Thanksgiving Appliance Apocalypse

[OffGridColorado2016]

Quick background: I'm a relatively sharp guy, but have zero electrical expertise beyond knowing how not to kill myself testing outlets and such. Any terminology I use has been picked up recently trying to diagnose this ptoblem, so if I use something incorrectly, be patient...

We are completely off-grid, 100% solar and propane. House in Colorado mountains, built early 2000's. Robust solar system, rarely need to run standby generator (Generac Ecogen 15kw).

Thanksgiving, my wife was cooking. Had a roaster, convection oven, and microwave all running on same circuit at same time. All power on midlevel of house (two circuits/zones at least) down. Every gcfi in every zone is out and will not even reset, including top floor/basement baths on different circuits. No lights/power whatsoever midlevel. Lights work upstairs, and non-gcfi outlets. Basement same. Plugin circuit tester won't light at all at any receptacle, gcfi or otherwise. Positive no hidden/missed gcfis. Pulled all receptacles and no obvious damage/loose connections. (Although they are all backstabbed - can try to transfer to screws on all oulets if someone thinks it would help. No breakers tripped - carefully and firmly reset all housewide, and did main breaker as well. Checked solar inverter and generator - providing power fine, no errors.

I don't know the exact number, but the three appliances pull roughly 60 amps (only load measurement we can display on inverter) when all cycling together, which is astronomical for our system. Running the microwave (about 25-30 amps) for an hour on a cloudy day would deplete the battery bank.

Summary: Midfloor circuits completely dead. All house GFI receptacles tripped and won't reset, even in topfloor zones with working lights. No breakers tripped. Happened after massive powerload on single circuit midlevel.

Being off-grid, I've got 2-3 days to do whatever I can to diagnose before we start having trouble- I'm comfortable replacing/troubleshooting receptacles and breakers, but not anything involving other wiring repairs/changes. I have a cheap circuit tester - would a multimeter or no-contact voltage tester be useful to me? Never used either before, not familiar with them... money's incredibly tight, and have special-needs infant with cardiac problems - need to avoid any expense not absolutely necessary.

Appreciate any ideas you guys might have in advance!!

P.S. all receptacles are unplugged of any appliance or device midlevel in the dead zones...

 

[Jadnashua]

I'm wondering if your inverter might have gotten a really noisy output. Some things cannot handle that, but lightbulbs generally don't care (well, incandescent ones, anyway).

Your amp reading must be at the nominal 12vdc, or so, as no residential microwave would draw that much at 120vac!

 

[Sponsor]

 

[hj]

Everything you describe is consistent with absolutely NO VOLTAGE in the system, so start checking where it all begins.

 

[Reach4]

Everything you describe is consistent with absolutely NO VOLTAGE in the system

except for this:

All house GFI receptacles tripped and won't reset

OffGridColorado2016, I think you should push the test button on one or more of your working GFI receptacles to make sure you knows what tripped looks like. If all GFI receptacles stay tripped, change one out. If that fixes one circuit, buy replacements for all. Is it possible you had a lightning strike?

would a multimeter or no-contact voltage tester be useful to me? Never used either before, not familiar with them...

Yes! Go for the multimeter. You should learn how to use one. I suspect there are a bunch of Youtube videos to start with. Here are some starting rules. Do not use the ohms settings on a powered circuit. When measuring voltages in the car , use a DC (direct current) range at a setting that is above 16 volts. When measuring house voltages, start with the 250 VAC range. Looking at DC with an AC range or AC with a DC range may not show a voltage, depending on the meter.

Where do you like to shop for such things? You may be able to find something useful in the $20 to $30 range.

 

[hj]

Without power the GFCIs will not test and may not reset.