Another Inverter Question

WilisWilis Solar Expert Posts: 84 ✭✭✭✭
Hi,

Just a quick question before I do something stupid. I read the 2 post about inverters and generators where the ground has caused trouble. Like letting smoke out of the inverter. I installed a small solar system about 4 weeks ago. Everything has been working just as Dave ext. 105 at NAWS said it would. I have an Magnum MS-4024AE inverter. The batteries charge fine from the PV's. If I have several days of rain, as we have had the last couple of weeks, I can do a charge from the grid with 240v ac. I have the 240v inverter for a backup for a well pump and running my ref and freezer, that is working fine. Now the last part I was going to tie to the system and try was a generator, so if the grid was down and I needed to charge the batteries I could do it that way. The generator is an Coleman Powermate Powerbase PM54-4000. It is single phase, voltage 120/240, Amps 33.3/16.7, 4000 watts, Power Factor 1. One thing on the base plate I dont know about is: insul cl: F. What does that mean? The output of the gen is 2 110v and 2 240v outlets. I have used the gen to pump water before. I have an welders plug outside and just pull the main power and can run many things in the house. Everything works that way. My 240v ac line from the main panel would also go to the inverter is I turned on the breaker. Everything in the house would be just like grid power and that has worked many times before. I do ground the gen to the grounding rod by the electrical panel when I run it. Will this do something bad to my new inverter? I would feel bad if it did. How do I test this out without just a smoke test? Wil

Comments

  • WilisWilis Solar Expert Posts: 84 ✭✭✭✭
    Re: Another Inverter Question

    Wow! not many posts that dont get even one reply. Bill gives good answers and usually post something. After I have thought about what I should do with the gen and inverter, I have decided it is to risky to try and do something bad to the inverter. I have decided to buy a good battery charger. That would be much cheaper if something did happen. Something I have always wanted and never spent the money for. I know some chargers have a setting for deep cycle batteries. Does anyone have a battery charger that works well on deep cycle batteries? Would like to know the brand and model. Wil
  • BB.BB. Super Moderators, Administrators Posts: 30,520 admin
    Re: Another Inverter Question

    I will take a closer read (don't have the time at the moment)... I fear giving detailed electrical answers across the Internet--there are just so many assumptions that can go wrong and hurt somebody.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 30,520 admin
    Re: Another Inverter Question

    Insulation Class "F"--This is just the maximum temperature rating of the motor (or generator) insulation.

    From the Magnum 4024AE owners manual:
    The MS-AE Series inverter/charger uses both AC and DC power; however the AC electrical system is isolated from the DC electrical system by an internal transformer. Although this inverter/charger has two electrical systems, each electrical system must be properly grounded and connected to a common “earth” reference; refer to fi gure 2-4.

    That is good--you can independently ground the DC (typically battery negative to earth ground) and AC sides of the inverter (Case to earth ground and Neutral White to earth ground) and not let out the magic smoke.

    From page 12 of the manual, the wiring diagram looks like it will support AC Neutral bonding to safety ground and DC to safety ground...

    I am not the expert in this--but I do not see any "gotchas" in the design.

    I could not find a generator manual on-line... Some generators may bond the neutral to frame ground in the generator itself, and others many not.

    There can be issues if you have the Neutral to Frame and/or Safety Grounds bonded in two or more locations.

    Typically, you would want only one Neutral to Earth/Safety ground in the main home panel, and no other Neutral to safety or earth grounds anywhere else.

    If there is a a Neutral to Earth/Frame ground in the genset--it should be something that you can disconnect inside the wiring box (I am guessing here).

    When the genset neutral bond is opened (not connected)--then connecting the frame of the genset to the home's earth rod should be perfectly fine.

    If the genset neutral is bonded to the frame--you can have problems with current flowing through the Neutral/Safety ground wires (neutral and green wires sharing current flow)--not something you want to happen.

    Before you follow my instructions--see if somebody else who has worked with a similar setup has any other suggestions.

    Sorry--I don't really have any more information to say anything past the above.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: Another Inverter Question
    Wilis wrote: »
    I do ground the gen to the grounding rod by the electrical panel when I run it. Will this do something bad to my new inverter? I would feel bad if it did. How do I test this out without just a smoke test? Wil

    Hey, it was my birthday on Saturday, and I spent the weekend helping my 22 y.o. son buy his first motorcycle (1976 Yamaha DT175C Enduro (street legal) - 1600 original miles - $275). So, sorry I didn't get you an instant answer, but you'll get over it.


    Okay, about your grounding question...

    Neutral to ground bonding should happen in one place only. The best place for it is in the main electrical panel, and the panel on your building almost certainly has it done.

    So, your generator should NOT have its neutral and ground bonded together.

    Powermate.com doesn't list the manual for your specific model:

    http://www.powermate.com/productmanuals.php?cat_id=3

    Which is just as well I suppose since all of the "manuals" that I checked on that page are actually just inserts showing how to install optional battery kits or wheel kits.

    I can't seem to find a manual online for that generator - however, I did find a wiring diagram and it clearly shows neutral being bonded to ground.

    Now, exactly HOW is that done? Dunno, you'd have to tell me. Some generators (particularly those designed to hook to building electrical panels) make it easy - there is a ground lug in the electronics box and to isolate the neutral from the ground you just disconnect the neutral from that ground lug.

    Your owner's manual might explain how to isolate or "lift" the neutral to ground bond. If so, then you definitely want to do that when the generator is connected to your building's electrical system.


    If you don't, will bad things happen to your equipment? Dunno, maybe - but either way with the neutral and ground bonded at the generator AND in the main panel, you are not in compliance with the National Electrical Code.
  • WilisWilis Solar Expert Posts: 84 ✭✭✭✭
    Re: Another Inverter Question

    Hi,

    Sorry I wasn’t trying to rush anyone, just being new. The other posts were answered in minutes after I posted. Sorry.

    The gen is about 20 years old but in good sharp. Very few run hours on it. Don’t have a manual. There is a green wire coming from the gen housing to a bolted on ground lug. That most likely is the ground pictured in the downloaded picture. Should I run a ground to the main house ground rod or not? I have ran it both ways before the solar and it didn’t seem to make much difference. I was able to run lights, well pump, tv etc.

    I have several questions about my whole ground system? I feel I have the correct size wire for grounding. I did read one post about less grounding is best for lighting. I have an 8 ft rod at the PV’s for frame ground. I have an 8 ft rod at the basement wall about 35 ft away from the PV’s. A ground wire is running between these two ground rods. A 10 ft ground wire is running into the house to the e-panel. This is connected to the equipment ground in the e-panel. From this buss I have grounded the inverter equipment ground, the controller equipment ground, combiner equipment ground. From the inverter I have ran the AC 240v to an AC distribution box about 10 ft away. This boxes equipment ground is ran to a copper water pipe that runs by the main house AC electrical box with ground clamps to the house main 200 amp box, which is grounded to an 8 ft rod of its own. The buss in the AC solar distribution panel is the same as AC neutral. So the AC box and the other equipment have the same potential I have connected a jumper in the e-panel between the equipment and the AC natural. Is this OK? I see in the inverter manual this is one way of grounding. Everything seems to work. I can grid charge the batteries through the inverter. The PV reading on the controller look ok, the Tri Meter 2020 values seem to look ok. The batteries voltage and SG seem good. You can see why I was questioning about the gen. The wire from the gen would be the same as grid power to the system, so the inverter should think it is just AC, but what if??? Thanks for the help. Solar is coming, but a little different then AC wiring. If you need more info I will be glad to try to explain better. Wil
  • BB.BB. Super Moderators, Administrators Posts: 30,520 admin
    Re: Another Inverter Question

    The whole Neutral/Safety ground is a bit of kluge (in the code). There are good reasons to connect the two together in one place--but as the installation gets more complex--the problems with grounding become more complex too.

    It is unlikely that you will have a problem--since the inverter itself is isolated. One rare occasions, people have had problems with the Neutral/Safety Bond connection blown from too much current (last I remember was a person with an electronic based voltage regulator or something and was blowing that).

    The typical problem is when the DC and AC grounds/neutrals/negatives are mixed/interconnected in two or more places...

    20 amps of 240 VAC is 4,800 watts...

    That would 200+ amps of 24 VDC at 4,800 watts if the battery negative lead, for example, is grounded to the safety ground in two places... And there is a couple neutral bonds (one in the e-panel, another in the generator, maybe the DC network is ground in two places too)--and if the neutral/green wire only carry 20% of the DC battery current--that is still 40+ amps--enough to smoke the wiring in a 5kW genset...

    If the interconnects between the DC and AC networks are only done in one place (say the 10' ground rod)--then there is no way for a common current to flow in "both" DC and AC connections.

    You could also get some DC current to flow in the AC windings of the genset--Also DC current in AC alternators (and transformers) is typically bad news.

    Does that sort of make sense?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • WilisWilis Solar Expert Posts: 84 ✭✭✭✭
    Re: Another Inverter Question

    Thanks so much Bill. Thanks to everyone for making this forum work so well. Wil
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: Another Inverter Question

    Holey moley! Lemme see if I can step through and parse this...

    Wilis wrote: »
    I have an 8 ft rod at the PV’s for frame ground.

    PV frame ground rod - check.

    I have an 8 ft rod at the basement wall about 35 ft away from the PV’s. A ground wire is running between these two ground rods. A 10 ft ground wire is running into the house to the e-panel. This is connected to the equipment ground in the e-panel.

    E-panel ground rod - check.
    (Connected to PV ground rod.)

    From this buss I have grounded the inverter equipment ground, the controller equipment ground, combiner equipment ground.

    Solar equipment grounded to E-panel ground bus - check.

    From the inverter I have ran the AC 240v to an AC distribution box about 10 ft away. This boxes equipment ground is ran to a copper water pipe that runs by the main house AC electrical box with ground clamps to the house main 200 amp box, which is grounded to an 8 ft rod of its own.

    Distribution box ground - box to water pipe to main panel...

    So you are depending on the water pipe alone (and the neutral...) to provide the equipment ground tie-in between the "solar derived" AC system (distribution box) and the main panel?

    The buss in the AC solar distribution panel is the same as AC neutral.

    Do you mean the ground bus is the same as the neutral bus? I.e., a single bus bar. Is that bar screwed directly to the box or is it sitting on plastic mounts and then bonded to the box somehow?

    So the AC box and the other equipment have the same potential I have connected a jumper in the e-panel between the equipment and the AC natural. Is this OK?

    Okay, so in this system, the neutral is bonded to ground at: A) the e-panel, B) the solar AC distribution panel, C) the generator and D) the main electrical panel.

    If that's correct, then if it were me, I think I would:

    1) Isolate neutral from ground at A, B and C, and keep the neutral->ground bond at D (main panel, the proper place for it). This means adding either a proper insulated neutral bus in B, or disconnecting the existing neutral bus from ground and adding a proper ground bus.

    2) Install a proper equipment ground wire from B to D.

    3) Leave the water ground between B and D - the water ground is a valid grounding electrode, but I wouldn't consider it a proper equipment chassis bonding (though it may be perfectly legal the way it is).

    4) Isolate the neutral from ground in the generator (if possible...may not be).

    5) If possible to isolate neutral and ground in the generator, then ground the generator, if not, then I would isolate the generator from ground and let its neutral handle the grounding.


    I see in the inverter manual this is one way of grounding. Everything seems to work. I can grid charge the batteries through the inverter. The PV reading on the controller look ok, the Tri Meter 2020 values seem to look ok. The batteries voltage and SG seem good. You can see why I was questioning about the gen. The wire from the gen would be the same as grid power to the system, so the inverter should think it is just AC, but what if??? Thanks for the help. Solar is coming, but a little different then AC wiring. If you need more info I will be glad to try to explain better. Wil


    Taking a quicky look at an E-panel wiring diagram, the only place I see where neutral and ground are bonded is in the main panel:

    http://www.midnitesolar.com/pdfs/e-panel_gridtie.pdf
  • WilisWilis Solar Expert Posts: 84 ✭✭✭✭
    Re: Another Inverter Question

    Dwh,

    Looks like I need to have one of you experienced solar people here in TN. I will try to answer your post.
    "From the inverter I have ran the AC 240v to an AC distribution box about 10 ft away. This boxes equipment ground is ran to a copper water pipe that runs by the main house AC electrical box with ground clamps to the house main 200 amp box, which is grounded to an 8 ft rod of its own.
    Distribution box ground - box to water pipe to main panel...

    So you are depending on the water pipe alone (and the neutral...) to provide the equipment ground tie-in between the "solar derived" AC system (distribution box) and the main panel?"

    I could run this equipment ground back to the e-panel and ground it at the equipment ground and to the box if that would be better. The bus is the AC box (Homeline Load Center HOM6-12l100 with Square D breakers)and is sitting on plastic. It is the neutral for the 240V but I do have this grounded to the AC box also. If I made these two different grounds that would isolate the AC neutral and the equipment ground.
    I see in the inverter manual this is one way of grounding. Everything seems to work. I can grid charge the batteries through the inverter. The PV reading on the controller look ok, the Tri Meter 2020 values seem to look ok. The batteries voltage and SG seem good. You can see why I was questioning about the gen. The wire from the gen would be the same as grid power to the system, so the inverter should think it is just AC, but what if??? Thanks for the help. Solar is coming, but a little different then AC wiring. If you need more info I will be glad to try to explain better.

    In the Magnum owner's manual on page 14, I Fig. 2-6, Multiple Connections to DC Ground Rod (Method 2) was one way to ground. That was what I was trying to do.

    http://magnumenergy.com/Literature/Manuals/Inverters/64-0007%20Rev%20A%20(MS%20Series).pdf


    Just trying to be safe and not destroy my new equipment. Everything has been working so well. I could pay someone to do the work, but what would I learn? Thanks for the help. Wil
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: Another Inverter Question
    Wilis wrote: »
    Dwh,

    Looks like I need to have one of you experienced solar people here in TN. I will try to answer your post.

    Quote:
    "From the inverter I have ran the AC 240v to an AC distribution box about 10 ft away. This boxes equipment ground is ran to a copper water pipe that runs by the main house AC electrical box with ground clamps to the house main 200 amp box, which is grounded to an 8 ft rod of its own.
    Distribution box ground - box to water pipe to main panel...

    So you are depending on the water pipe alone (and the neutral...) to provide the equipment ground tie-in between the "solar derived" AC system (distribution box) and the main panel?"


    I could run this equiment ground back to the e-panel and ground it at the equipment ground and to the box if that would be better.


    Um...we are talking about the "AC Distribution Box"? That box takes the feed from the inverter and then feeds it to the main panel? That should already be tied to the inverter as part of one big "equipment grounding system".

    I.e., there should already be a ground wire of appropriate size run from the inverter to the distribution sub-panel alongside of neutral and the 240v hot wires. If there is no "equipment grounding conductor" tying the inverter and that sub-panel together - then you should put one in.

    The bus is the AC box(Homeline Load Center HOM6-12l100 with Square D breakers)and is sitting on plastic. It is the neutral for the 240V but I do have this grounded to the AC box also. If I made these two different grounds that would isolate the AC neutral and the equipment ground.


    Yes, disconnect whatever device (screw, strap or wire) that is bonding the neutral bus bar to ground in that sub-panel. Use a separate ground bus (doesn't need plastic isolaters) and run the neutrals into the neutral bus bar and the grounds into the ground bus bar.

    Grounds in the ground bus bar in the sub-panel would be:

    From inverter
    To main service panel
    To water pipe

    Plus the equipment grounds for whatever branch circuits you are feeding from that sub-panel.


    Quote:
    I see in the inverter manual this is one way of grounding. Everything seems to work. I can grid charge the batteries through the inverter. The PV reading on the controller look ok, the Tri Meter 2020 values seem to look ok. The batteries voltage and SG seem good. You can see why I was questioning about the gen. The wire from the gen would be the same as grid power to the system, so the inverter should think it is just AC, but what if??? Thanks for the help. Solar is coming, but a little different then AC wiring. If you need more info I will be glad to try to explain better.


    In the Magnum owner's manual on page 14, I Fig. 2-6, Multiple Connections to DC Ground Rod (Method 2) was one way to ground. That was what I was trying to do.

    http://magnumenergy.com/Literature/Manuals/Inverters/64-0007%20Rev%20A%20(MS%20Series).pdf


    We may be looking at different manuals. In the one you linked to, Fig 2-6 shows how to attach a battery cable...


    Anyway, from the manual linked above:

    If you look at the various methods in Figs 2-11 through 2-15, you will see that in all of those diagrams, [on the AC side of the inverter] the neutral to ground bond is done in the main electrical panel - and no where else.

    Also note that there is a green "equipment grounding conductor" tying all the chassis together.

    Now, as to the neutral to ground bond, the manual states:

    "2.6.2 System Bonding Jumper

    The MS Series inverter does not include an internal bond between the Grounded Conductor (AC neutral/DC negative) and the equipment grounding terminals. This bond [System Bonding Jumper (SBJ)] is usually done in the main distribution panel for each electrical system.

    CAUTION: There should be one and only one point in each electrical system (both AC and DC) where the Grounded Conductor is attached to the Grounding Electrode Conductor.

    ((( Okay, the grounding electrode conductor is the wire that ties all the metal parts of the system together. The grounded conductor is what the neutral (on the AC side) or negative (on the DC side) becomes *after* you bond it to ground. - dwh)))

    AC Side – The size of the System Bonding Jumper (SBJ) in the AC electrical system is based on the area of the largest AC ungrounded conductor. In accordance with the NEC, use Table 2-4 to determine the System Bonding Jumper size compared to the largest AC ungrounded conductor.

    DC Side - The size of the System Bonding Jumper (SBJ) in the DC electrical system must not be smaller than the DC Grounding Electrode Conductor (GEC – DC) used, which is determined from the grounding method that will be used (see section 2.6.1)."


    Just trying to be safe and not destroy my new equipment. Everything has been working so well. I could pay someone to do the work, but what would I learn? Thanks for the help. Wil


    To sum it up:

    It doesn't matter how many grounding electrodes (ground rods) you have. The more the merrier.

    All the metal hardware - panels, boxes, chassis, frames, enclosures etc. - needs to be tied together with an equipment grounding conductor (green wire) into one big grounded chassis - which is connected to one or more grounding electrodes via grounding conductors.


    On the DC side, you need to bond negative to ground - in only one place.

    On the AC side, you need to bond neutral to ground - in only one place.



    Tie all the metal parts together with wire. That's the equipment ground. Connect that equipment ground to however many ground rods you want, in as many places as you want.

    BUT tie AC neutral to that grounding system in only one place - the main electrical service panel.

    And, to get back to your original question - if you can't isolate neutral from ground in the generator - then isolate the generator from ground.
  • BB.BB. Super Moderators, Administrators Posts: 30,520 admin
    Re: Another Inverter Question
    dwh wrote: »
    And, to get back to your original question - if you can't isolate neutral from ground in the generator - then isolate the generator from ground.
    And here is where it gets complicated... Ideally, then only connect the L1/L2 and Neutral wires, and no frame ground, no "green wire" ground though the extension cord.

    That should give you no ground loops.

    But, now the generator becomes potentially unsafe... if, for example, the neutral wire back to the e-panel breaks, the chassis of the generator (because its local neutral and green wire are connected) still could be "hot" (because there is no neutral back to ground reference)... Your 240 VAC loads would still work OK, but your split phase 120 VAC loads probably would not (one would be near zero volts, the other near 240 VAC--depending on how the loads are distributed between the two split phases from the e-panel).

    This would also energize the genset frame with respect to the earth/safety ground--Not a good idea if the generator is outside on wet ground and you are wet from the rain storm.

    There are things you could do to help keep it safe(r)--Convert the genset from rain, use a thick rubber mat to keep your feet out of water, even install a 240 VAC bulb between the gen frame and safety ground (if lighted--then there is a shock hazard)--but none of these are guarantees (kids around genset, metal poles from rain tent, bulb burns out, etc.)...

    Going back inside the wiring panel for the genset and lifting the ground/neutral bond (cheap)--OR--getting an isolation transformer (not cheap) and installing between the generator and the home transfer switch are the two ways I can think to make it "safe:" (and grounding the frame of the genset to earth/safety ground).

    This is the old problem... 99 times out of a hundred--just connect the stuff together and all is fine. No shocks, no burned out safety grounds or equipment.

    And that 1 time out of a hundred--something does go wrong (two DC grounds--one at the battery and a second one at some sort of device--such as a DC powered ham radio, chassis grounded, and a grounded antenna cable, etc.).

    I am not trying to scare you--it is just saying that it is important to understand the reasoning behind the rules/requirements. And why something "simple" -- like grounding -- creates so much confusion and consternation.

    I don't know you or your installation,. while providing information from many miles away--and I will "default" to giving the "safest" advise I can (and like DWH too and everyone else--I am sure).

    Too many "ground/neutral/negative bus connections"--You can end up with hazardous ground loops (damaged equipment, overheated wiring if DC currents are impressed on your AC system).

    Too few safety grounds--Can end up with electrified equipment (boxes, gensets, etc.) if something fails/breaks....

    Do it right--and you should end up with a system that works well, and single points of failures will "fail safely".

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • bryanlbryanl Solar Expert Posts: 175 ✭✭✭✭✭
    Re: Another Inverter Question

    Some of the issues that confuse this issue include the definition of 'ground'. There are at least three different concepts. Here is how I understand things from reading various sources.

    One is the earth ground. There really should be only one of these at each site unless great care is used to design a ground plane connecting more than one. The earth ground is usually a rod driven into the earth at the service entrance (meter). This serves as a base reference for the grid power, a safety for such things as lightning strikes, as a noise prevention mechanism, and so on. This ground used to be used as one side of the electric circuit but that role has been greatly reduced in modern power distribution systems. Modern practice is to use actual wires rather than plumbing to connect to earth grounds.

    A second concept is the equipment or frame ground. The purpose of this ground is to make sure that all exposed conductive materials are all at the same electrical potential. This reduces the risk of unintended electrical shock. This ground is usually connected to the earth ground at the service entrance -- Again, only one connection point. Wires for this are usually green or bare. Any currents between things at this level are considered leaks and should trigger GFI protection circuits.

    The third concept is the power reference. This is the power delivery lead that is used to measure the voltage to the other leads. It is usually called the 'neutral' lead and colored white. In grid tie or larger power systems, this lead is connected with the frame ground. Again, this connection occurs at only one point and that point is the service entrance.

    With modern gensets or inverters, especially those that have plugs for power connection and provide less than 5 kW, the power leads are usually isolated from any ground and which one serves the function of neutral is defined only by its being attached to the modern polarized AC plug neutral connector. In portable applications (e.g. RV), there is no need for an earth ground connection and the frame ground is connected via the 3 wire power cords (110vAC).

    If the genset gets above about 5 kW, the induced currents can be large enough to be of concern so code requires these to connect the neutral to the frame ground. When you get into these power levels with either inverters or gensets, you should have a properly wired transfer switch that will make sure the proper grounding connections are made at the proper location.

    I'd think that the earth ground being bonded to frame ground would be a given in a grid tie situation. The job for the transfer switch is to isolate the power leads so only the desired power source is connected to the loads and to connect the desired power source neutral to the frame ground if that power source was of sufficient size to require it.

    If you have an inverter that has problems connecting the neutral to frame ground because the frame ground is shared with DC input power leads, then you will need to do some external isolation as suggested above.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Another Inverter Question

    would you guys care to elaborate this down to a definition or definitions we could use in the new glossary area? this would be an elaborate definition(s) with many ins and outs to it i would think. i don't want you to hijack this one just for the definitions sake, but post something over there in the other thread that we can kick around.
    http://forum.solar-electric.com/showthread.php?p=40522#post40522
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: Another Inverter Question
    niel wrote: »
    would you guys care to elaborate this down to a definition or definitions we could use in the new glossary area? this would be an elaborate definition(s) with many ins and outs to it i would think. i don't want you to hijack this one just for the definitions sake, but post something over there in the other thread that we can kick around.
    http://forum.solar-electric.com/showthread.php?p=40522#post40522


    I think he's got me beat on the definition part of it. I mostly try to answer installation specific questions.
  • WilisWilis Solar Expert Posts: 84 ✭✭✭✭
    Re: Another Inverter Question

    Thanks to everyone,

    I will remove the bond wire between the equipment ground and the AC neutral in the e-panel. I have run separate AC circuits for my solar and my house AC. I have ran boxes to each area I want solar AC. I just plug into the different boxes as I have enough solar to run my freezer, refrigerator, TV, etc. My appliances are just standard ones, so they require more energy and my system will not run everything 24/7. Right now I am running the freeze and the TV 24/7 for the hours required and the batteries never go below 85%. I can do a grid charge if weather is cloudy for too many days. All this is just an experiment and I have learned a lot. I will use equipment ground to the AC distribution box case (this box is separate from the house 200 amp box), but keep the 240v AC netural grounded to the house grounding.
    Thanks Bill for the information about ham radio. I do have a separate ground rod for the radio equipment. I had not though about the trouble that might cause. So far that has worked with the house AC grounding, but will take caution when I try the solar to run this equipment. I will check with my meter when I try to charge the batteries from the gen. before I trip the breaker and energize the inverter from the gen. Most likely I will just run and extension cord and not run through the house AC wires.
    I have 2 out buildings that have AC ground rods, 2 radio towers that are grounded, all this solar grounds, AC house ground, ham radio equipment ground rod, if I don’t have a ground problem I will wonder. Always afraid of lighting in the summer and if I get a direct strike most likely none of the ground will save very much. I will keep reading the forum and I am sure others will have questions about grounding. Thanks again to everyone for the info. Wil
Sign In or Register to comment.