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Discussion starter · #181 ·
I am wondering about your Honda EU7000is compared to your new diesel generator. When you used the Honda for your house load, did you ground its frame with a grounding rod? Or did you use it "as is" with its floating neutral? Or did you bond neutral to ground at the generator?
My Honda is setup exactly like jgayman - no special grounding. When we had a major house project I had the electrician add a Reliance socket for the 30 amp gen cord and a Reliance gen interlock panel breaker box which replaced the previous panel.
 
That is how I used my Honda too. I am trying to understand why the diesel generator needs its own ground and the Honda does not. I've been searching on line and watching youtube videos to try to find an explanation that I can understand. I need to go check my new Generac 22kW setup and see how it handles the grounding setup. Thanks.
 
Discussion starter · #183 ·
Bonding and grounding is also confusing to me at a high level. Grounds provide an alternative path for current instead of through your heart should something go wrong however it's a high resistance path and mostly useless (ground rods.) To help me really understand, I should draw a few circuits and chart a few failure situations. Thinking... you want objects (like a panel or generator frame) at the same electrical potential which is zero volts. Never mind, it's happy hour on the ranch 🍷.

I chatted with Ronk (ATS manufacturer) and no pearls of wisdom, actually the failure situation is more obscured. It doesn't seem possible the ATS could have anything to do with the diodes blowing. The ATS interface with the generator controller is just two wires - make or break dry contacts. The generator controller starts and stops the engine.
 
Bonding and grounding is also confusing to me at a high level. Grounds provide an alternative path for current instead of through your heart should something go wrong however it's a high resistance path and mostly useless (ground rods.)

And I always thought grounds provided a low resistance to earth. :unsure: I’m pondering this one.
 
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Yea, I have a 25 kW PTO generator that has no electronics at all. Those generators are fairly bulletproof if things are wired properly. That was the purpose of my previous questions. When you get your parts I would recommend disconnecting everything and run the generator alone. It's highly unusual for diodes to fail. I designed and build a full wave bridge that is used on large GE generators to replace old water cooled bridges. Mine are air cooled. 2000 amp diodes. 6 plane bridge. I have seen some crazy wiring issues and never had a blown diode. I'm curious how stringent their FAT was.
 
Discussion starter · #186 · (Edited)
Earth grounds are relatively high resistance and more suited for diverting some of a lightning strike than protecting life in my opinion. My 55 foot ham radio tower is well grounded as are my radios but this is for lightning protection - actually there is no protection from a direct strike but grounding could dissipate a static charge buildup. We had an up close and personal experience with that on our sailboat anchored in the Florida Keys. We could smell the ozone in the air as lightning was all around us. Our masts were draining off the static charge in the air.

PTO generator:
Simple is good. My motorhome has a 7.5kw Onan QuietDiesel and it's had two inverters fail over ten years. One on their nickle and one on mine. During the recent Valentines day ice-apocalypse, it ran 7x24 for two weeks, thank goodness it didn't fail. We had to run it to keep the fresh water plumbing from freezing which was our main source of water.

Back to the diode thing. My test plan at this point is to run the gen with no load for maybe 30 or 45 minutes. Then I'm going to shut off all breakers and and test the ATS fail-over. Then I'll add a few loads and go back to utility power from generator or go back to utility power with no loads. Or some variation, I'll consult with Aurora before testing.
 
Fortunately I could drive the ground rod in to its full 8 foot depth, around here I never know when I'll hit a solid limestone layer.
Was hoping you'd be lucky. Have the same limestone situation here.

Bonding and grounding is also confusing to me at a high level.
Same here. Researched it a bit for the pool equipment rebuild and about about all that I could figure was that bonding was to maintain an equal potential between the bonded objects, e.g. pool equip, water, pool deck, so there's no shock.
 
Good question. The generator isn't driving specific loads - it's whole house. I'll manage that manually by observing the generator load with a remote gen controller in the house during hot weather testing and again for winter testing. It is my expectation the generator can power everything except perhaps the 3 ton HVAC. We have mini-splits that even our Honda EU7000is will run. Appliances and water heater are propane.

The house was originally fed from the meter with 2/0, I used 2/0 in the circuit from the meter to the ATS Utility and 2/0 from the ATS Load to the panel box next to the ATS and then back to the meter box where I tied into the house 2/0. So we have a 2/0 run from the meter to the house with a bit of a detour. The generator's breaker is 50 amp so I ran 4 AWG from the generator breaker to the ATS Generator lugs.

This morning I finished with grounding. Fortunately I could drive the ground rod in to its full 8 foot depth, around here I never know when I'll hit a solid limestone layer.
chuckle....sure you didn't cut a bit off like i have seen licensed electricians do before? That was 30 years ago.]
I forgot to ask; You don't have a UFER ground? Thats bonding to the rebar in your slab if i remember correctly?
 
Discussion starter · #189 ·
chuckle....sure you didn't cut a bit off like i have seen licensed electricians do before? That was 30 years ago.]
I forgot to ask; You don't have a UFER ground? Thats bonding to the rebar in your slab if i remember correctly?
I'm not sure exactly what "cut a bit off" refers to - maybe the ground rod length? Surprisingly the entire eight foot length went in - I was surprised but the 15 pound weight hammer drill was a great helper. Yup, know about a ufer ground, you are correct. Didn't even think about using the metal in the generator slab for a ground, sometimes I don't plan far enough ahead.
 
I'm not sure exactly what "cut a bit off" refers to - maybe the ground rod length? Surprisingly the entire eight foot length went in - I was surprised but the 15 pound weight hammer drill was a great helper. Yup, know about a ufer ground, you are correct. Didn't even think about using the metal in the generator slab for a ground, sometimes I don't plan far enough ahead.
ufer is a realitively new thing and i didn't think of it at first. Back in the days when i was going to school I worked out of the local IBEW as an inside wireman and the fix was often finding a shorter rod that measured the correct length so i was told. Those guys were amazing. That was in the mid 70's
 
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Discussion starter · #193 ·
Here's a most excellent presentation (PDF file) about generator wiring/grounding from Mike Holt, it was my primary go-to reference when I was doing my research.
 
I was thinking, since the generator is undersized if starting those A/C loads, does the controller have a way to shed load when it starts up? I've read good things about these too:
 
Discussion starter · #195 ·
No automatic load shedding, it will be my fingers :geek:. I've read about soft starts for HVAC - I might just do that for our 3 ton unit. The mini-splits seem to designed from the get-go for soft starts since they are used in many 2nd and 3rd world countries.
 
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Discussion starter · #197 ·
In the house for a break and a snack.

Yes, a possible conundrum. I'll have a good feel for operational characteristics after I run the gen under load for several hours and watch the gen loading. I do expect it to power everything based on our experience with the long outage in February and our EU7000is. There is one scenario where the generator would struggle to keep up with load (or trip its breaker) - the 3 ton HVAC emergency heat strips. We don't need those since we have the little propane fireplace, it kept our house comfortable during ice-apocalypse.
 
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When I installed my mom and dad's standby it had some extra contacts in the ATS. I used a set to lockout the heat strips on their 2 heat pumps. That's really all that John has to worry about. That gen should handle everything else. Worse case it overloads and trips. Trips have to be checked at some point. :cool:
 
Discussion starter · #199 ·
I think the heat strips are on a different breaker, I'll check that out - might be as easy as flipping the breaker off.

Mecc Alte parts will be delivered today ✅ , tomorrow I'll replace the diodes and pray we're good to go.
 
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Yep. Strips should be on a seperate breaker. Using the spare set of contacts on the ATS was just a convenience. If the gen fired up in the middle of the night they could just rollover and go back to sleep.
 
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