the transfer switch consists of a pair of relays or solenoids that make pass the power through a set of contacts. When these contacts open or close there can be a brief arc while the circuit is broken, especially if the current load is high such as when running multiple air conditioners. Sometimes this can't be helped but other times it can. Ideally, you would switch off your thermostat when starting or stopping your generator in order to minimize the current load which will reduce arc when the contacts make or break the circuit. Sometimes this can't be helped though and eventually your contacts will get pitted and do one of two things. Either they'll fail to conduct electricity or they'll weld themselves tight and won't open. When you find that your electrical devices work on one input, but not the other, it's time to look at the transfer switch."

While I'm not certain, it makes sense there would be some sort of mechanical component to the transfer switch controlled by a magnetic force from the electrical source - having competing sources of electricity, even if the utility or generator has a priority could diminish how smoothly the switch transfers which could lead to a longer arc and internal issues.

We don't have an auto-transfer switch on our RV generator setup, and being honest I prefer it that way as my preference is to manually move from utility power to generator power in a more controlled manner.
Of course, this also means I keep a couple of small flashlights in a few strategic places so I'll be able to see where I'm going and what I'm doing.
(growing up and living for several years in a small town in SE Alaska with regular power outages in the winter has made this a lifelong habit!!)

[ncitro]

What Neil wrote about the transfer switch being the problem makes sense, as a much younger man I did a stint in the US Navy as an Engineman and we worked with generators, switchboards, and yes, transfer switches. Did a quick Google search and found the text below regarding RV Auto Transfer Switches:

"Transfer switches aren't very high maintenance items but there are still a few tips to remember to help keep them performing well and living long. Firstly, the transfer switch consists of a pair of relays or solenoids that make pass the power through a set of contacts. When these contacts open or close there can be a brief arc while the circuit is broken, especially if the current load is high such as when running multiple air conditioners. Sometimes this can't be helped but other times it can. Ideally, you would switch off your thermostat when starting or stopping your generator in order to minimize the current load which will reduce arc when the contacts make or break the circuit. Sometimes this can't be helped though and eventually your contacts will get pitted and do one of two things. Either they'll fail to conduct electricity or they'll weld themselves tight and won't open. When you find that your electrical devices work on one input, but not the other, it's time to look at the transfer switch."

While I'm not certain, it makes sense there would be some sort of mechanical component to the transfer switch controlled by a magnetic force from the electrical source - having competing sources of electricity, even if the utility or generator has a priority could diminish how smoothly the switch transfers which could lead to a longer arc and internal issues.

We don't have an auto-transfer switch on our RV generator setup, and being honest I prefer it that way as my preference is to manually move from utility power to generator power in a more controlled manner.
Of course, this also means I keep a couple of small flashlights in a few strategic places so I'll be able to see where I'm going and what I'm doing.
(growing up and living for several years in a small town in SE Alaska with regular power outages in the winter has made this a lifelong habit!!)

This is exactly right and why I first thought of the transfer switch. They’re easy to get on Amazon and easy to install if you’re comfortable working with stiff 6 gauge wire. As far as I know you can’t replace the contactors inside them, you replace the whole thing.

[Barg]

This info on the transfer switch makes perfect sense. I'll try reducing the current draw then see if the problem repeats itself. Thanks for the input and info!

[ncitro]

This info on the transfer switch makes perfect sense. I'll try reducing the current draw then see if the problem repeats itself. Thanks for the input and info!

It isn’t likely to get better, I’d think once the contracts start to arc over if they weld you’ll need to replace it.

[howson]

It isn’t likely to get better, I’d think once the contracts start to arc over if they weld you’ll need to replace it.

Neil,
Do they make such a thing as "zero crossing" transfer switches? I remember (going way back in the gray matter) that there was such a thing in electrical systems. I'm sure you know they switch when the AC sine wave crosses at 0 volts greatly reducing the arching problem.

Howard

[ncitro]

Neil,
Do they make such a thing as "zero crossing" transfer switches? I remember (going way back in the gray matter) that there was such a thing in electrical systems. I'm sure you know they switch when the AC sine wave crosses at 0 volts greatly reducing the arching problem.

Howard

Boy you’re sending me way back to school on that one but I do remember such a thing. I’ve never seen one for RV, my guess would be it would be cost prohibitive. The ones I’ve seen for 50 amp split phase four RV are priced pretty cheap.

Surge Guard 40100 Basic Automatic Transfer Switch - 50 Amp https://www.amazon.com/dp/B00F4620OO..._X86HFbD1GWFM5

[TheNescios]

Again, I agree with Neil on once the unit arcs and malfunctions, doing any sort of repair that will last is probably not going to happen. Too many of these low-cost electrical/electronic units are essentially "throw-away" so parts aren't available and you pretty much destroy the units getting them open. On the plus side, they're a few hundred dollars rather than a few thousand dollars?
Sounds like a few of us are of similar "vintage"! Still remember reverse power relays and syncing generators in the far reaches of my mind.
For me, the generator and circuit box are pretty straightforward so I'm going to stick with manually transferring power - it's a simple enough system I can make it work with minimal fuss.

[JBill9694]

Prior to exercising the generator I will turn off the shore power at the pedestal and when finished shut down the generator before turning the shore power back on, I usually schedule the exercise for when SHMBO is out and then have to go through the 5er and get all the clocks reset before she gets back.

[Barg]

Sorry so long to follow up on this. The problem turned out to be just this (I'm very thankful!!). One of the 2 30amp breakers had tripped. I reset it, ran it for awhile then started loading it up. No problems. So, in not resetting the one breaker would explain why the 2nd day when the shore was transferring to generator there was an issue. I didn't realize there were breakers on the generator not just in the palel box. Thanks again for the reply comments

[ThePowells]

Glad you got it figured out and let us know.