solar grid tie hybrid questions

[charles2,david000k]

They are trying to help you. If you want a legal grid tie solar pv system then you have to spend the money to get it.You can't do it on your small budget. A UL listed grid tie inverter (SMA, SolarEdge ABB, Fronius, Solectra) to name a few, will cost you at least $1000 and should be approved by your POCO.

Using non UL listed solar equipment (purchased off of fleabay) will end up getting you in trouble with your POCO or worse causing a fire.

I have been in contact with my local and state power provider green power program and from what I can tell there is a window for 2016 where you dont need sertain thing now what all these are I am currently working out with TVA and VEC but I will also check with my county court house for permet information. As of 2014 and 2015 they didnt even have a standard permate system set up yet. It was more of pull a $35 remodle permate and have the inspector check it out but last I checked he hated even coming out to look at the systems and faild every one the first time no mater what even if a licencs installer did the job.

[SunEagle]

I have been in contact with my local and state power provider green power program and from what I can tell there is a window for 2016 where you dont need sertain thing now what all these are I am currently working out with TVA and VEC but I will also check with my county court house for permet information. As of 2014 and 2015 they didnt even have a standard permate system set up yet. It was more of pull a $35 remodle permate and have the inspector check it out but last I checked he hated even coming out to look at the systems and faild every one the first time no mater what even if a licencs installer did the job.

I understand your frustration with your local inspectors and POCO. Sometimes it is an uphill battle that seems very hard to win. I just want you to think about installing a "safe" and legal pv grid tie system.

The crooks on fleabay don't care if their product fails after you have been purchased. And the US laws do not stop them from selling these items. The best case is that those plug in inverters just stop working. Worst case is for them to short out and cause a fire.

Please think about what we are trying to tell you and hopefully you do not get hurt or worse.

[charles2,david000k]

Going to grid tie is the right way to get the most value out of the panels you own. There are relatively inexpensive *legal* grid-tie microinverters out there. For example, this would work with your panels, and would be under your budget before adding in cabling, a disconnect, and over current protection. (Buy 1 per panel)

http://www.ebay.com/itm/New-Enecsys-...-/181931035581

It is not a good idea to try and go grid tie without getting the proper permits and approvals. If your power company finds you backfeeding into the grid without approval, you could find yourself *charged* for that energy, instead of receiving credit. At worst, they could disconnect you, although I'm not sure there are any true stories out there of that actually happening.

The permit process should not be hard, but may take you some time. You might be able to find examples of others near you who have done it, and use their designs as a template.

I like it but what about the ac output cord. It looks like it attaches to a main cord?

[charles2,david000k]

Going to grid tie is the right way to get the most value out of the panels you own. There are relatively inexpensive *legal* grid-tie microinverters out there. For example, this would work with your panels, and would be under your budget before adding in cabling, a disconnect, and over current protection. (Buy 1 per panel)

http://www.ebay.com/itm/New-Enecsys-...-/181931035581

It is not a good idea to try and go grid tie without getting the proper permits and approvals. If your power company finds you backfeeding into the grid without approval, you could find yourself *charged* for that energy, instead of receiving credit. At worst, they could disconnect you, although I'm not sure there are any true stories out there of that actually happening.

The permit process should not be hard, but may take you some time. You might be able to find examples of others near you who have done it, and use their designs as a template.

Ok I found the trunk cable and have a few question.
It looks to be pretty simple three wire red hot/black hot/green for ground?
Grounding the inverter. Dose it ground by the metal to metal contact to the panels or does it require a separate ground? Panels are grounded with 2 Awg bar wire to its own dedicated grounding rod for lightning protection.
Is it UL certified? I didn't see a UL mark on it.

[sensij]

It bears a cTUVus mark, which is an OSHA recognized third party test lab (Nationally Recognized Testing Laboratory) and usually sufficient to comply with code requirements. It is also on the approved list of inverters for the California Solar Initiative. It is Ebay, so there is always a chance they are knock-offs, but the price looks about right for a legitimate model (I think they are discontinued).

Since your panels are already grounded, if you connect the ground from the trunk cable to your house ground, it should be OK. Your grounding plans will typically be part of your permit submittal, and your AHJ will let you know if it doesn't meet their requirements. If you haven't already, it would be a good idea to bond your array's ground electrode to your main electrode, but it may not be required.

The red and black from the trunk cable will need to wire into a dedicated 240 V breaker (two pole) on a subpanel or your main panel. There are rules about what size breaker is required, how much backfeed the panel can support, and where the breaker can be positioned on the panel.

[charles2,david000k]

It bears a cTUVus mark, which is an OSHA recognized third party test lab (Nationally Recognized Testing Laboratory) and usually sufficient to comply with code requirements. It is also on the approved list of inverters for the California Solar Initiative. It is Ebay, so there is always a chance they are knock-offs, but the price looks about right for a legitimate model (I think they are discontinued).

Since your panels are already grounded, if you connect the ground from the trunk cable to your house ground, it should be OK. Your grounding plans will typically be part of your permit submittal, and your AHJ will let you know if it doesn't meet their requirements. If you haven't already, it would be a good idea to bond your array's ground electrode to your main electrode, but it may not be required.

The red and black from the trunk cable will need to wire into a dedicated 240 V breaker (two pole) on a subpanel or your main panel. There are rules about what size breaker is required, how much backfeed the panel can support, and where the breaker can be positioned on the panel.

Ok thank you I just got part of the application from the state and it is asking this stuff so I will be back

[jflorey2]

You guys said drop the off grid inverter and go with a grid tie it gets rid of the batteries and all the extra dc wiring. Well that's what I am trying to do for the time being on a budget of $470.

With $470 you can buy 3 Enphase inverters with some wiring devices; that gives you about 750 watts of grid tie. You'll still need inspections (likely 2) and utility signoff.

I thought pure sine wave was two legs of 120 and that inverter is rated from 190 Vac to 260 Vac output.

"Pure sine wave" has to do with wave shape and harmonic content and has nothing to do with voltage. You can have a 12V 400Hz pure sine wave as easily as a 240V 60hz pure sine wave.

[inetdog]

....Well that's what I am trying to do for the time being on a budget of $470. I thought pure sine wave was two legs of 120 and that inverter is rated from 190 Vac to 260 Vac output. I like you! You tick me off and push me to learn more every day but you gonna keep riding me at least buy me a drink and some lipstick!

Normal (in the US) power from POCO is two "hot" legs, each 120V AC from ground but in exactly opposite phasing. When one AC waveform is at +120V the other hot lead is at -120V. The result is that the voltage between them is 240V AC.
Since the same amount of power requires less current at a higher voltage, the micros, and most string inverters, are designed to connect between the two hot wires.
Off grid inverters can more cheaply supply the 120V most people need most by just providing one 120V output. Then if you really need 240 you have use a transformer or stack two 120v inverters with the appropriate interconnections to make them play well together.

[charles2,david000k]

With $470 you can buy 3 Enphase inverters with some wiring devices; that gives you about 750 watts of grid tie. You'll still need inspections (likely 2) and utility signoff.


"Pure sine wave" has to do with wave shape and harmonic content and has nothing to do with voltage. You can have a 12V 400Hz pure sine wave as easily as a 240V 60hz pure sine wave.

I wish it was easy as them just signing off on the system its $250 for them to look at my design and $500 for them to slap a meter in the socket I got my own meter from their supplier for $70 bucks new and they told me to return it. Solar Solutions of chattanooga said they negotiate cost with the power company but I have no clue on even how to start negotiations.

[charles2,david000k]

Normal (in the US) power from POCO is two "hot" legs, each 120V AC from ground but in exactly opposite phasing. When one AC waveform is at +120V the other hot lead is at -120V. The result is that the voltage between them is 240V AC.
Since the same amount of power requires less current at a higher voltage, the micros, and most string inverters, are designed to connect between the two hot wires.
Off grid inverters can more cheaply supply the 120V most people need most by just providing one 120V output. Then if you really need 240 you have use a transformer or stack two 120v inverters with the appropriate interconnections to make them play well together.

gotcha AC alternating current it is just move back and forth pure sin wave is AC pure sin wave is just a short way of saying it curve off smoothly and not a jump up like square wave and mod square wave square wave would jump straight up to 120V sit there before dropping straight back off. With square wave I would suspect a small micro gap in waves right or would it plummet straight from + to -

Sorry been reading and just wanted to make sure I got it right.

[inetdog]

gotcha AC alternating current it is just move back and forth pure sin wave is AC pure sin wave is just a short way of saying it curve off smoothly and not a jump up like square wave and mod square wave square wave would jump straight up to 120V sit there before dropping straight back off. With square wave I would suspect a small micro gap in waves right or would it plummet straight from + to -

Sorry been reading and just wanted to make sure I got it right.

You got it right!
Square Wave just alternates from + for 1/2 cycle to - for 1/2 cycle. So called Modified Square Wave (which some people prefer to call Modified Sine Wave, which it is not really close to at all) is at zero for 1/4 cycle, then + for 1/4 cycle, then zero for 1/4 cycle and finally - for 1/4 cycle. The peak voltage is higher for MSW, and the edges are just as steep and there are twice as many of them.

[jflorey2]

I wish it was easy as them just signing off on the system its $250 for them to look at my design and $500 for them to slap a meter in the socket

Right. Inspections cost money; it's time they have to spend reviewing your design. That means it won't be free.

I got my own meter from their supplier for $70 bucks new and they told me to return it. Solar Solutions of chattanooga said they negotiate cost with the power company but I have no clue on even how to start negotiations.

That's why going through an experienced installer will save you time, effort and money.

[jflorey2]

Square Wave just alternates from + for 1/2 cycle to - for 1/2 cycle. So called Modified Square Wave (which some people prefer to call Modified Sine Wave, which it is not really close to at all) is at zero for 1/4 cycle, then + for 1/4 cycle, then zero for 1/4 cycle and finally - for 1/4 cycle. The peak voltage is higher for MSW, and the edges are just as steep and there are twice as many of them.

And then there's stepped sine, which the old Trace SW series used. A lot more transitions and a lot closer to a true sine wave - but still tons of harmonic content.