Inverter Grounding

[jeffy104]

It has a plug in cord which powers a small computer and some sensors and the computer runs the pump.

[Sunking]

Jeff is the motor hard wired or Plug-N-Cord. We can make this real easy, reliable, and inexpensive by making a UPS.

[jeffy104]

I almost built a set of stairs to the roof of my shop last year- that’s where the panels are, to do the same thing. I still may but not until I have exhausted all other options. I probably have the most efficient and advanced heating system in the Adirondacks. You would think that this would be easy compared to the installation of the system, not to mention the cost but I’m finding out there’s a bit more to it. All the same, I've set up 100 kw onans in the Alaskan bush, built and wired two homes, fought off pirates down near Haiti, had to kill grizzlys to protect my family, came home late one time only to find out my wife was mortgaging the house for helicopter time to rescue me after the coast guard told her they were looking for a body, and the list goes on. But you get the idea- I’m going to have something in place somehow so I’m not tied to a heating system that cost as much as my home and 70 acres. I’m the boss and that darn heating system is going to know it for sure. LOL

[J.P.M.]

I can’t test the inverter because UPS has it but I will when it arrives. I think what you are saying is that the RIB 25401D shouldn’t be used. Maybe there is a transfer switch that I can use here instead of the relay. Plug-n-play will not work. I would have to hire someone to plug it in. This system has to switch ac sources when I am not home- that’s the whole problem- I can’t go anywhere. It would be great if I was home all the time but I feel like a dairy farmer tied to the cows. This system would not be put on line unless I was not going to be home and it would, in fact be plug-n-play 95% of the time because I’m home most of the time. What do you think about the transfer switch idea? I like relays- they seem to work well- I have 7 of them here on the system and the first one I put in about 20 years ago but I understand they have their limitations but I have to have a device to do work when I’m not here.

On the issue of not at home, and for no more than FWIW because I'm ignorant of your roof access situation, when I travel, if I'm gone for any length of time, I cover my water heater's panels in case the power might die. That takes me 2 trips to the roof and about 2 minutes total time or less.

[jeffy104]

Yeah I tried to find a UPS- I looked for quite a while but there’s nothing out there that will do the job without spending thousands. Thousands that I don’t have. The relay I have is top of the line. I forget how many cycles of operation it’s rated for but it’s a lot. Solid state and rated for 10 amps 120 vac. It’s an industry standard relay. I’m still waiting on the inverter but it should be here soon and I will check it as you have said. I’ll let you know what the results are. If I have time today I am going to test the relay without the inverter- I’ll use the grid for both sources of ac and for a load I’ll use a 100 watt bulb. Like you say, a mistake will be bad news. Better to see how it works in the shop. Again, thanks for your input.

[Sunking]

I think what you are saying is that the RIB 25401D shouldn’t be used. Maybe there is a transfer switch that I can use here instead of the relay.

A Transfer Switch is a relay, just do not know anything about your relay. What is bothering me what you want is a UPS. You should have just bought one rather than try to make one.

[jeffy104]

I can’t test the inverter because UPS has it but I will when it arrives. I think what you are saying is that the RIB 25401D shouldn’t be used. Maybe there is a transfer switch that I can use here instead of the relay. Plug-n-play will not work. I would have to hire someone to plug it in. This system has to switch ac sources when I am not home- that’s the whole problem- I can’t go anywhere. It would be great if I was home all the time but I feel like a dairy farmer tied to the cows. This system would not be put on line unless I was not going to be home and it would, in fact be plug-n-play 95% of the time because I’m home most of the time. What do you think about the transfer switch idea? I like relays- they seem to work well- I have 7 of them here on the system and the first one I put in about 20 years ago but I understand they have their limitations but I have to have a device to do work when I’m not here.

[J.P.M.]

JPM Morningstar is just one of hundreds of manufactures that get Bonding and Grounding wrong. The one thing they have in common is the note after Step 4 you can go read. Something to the extent of:: Consult Local Electrical Codes. Not unique to solar but something in common you see with 12 volt topology. Steve will chuckle when he sees that Ham Radio equipment is smeared with all sorts of crazy ground instructions. It is what happens when you let Lawyers write electrical specifications. Check with Local Electrical Codes is CYA.

There are some members if they look agree something is not right. You do not bond a Neutral twice and I bet you know it too. Lots depend on how it is switched in and used. Another thing that might interest you is the use of a 100 Amp fuse on a 300 watt Inverter. 100-Amp Fuse is a great math for a 1000 to 1200 watt Inverter @ 12 volts. A 300 Watt Inverter only needs a 30-Amp Circuit. A fault inside the Inverter may or may not draw more than 100 amps to operate the breaker. It could just sit there and cook until it burned the internal wiring to act as a fuse.

This is not to say the product is not a quality product. Morningstar makes a reputable product, but their Instructions need some work.

Understood and not disagreeing. I'm aware of the basics of electricity, electrical design and accepted practice, and the reasons behind why things are done as they are, but what we're talking about here is outside of areas where I claimed engineering competence before I retired my license so, I defer to your lead in these matters rather than mouth off and leave no doubts as to my ignorance and hubris.

But at this time, I don't need a whole lot of technical acumen to see that the OP is looking at instructions that you're saying are at least partially incorrect and if I read what you're writing correctly, may well be troublesome if not dangerous. So, what's he to do ? Seems to me he's between a rock and a hard place: Take your advice and possibly do something counter to what's written by Morningstar, and in so doing perhaps void any warranty or chance of a successful insurance claim or lawsuit, or follow written instructions and, if you are correct (which I'm not disputing) possibly cause property damage or personal injury, or both ?

Seems to me too that until more information is conveyed between all parties and all the facts and particulars of the application are clear(er), it may be best for the OP to not connect the Morningstar product if only to cover his butt.

That's why I suggested he contact Morningstar and copy them with this entire thread and ask for their version of reality.

Does the NEC or their minions have any definitive wisdom to offer on the matters at hand ?
How about Mike Holt, et al. ?

That there are hundreds of manufactures that get Bonding and Grounding wrong seems strange. Might it have something to do with no two applications being quite the same ?

Still got your 6.

Respectfully,

[Sunking]

Jeff I need to know two things in Post 10 before I can proceed. This can easily be done, just not likely as MS laid out. Example ditch the 100 amp fuse, 30 is more than enough and will help protect the Inverter in the event of an internal fault.

The rest depends on your answers. Can you get me the resistance reading. There is no danger involved, simple and straight forward.

I will be honest with you. Does not sound like you have the skills to incorporate Automatic Switching and Isolating yourself from the Utility, Just one mistake will end in equipment and property damage including electrical fire. This would be extremely simple and safer if you just did Plug-N-Cord manual switching a kid can operate. Unplug pump motor, and plug into Inverter.

[Sunking]

Sunking notes. I'd also give Morningstar a call after sending them copies of this thread and see what they have to say. A P.E.'s opinion

JPM Morningstar is just one of hundreds of manufactures that get Bonding and Grounding wrong. The one thing they have in common is the note after Step 4 you can go read. Something to the extent of:: Consult Local Electrical Codes. Not unique to solar but something in common you see with 12 volt topology. Steve will chuckle when he sees that Ham Radio equipment is smeared with all sorts of crazy ground instructions. It is what happens when you let Lawyers write electrical specifications. Check with Local Electrical Codes is CYA.

There are some members if they look agree something is not right. You do not bond a Neutral twice and I bet you know it too. Lots depend on how it is switched in and used. Another thing that might interest you is the use of a 100 Amp fuse on a 300 watt Inverter. 100-Amp Fuse is a great math for a 1000 to 1200 watt Inverter @ 12 volts. A 300 Watt Inverter only needs a 30-Amp Circuit. A fault inside the Inverter may or may not draw more than 100 amps to operate the breaker. It could just sit there and cook until it burned the internal wiring to act as a fuse.

This is not to say the product is not a quality product. Morningstar makes a reputable product, but their Instructions need some work.

[jeffy104]

Yeah I plan to contact the outfit that makes the inverter after Sunking gets done figuring things out. BTW thanks Sunking for the help. I’m no electrician. I know enough to get by. After too many years I finally installed a remote control for the electric fences with a bright pilot light on the side of the barn here. Now I Just take the remote with me if I’m out there and I can turn it off and back on without hoofing it back and forth. I can tell at a glance from hundreds of feet away if the fence is on. Some of the fence helps keep the bears away from some of the bee hives and I have solar motion lights out there too.

[J.P.M.]

These aren’t vac tubes. They’re from Germany and the heating system is from Austria. I’m 1500’ above sea level I think. In the Adirondacks. Buildings get flattened all the time here from snow load. As the winter goes on the ice forms under the snow and it can be a foot thick on roofs- mostly just from compaction. Most I’ve seen is 48” in one day and that was on top of the 30” we already had. All that weight will easily shatter a solar panel. If I win the lottery I’ll change the angle of the panels- they’re on a roof. Temps here get to 35 below zero F in the winter. Wind chills can be negative 60F. The high today 6/1/20 is going to be 58. It was about 34F this morning but the house was about 72- solar heat.

Thank you for the response.
I appreciate what you write, including flattened buildings. I grew up near Syracuse. Not by my choice, but as a kid I spent a fair amount of time in the winter in/around Watertown and parts east of there between Lowville & Harrisville. Of the folks reading your description, I'm about the last one to question it's accuracy. I also remember seeing a lot of collapsed buildings around the area that were probably older than the dirt they were sitting on.

While anything is possible, from what I now know about solar panel loading, I'm reasonably sure the roof and the structure associated with it in most any environment will probably sustain more damage before the glazing on a panel sitting on such a roof fails from the combined loadings of wind and dead weight from snow/ice.

I will say that, depending on winter occupancy, putting a solar thermal panel at a low slope as you describe seems a not well thought out scheme, but NOMB. Just sayin' that a higher slope would go a long way toward eliminating most of, but probably not all of the overheating problem.

While most of the above is mostly of bunch of moot points with some possible academic and perhaps anecdotal interest, it looks like you have bigger fish to fry with the possible wiring anomalies Sunking notes. I'd also give Morningstar a call after sending them copies of this thread and see what they have to say. A P.E.'s opinion with respect to that P.E's claimed area of competence might be of interest to Morningstar, or at least (hopefully) get their attention.

[jeffy104]

The relay is an RIB 2401D. The inverter is being shipped so when it arrives I’ll check as you say and report. This is the third one I have bought after thinking I could get by with a cheap big box store inverter. This one looks better. Thanks

[Sunking]

OK take your DMM out and set it up to read Resistance. With the Inverter setting on a table completely disconnected and no wiring, measure the Resistance between the Negative Battery Terminal, and Earth Ground Terminal. Reverse the lead polarity and repeat test.

You should get one of two results. Either Open Circuit (OL), and a Short Circuit near Zero Ohms. Report back with results.

Additionally I will need the Relay manufacture and model number

[jeffy104]

OP please throw away the Manufactures Instructions. You will soon learn it is garbage and dangerous. I can help you but you must answer a few questions I need answers to. I will make you a detailed wiring diagram, and it will be safe.

1. Exactly how did you intend to wire the AC Output from the Inverter? This is a Hard-Wired inverter rather than Plug-N-Cord.

2. Sounds like you want to run a water pump with it?

3. Water Pump normally runs on commercial AC?

4. How do you plan to switch from commercial AC to Inverter?

5. Do you have a DMM and know how to read resistance?

The inverter output is going to a RIB relay (DPDT) and then to a duplex receptacle. The pump computer plugs into the outlet and runs the pump. .97 amps max.
It pumps glycol. When the power fails the relay kicks off and makes the change between the two ac sources. Running the relay coil from a 24vac transformer which doesn’t seem to be connected to anything. The relay has 8 or 9 leads on it and after drawing it out on paper I tested it without an inverter and it worked well. I have a dmm not a fluke but works good and read resistance. I admit I’m bit nervous about the relay and switching between the two sources but it seems to make sense.