Another P&P Vendor - Can plug and play work in the US?

I am interested in Plugged Solar concept but reviews are bad.

http://youtu.be/82kpdH9PwVo

Also, this company has put a restriction on their youtube video posting so that people cannot freely comment about the product. Is this a good practice or red flag or Scam? This is a Houston based company (ensuprasolar.com).

Please share your thoughts!!
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Comments

  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    There has been quite a number of discussions of various "plug and play" solar installs on this forum.
    Bottom line: they are not safe or legal because of the basic fault in the install; no dedicated feed line that guarantees the wiring can not be overloaded.

    Also, without the cooperation of the utility there can be other troubles including incorrect billing (they don't know you are selling back to the grid, so if you do achieve surplus production you may actually be charged for it) and if they decide you have an illegal install they may disconnect your power.

    Add to that if anything causes a fire in the house an insurance company may use the illegal GT install as an excuse to not pay.

    Plug-n-play inverters: don't touch them with a 40 foot utility pole.
  • BB.BB. Posts: 27,698Super Moderators admin
    If you want to see the mounting of 4 panels on a rack with Enphase inverters--This video is pretty good to a point:

    http://www.youtube.com/watch?v=xFAS5Eoahcg

    That point being tying grounds and connecting the AC power from the inverters to the breaker box/meter/etc... At that point, nothing is to code (they may have done that just to show the basic wiring).

    The video you type about is European, not US--So code requirements are different... And what may be "legal" in one location is not legal elsewhere.

    In the US, true "Plug and Play" will never be legal due to the way our safety codes work (unless somebody literally wires up a dedicated outlet to the roof when the home if first built) and there is a utility agreement already in place (plus, most locations will require a building permit+inspections).

    It is not rocket science--But a trades person that knows their job can make it look very simple. Somebody that does not know what they are doing can start a fire:

    Panel Fire Question - Northern Arizona Wind and Sun

    Some of these people are very slick--And will convince people (including inspectors) that they know what they are doing.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • sfeed001sfeed001 Posts: 2Registered Users
    BB. wrote: »
    If you want to see the mounting of 4 panels on a rack with Enphase inverters--This video is pretty good to a point:

    http://www.youtube.com/watch?v=xFAS5Eoahcg

    That point being tying grounds and connecting the AC power from the inverters to the breaker box/meter/etc... At that point, nothing its to code (they may have done that just to show the basic wiring).

    The video you type about is European, not US--So code requirements are different... And what may be "legal" in one location is not legal elsewhere.

    In the US, true "Plug and Play" will never be legal due to the way our safety codes work (unless somebody literally wires up a dedicated outlet to the roof when the home if first built) and there is a utility agreement already in place (plus, most locations will require a building permit+inspections).

    It is not rocket science--But a trades person that knows their job can make it look very simple. Somebody that does not know what they are doing can start a fire:

    Panel Fire Question - Northern Arizona Wind and Sun

    Some of these people are very slick--And will convince people (including inspectors) that they know what they are doing.

    -Bill

    Thanks guys!! I find several other bad reviews about this company in other forums too. Outrageous...Ensupra Solar is indulge in so many illegal activity. I doubt this business will survive for long. I really feel bad for those who already got trapped.

    Thanks for the warning once again.

    God bless..
  • NorthforkerNorthforker Posts: 15Registered Users
    Suppose one had a dedicated outlet alone on a circuit and wired directly to the service?
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Suppose one had a dedicated outlet alone on a circuit and wired directly to the service?

    Remove the plug & outlet and you have the required "hard wired" connection. Sort of eliminates the whole concept of plug-n-play, doesn't it?

    Then you'd need the proper permits and permissions.

    In other words, do it right instead of doing it wrong and there is no problem.
  • icarusicarus Posts: 5,108Solar Expert ✭✭✭✭
    Haven't we he it conversation, again, and again and again?!

    Plug nd play in errors are NOT legal or permitted in N. America. They maye legal to sell, but they re not legal to install grid tie.

    Tony
  • BB.BB. Posts: 27,698Super Moderators admin
    And there are many people here in the US (and elsewhere) that are doing it.

    How many problems? Don't know. Many of the plug&play systems seem to be not very reliably designed and the inverters tend to run/hot/fail early--And/or do not even work out of the box.

    The problem with GT Solar is you cannot operate a GT Inverter on "...a dedicated outlet alone on a circuit and wired directly to the service."

    The true GT AC Inverter needs the utility power to act like a "giant AC battery"-- Power needs to flow in both directions (to and from the utility) for the GT inverter to operate as intended.

    There are systems available that can connect a solar array to an AC inverter and output 120 VAC (SMA has a new pure GT inverter that can give you something like 10 amps of 120 (or 240?) VAC)...

    However, most AC appliances assume the AC power is constant... Having the AC power "go away" when a cloud passes overhead or a bird flies over or when the AC appliances has a surge current (like a washer turning on)... etc...

    Most of us use AC power when needed... To have AC power that can turn on/off at any time--much less useful power.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Most people "get away with it" because they have one 200 Watt plugged-in inverter which their household consumption "swallows" without notice.

    Trouble is they think it would be a good way to expand. So they buy another, and another, and another .... and plug them all in to the same outlet. So they end up with a piece of 14 AWG wire in the wall which can handle 20 Amps max but is now connected to 15 Amps from the main service + however many Amps are available from all the GTI's connected to it. Three of them @ 1.6 Amps each and you're in trouble with over-current potential.

    And you might even generate enough that it shows up at the meter, which is another problem.

    To say nothing of what the consequences are if there's a fire and an illegal grid-tie is found in the wreckage; cause or not it's reason enough for the insurance company to avoid paying.

    *This broken record will now skip back to the beginning and play over.*
  • NorthforkerNorthforker Posts: 15Registered Users
    Remove the plug & outlet and you have the required "hard wired" connection. Sort of eliminates the whole concept of plug-n-play, doesn't it?

    Then you'd need the proper permits and permissions.

    In other words, do it right instead of doing it wrong and there is no problem.

    Agreed, Thanks for the clarification
  • bigbillsdbigbillsd Posts: 2Registered Users
    I am going to put this setup thru the paces. I contacted ensupra and they sent me lots of PDF's to bring the building department and to my local San Diego Gas & Electric company to see if they will allow this before I buy that Plug and Play 1.7 KW system for $3000.OO on Amazon. I already have a dedicated 20 amp circuit that was put in during a remodel 8 years ago. I calculated that without any government rebates and only doing away with any KWH over the 300 KWH threshold when it jumps to 28 cents a KWH here in San Diego, the ROI is less than 3 years. Anything less than 5 years is a great deal in my book.

    Off to the battles with the building department.

    BTW. I did find the energy.gov site that started the plug and play solar movement back in 2010. There is not much there, but the Feds want something like this to work.
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Maybe some people do want it to work, but they can't change the physics of it no matter what.

    Everything works fine as long as you do it right. Being able to plug inverter power into any available outlet simply makes it too easy to do it wrong. Just because it passes inspection upon install doesn't mean it will stay that way, as pulling out one plug and sticking it in again somewhere else (more accurately adding several more) is all too easy to do compared to actually hard wiring an inverter in place.

    You can do an improper hard wire install too. Having power at the end of a plug simply makes it easier to do it wrong. No amount of wishful thinking on behalf of manufacturers, consumers, or government agencies can change that. Not safe. End of story.

    With the increasing anti-solar attitudes of utilities you will see more of these install done no matter what. When they make the rules too onerous people are want to skip the rules entirely, and plug-n-play facilitates that.
  • bigbillsdbigbillsd Posts: 2Registered Users
    If my building inspector will allow it I am going to do it and I personally think everyone should.

    I found a US department of energy site from 2010 giving grants to people to create Plug and Play Solar (PV). Seems a few years later, someone has done it. http://energy.gov/articles/going-sol...ug-and-play-pv Yes can people screw it up, can you run over folks at a bus stop? Have you?
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    For your analogy to be valid the bus stop would have to be in the middle of the road and the people standing in it invisible.

    The problem is that the average person has no understanding of electricity beyond "plug it in, turn it on, and it works". The would have no idea they are getting in to trouble by plugging in a power bar and filling it full of plug-in inverters. These things make it too easy for people to create the hazard without their having any knowledge that there is a risk. It is very much like cube taps, and I can tell you a lot of fires have been started by multiplying out the number of outlets available and loading them up.

    As far as having a dedicated line for the plug-n-play inverter goes, as has been said before you may just as well hard wire it which removes the whole point of having the plug. Perhaps if they modified the Enphase system so that the permit could be drawn for a total of 17 units on a dedicated 20 Amp line and utilized their special connectors so that the homeowner could add as funds were available that would be different.

    If these things are ever allowed it will only demonstrate that you can't fix stupid, but you can make it legal.
  • solar_davesolar_dave Posts: 2,337Solar Expert ✭✭✭✭
    bigbillsd wrote: »
    If my building inspector will allow it I am going to do it and I personally think everyone should.

    I found a US department of energy site from 2010 giving grants to people to create Plug and Play Solar (PV). Seems a few years later, someone has done it. http://energy.gov/articles/going-sol...ug-and-play-pv Yes can people screw it up, can you run over folks at a bus stop? Have you?

    Anyone could have done some similar any time, and in fact the plug and play has been on eBay for years. But is it legal? No, the utility gets to say how it is receiving power as it owns the grid and the AHJ gets to say how it is connected.

    Good luck on your quest with the AHJ.
  • SkiDoo55SkiDoo55 Posts: 414Solar Expert ✭✭✭
    The thing he is not reading in the paper is that it will be plugged into a PV Ready circuit that has detection devices that will automatically configure it and the grid.
    I bet he doesn't have that for what is being done. Here is quote from the paper he referenced

    "Plug-and-play PV systems could be installed without special training or tools, and simply plugged into a PV-ready circuit, through which an automatic detection system would initiate communication between the solar energy system and the utility."
    GT3.8 w/4600W Trina 230W, TX5000 w/5000W ET-250W, XW4024 w/1500W ET-250W, 4 L16, 5500W Gen. (never had to use) Yet!!
  • inetdoginetdog Posts: 3,121Solar Expert ✭✭✭✭
    SkiDoo55 wrote: »
    The thing he is not reading in the paper is that it will be plugged into a PV Ready circuit that has detection devices that will automatically configure it and the grid.
    I bet he doesn't have that for what is being done. Here is quote from the paper he referenced

    "Plug-and-play PV systems could be installed without special training or tools, and simply plugged into a PV-ready circuit, through which an automatic detection system would initiate communication between the solar energy system and the utility."

    I think that the PV-ready circuit is primarily a dedicated circuit with no other place to which loads could be connected, and the automatic detection system is likely to be part of the inverter device. Commonly known as anti-islanding circuitry.
    Unless perhaps there is also a special breaker that communicates over the power line to tell the inverter what amperage the circuit wiring will allow. :-)
    SMA SB 3000, old BP panels.
  • BB.BB. Posts: 27,698Super Moderators admin
    It sounds a bit like the next generation of UPS will have the the ability to communicate directly back to the utility (or to the electric meter, then to the utility).

    As GT Solar (and other small local generators) become more common, the Utilities what to know that these devices are out there so they can better model and predict their total loads. I would also think that the utility wants the ability to control the GT inverters too (ability to turn off when there is too much generation going on, possibly programming PF to lower values (like 0.80 or less PF) to better support the "real loads" on the utility's grid). And to allow automatic billing based on new net metering/tarifs for GT inverters.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • inetdoginetdog Posts: 3,121Solar Expert ✭✭✭✭
    BB. wrote: »
    It sounds a bit like the next generation of UPS will have the the ability to communicate directly back to the utility (or to the electric meter, then to the utility).
    Over on the MH forum, a commercial UPS was described that actually fed power back to the supply side during scheduled full load tests if the load at the time was not enough to drive the UPS to full output. Not sure exactly how that was arranged with POCO, but a directional "network protection" relay was used so that the output went only to other local loads that normally did not run from the UPS rather than ever feeding back to POCO.
    The problem that started that thread was that at the time of the automatic test the other connected loads were low enough that the protection relay tripped, cutting off POCO power to the whole system. That left only UPS-fed equipment with power. :-)

    Communicating with POCO and having a backfeed agreement in place would be the next step in that evolution.
    SMA SB 3000, old BP panels.
  • igor1960igor1960 Posts: 85Solar Expert ✭✭✭✭
    I'm confused. Why do you need dedicated line for Plug And Play? What could go wrong if I have inverter(s) producing 2-3amps on one 15amp line?
    The only reqirements that if the line allow plug and play inverters installed then the wire gauge, outlets, switches should be for 2 times the current on circuit breaker.
    If we fullfill that then we possibly have just 5 scenarios:

    OK, assuming I have 5 outlets occupied by 5 plug and play inverters each producing 2amps => ok, this is negative 10AMP on the circuit breaker.
    1. Now, I'm placing one 200watts bulb into 6th outlet: that bulb obviously will "eat" around 2AMP (2*110=~200wt) and therefore I would have negative (10-2)=8AMP on the circuit breaker, as full current to bulb would be satisfied by partial 5 plug and play inverters.
    2. Now, assume the situation where I connected 1kwt (1000wt) bulb (or other big consumer) to 6th outlet: in this case that consumer will "eat" around 10AMP (10*110=~1000wt) and there will be no current on the circuit breaker, while the full current to that consuter would be satisfied by full production power of 5 plug and play inverters.
    3. Even the "worse" someone "stupid" connects 2kwt (2000wt) bulb (or other big consumer) to 6th outlet: in this case that consumer will "eat" around 20AMP (20*110=~1000wt) and there will be positive 20AMP-10AMP=10AMP current on the circuit breaker, while the full current to that consumer wouldn't be satisfied by full production power of 5 plug and play inverters. The problem will be delayed until the sun starts to set down, inverters production will drop to around 5AMP and then circuit breaker will receive current of 20AMP-5AMP=15AMP at this moment circuit breaker will disconect the line. Obvoisly, there will be 20AMP current on outlet to that "big" consumer, but as I said before "the wire gauge, outlets, switches and etc." are to satisfy that load;
    4. The last scenario: due to unusual sun activity and/or "stupid" user connecting 2-3 more plug and play inverters to the same circuit: we get sum of production from all those N inverters above 15AMP. So, what? Our circuit breaker will just disconnect as negative 15AMP is going through it...

    So, what is so "dramatic" in all of those scenarios? There will be no fire or anything like that.

    Did you ever unintensionally overload any circuit at home by turning on extra iron, tea cattle and etc.? Did your house got fire because of that?

    So, "knowledgeable" people, please explain!

    Just build or use existing 30AMP circuit line with 30AMP outlets, switches and etc and install 15AMP breaker on it or;
    build or use existing 20AMP circuit line with 20AMP outlets, switches and etc and install 10AMP breaker on it or;
    build or use existing 15AMP circuit line with 15AMP outlets, switches and etc and install 7.5AMP breaker if you know the way on how to do this....
  • BB.BB. Posts: 27,698Super Moderators admin
    Basically, it is the old multiple power source problem in any engineering design.

    You have a single 15 amp circuit, and there is no more than 15 amps in a circuit due to down stream loads.

    Put 15 amp breaker up stream, and (legally) 12 amps in the wiring mid stream. And you have 15+12 amps = 27 amps down stream for the last outlet in the line.

    The wiring to that last outlet has some fixed resistance. One of the power equations is Power=I2*R... The available heating per foot of 14 awg wire is:

    (27 amps)2 / (12 amps legal max max)2 = 5.0625 times more available current

    So, that downstream load has 5x as much available heating due to I2R losses. That is always the problem with distributed power circuits (N+1 redundancy, etc.)... Is making sure that you cannot have excess current/energy anywhere in your circuitry.

    That is way, I believe, that you will never have "Legal" Plug and Play GT Inverters in the US/North America.

    To do this safely, you need dedicated circuits for GT Inverters to connect to the AC Mains. For a new home, running an additional couple of 240 VAC circuits up to the roof is not a big deal... It is not even that expensive to do after the fact for older homes (I did this for my 75 year old home).

    Where it gets expensive if the requirements for the Main AC Panel where the GT inverter meets the grid. There is a set of rules about how much power can be "injected" in the house panel. And it can take $4,000 (plus or minus) to up grade a panel for an older home (more or less, usually a 125 am minimum AC mains panel for a ~3-4 kW solar array).

    There are places where you will find a single "circuit" is wired with two sources. In the UK they use "Ring Circuits" where you have basically a set of power wires that run around the entire room (or home) and comes back to the main panel.

    For example, you can feed 10-32 amp fuse/breaker into each direction of the ring (I thought it was a pair of ~13 amp fuses, but it appears it was a single ~32 amp fuse feeding the whole ring)... And if you plug into the ring at any point, no more than (for example) rated current is available at each point through downstream and upside wiring. However, the UK requires a fuse in the plug (usually 13 amps) so that the appliance does not see >13 amps in an overload/shorted situation.

    This was a "quick fix" for use during/after WWII when there was lots of reconstruction and shortages of copper. However, Ring Circuits do have there own issues and have not been adopted in very many other locations.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Posts: 27,698Super Moderators admin
    igor1960 wrote: »
    Just build or use existing 30AMP circuit line with 30AMP outlets, switches and etc and install 15AMP breaker on it or;
    build or use existing 20AMP circuit line with 20AMP outlets, switches and etc and install 10AMP breaker on it or;
    build or use existing 15AMP circuit line with 15AMP outlets, switches and etc and install 7.5AMP breaker if you know the way on how to do this....

    You certainly can do this--But again there is the issue of source over current protection and how to "know" that you have a limited number of outlets available to "inject power" into the power system. Remember that the NEC only allows you to "permanently" install loads at 80% of the wire/breaker wiring. 15 amp fuse/wiring should only be loaded/operated to 80% of rated power--So you need to ensure that any of your downstream loads/power injection meet the 80% maximum requirement (if you load fuses/breakers over 80% of circuit rating).

    And--given the issue of an unknown number of "mixed use outlets" and distributed wiring between circuits and how to limit the maximum current between breaker/outlets/etc.

    Copper is not cheap, and installing derated outlets plus local fuse/breaker--Just adds cost for no immediate useful gain (at time of construction vs installing solar sometime in the unknown future).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    to put this more simply you may get a branch circuit to be technically safe to use with the added extra current from a solar setup, but the nature of plugnplay would not differentiate between outlets on that circuit or other outlets on other circuits and that would be unsafe. there would be no way to prevent you to plug into a different circuit or in the future have an outlet from a different circuit put in within reach. hard wiring makes it dedicated to that circuit.
  • igor1960igor1960 Posts: 85Solar Expert ✭✭✭✭
    Thanx for the responces. However, technically I'm not satisfied with your answers... None of you presented scenario, when the circuit with twice low circuit breaker then rated wires, outlets and etc. is really technically vulnerable. As to possibility of plugin in plugin inverter into circuit other then discussed -- no one talks about that, as this issue could be easily resolved by just replacing receptacle and/or connecting directly...

    BB: I'm completely lost in what you are saying. Are you saying that, when I connect 2000 watt consumer sitting on last outlet of the line having positive 20AMP current and 1000 watt inverters having 10AMP to 0AMP negative current, and as the result I'll get more then 20AMP positive current somewhere in the circuit? Excuse me and please explain how?!!! The highest positive current on this circuit would be 20AMP positive, when my inverters are not producing anything (which is equal to not connected inverters at all and/or circuit with no inverters)...
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    if you think you know better than us or the nec then do what you want. putting 3a of solar to a 15a circuit does not amount to 12a net as it adds to the total current available as 15a (from cb) + 3a solar for 18a available and is too much for the wiring. this can be made to work if the circuit wiring was #12 which is rated for 20a. fine, but to prevent you or any other person from putting the extra current from the solar to any other circuit that does not have the ability to handle the extra then it must be hard wired as plugnplay presents a hazard to any other circuits. this same pnp inverter with pv is also portable enough that one might lend or sell it to somebody else that it will be placed onto circuits not able to safely handle it. hard wiring insures idiots don't put it into an unsafe condition elsewhere. that means pnp is unsafe.

    case closed.
  • igor1960igor1960 Posts: 85Solar Expert ✭✭✭✭
    Niel: Your answer was rude... With all due respect, but:
    niel wrote: »
    putting 3a of solar to a 15a circuit does not amount to 12a net as it adds to the total current available as 15a (from cb) + 3a solar for 18a available and is too much for the wiring

    Wrong! 15A downstream and 3A upstream exactly in sync. (and P&P inverter does it) is exactly 12A downstream

    However, even if you are right: as I said 15a CB would be tripped at 15A => however I've mentioned that our circuit has 30AMP gauge wires, outletrs and etc., so 18A would not damage it...

    And then to everybody: Are we talking about "unsafe" receptacle? If yes, then OK, I agree: better to come up with $2 new electrical outlet/receptacle/plug design/implementation/standard, then to kill idea of Plug and Play, just because current receptacle allows to connect it anywhere. But isn't this a small issue?!
  • BB.BB. Posts: 27,698Super Moderators admin
    I am not sure what else to say... If you have an outlet designated to connect to a 15 amp circuit... The wiring, breaker, outlet, and even the appliance cord (or extension cord) are designed for 15 amps * 0.80 NEC derating = 12 amp continuous power.

    If you start adding additional sources of power to the "branch circuit" (a GT Inverter), then you will have an additional source of current and, it is possible, to pick and choose a combination of "appliances" (including GT type) that will exceed the ratings of the "system".

    You can exceed the ratings of a system by a little amount (20% would be 3 amps for a 15 amp circuit--Or, roughly a 330 Watt GT inverter+panel/array)--Or you can exceed it by a lot (~2x).

    Resident A may plug only GT inverter into that outlet... And Resident B may plug in an electric heater, stereo, hair drier, TV, halogen lighting, etc. in the bedroom.

    It is possible that A will be happy. And B will have problems with night/bad weather popping a breaker, and on a cold/clear winter morning needing to call the fire department.

    Add that solar panels need to be mounted outside--They need to be affixed so that they don't blow away and cause damage (and pull out AC/DC wiring). If there is a lightning strike there is ~6 AWG cable from the frame to a dedicated safety ground (preferably run down the outside of building to a ground rod/cold water pipe at the edge of the foundation), as opposed to bringing in the lightning into A or B's bedrooms, etc.

    If you want to use 4x as much copper in your power lines/outlets, use 1/2 size circuit breakers, and put a warning on the wall outlets what the maximum rated daytime/nighttime loads/power sources, and include 30' of 6 awg copper cabling from the array frame/metal work to reach the ground, with a 8-10' ground stake+clamp (plus a warning to call 811 before you dig/drive the ground rod through a gas line, water line, electric service feed, phone lines, sewer line, cable/communications line, etc.--It can work.

    In my area, a 330 watt GT power system will generate around $0.25 worth per day of electricity in nice weather (or offset that amount of power--Depending on how the utility meter is configured). It is a lot of burden for the, relatively few folks, that would ever install such a system.

    If you want to put a ~4kW array on a ~3.7 kW GT inverter... That is going to need a dedicated 240 VAC @ 20 amp branch circuit anyway... They only plug and play outlet I have would be for an electric drier or stove--And those outlets are nowhere near the roof in my home. And if we need to "share" or figure out a "smart plug and play outlet"--It would require some changes to my home wiring anyway.

    The NEC (national electric code) is, at times, a pretty "simple"/brain dead in how they approach safety... On the other-hand, there are 100,000,000 residences out there and there are, roughly, 700,000 electricians out there. If you do not have a common approach/set of rules--Very quickly wiring in homes/apartments/etc. will fall into a mash of "standards". And each time you hire an electrician, he or she will have to figure out what you have and how to safely move forward.

    I have worked around a fair amount of electrical over my life--I am no electrician, but this electrical+safety stuff gets very deep, very quickly. The standards are a layered approach that take material, thermal dynamics, environment, safety, and human behavior into account when these codes are written. Even if you figure out a "short cut" for one issue, there are 2-4+ more issues that also need to be reviewed before something can be deemed safe and reliable.

    Are there lots of "Guerrilla GT Solar" installations out there? You bet there are. Will most of them work OK and not burn a house down or kill a family--Yep. Will there be some that do? Yep. Are there fires started by licensed electrical installations that follow the code (or not) too? Yep.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    and if you reread what i said that with the proper gauge wiring it will be fine except that it can be plugged into other outlets that can make it unsafe and pnp makes it too easy for that to happen.

    i am right in my example that you can get 15a plus 3a solar available on the wire for anything that could be plugged into that circuit. it is illegal to place 18a on a wire rated 15a. i suppose you would take anything that goes against what you wish to be as a bit rude, but read my type as it is unsafe and it is illegal for the reasons i stated. it would be safe if the wiring current ratings aren't capable of being exceeded and it is hard wired.

    of course solar needs approvals and inspections too, but i'm going purely on what they approve of and why. if that's rude, oh well.
  • BB.BB. Posts: 27,698Super Moderators admin
    igor1960 wrote: »
    Wrong! 15A downstream and 3A upstream exactly in sync. (and P&P inverter does it) is exactly 12A downstream

    Cannot guarantee that--...

    Breaker 14 awg wiring to outlet A and 14 awg wiring to outlet B.

    Plug 3 amp GT inverter to outlet A, and plug electric heater and hair drier into outlet B. Draw 15+3 amps in cable from A-B. That exceeds the NEC rating for that run of wire (there is a whole other issue with 14/12/10 AWG wire which, for some reason is "derated" by the NEC--that I could never fine. The tables will tell you that 14 AWG wire is god for 20 amps--However, a footnote tells you that 14 AWG is only allowed behind a 15 amp breaker).
    However, even if you are right: as I said 15a CB would be tripped at 15A => however I've mentioned that our circuit has 30AMP gauge wires, outletrs and etc., so 18A would not damage it...

    But now I would need to design the cords I plug into the "15 amp available" from utitilty + 15 amp from GT inverter to deal with 30 amp available current (middle of a sunny day). Now the 14-16 AWG extension cords and plugs would either need a Fused plug (like they do in the UK) to limit maximum current to 15 amps, or we would need to put 10 AWG cable on all of our hair driers, TV's, laptop computer power supplies, etc. Makes cabling for our appliances more expensive, heavier/bulkier, and/or adds another point to debug (fuse in plug).

    Could it be done--Yes. But read back through the "Ring Circuit" link I provided. You are essentially reproducing the Ring Topology that has been a "Standard" in some homes for the last 70 years. And even the UK/Ireland/etc... It is still not very popular because it takes 5-6 times longer to verify installation/safety of such a system (verses a standard point to point/"Star" wiring from a single power source).
    And then to everybody: Are we talking about "unsafe" receptacle? If yes, then OK, I agree: better to come up with $2 new electrical outlet/receptacle/plug design/implementation/standard, then to kill idea of Plug and Play, just because current receptacle allows to connect it anywhere. But isn't this a small issue?!

    100,000,000 homes with say 10 outlets/plugin appliances per home--Roughly a 1,000,000,000 outlets, cord ends, extension cords, etc. to change to the "new style" plug and play standard. It is a pretty big deal.

    Short of placing a fuse/breaker in every plug, or on every electrical outlet--I do not see a technical fix that will meet your desires and the requirements of the NEC.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • igor1960igor1960 Posts: 85Solar Expert ✭✭✭✭
    BB. wrote: »
    Draw 15+3 amps in cable from A-B

    Again you are making wrong assumption: 15amps downstream and 3amps upstream perfectly phased will give you 12amps in cable from A-B (15-3). Only 180 degrees rotated, they will give you 18amp in A-B (15+3), but that's not how inverters work. OK, they might introduce reactive energy and there power factor might not be that perfect, but still it's in 0.8-0.95 range. Meaning then in your example proper number would be in A-B: 15amp - 3amp*PF= 15-3*0.8=15-2.4=12.6AMP downstream...
    BB. wrote: »
    am not sure what else to say... If you have an outlet designated to connect to a 15 amp circuit... The wiring, breaker, outlet, and even the appliance cord (or extension cord) are designed for 15 amps * 0.80 NEC derating = 12 amp continuous power.

    Again, you are missing the point: our circuit wires, outlets and etc. are all designed for 30AMP current: only circuit break iinstalled is for 15AMP.
    Meaning, we can have plug&play inverters production equal to or less then 15AMP. At the same time, we can perfectly have 30AMP load on other outlets on the same circuit, which is OK, as our wires, outlets and etc. are all designed for 30AMPS. Circuit breaker will not trip, as current through it is less then 15AMP (30Amp loda - 15 amp inverters)production).
    Now, when the sun goes down, our inverters production drops to 0 and 30amp load would start to be served through 15AMP circuit breaker -- which will trip. ANd that's it...

    At no time through the whole cycle we had current more then 30AMP in our circuit -- so, what could go wrong?
  • BB.BB. Posts: 27,698Super Moderators admin
    Nope--You are wrong... AC or DC does not matter here. The basic of 15 amps from Breaker + 3 amps from outlet A = 18 amps available at outlet B to an arbitrary load.

    Breaker and wiring only "care" about current (specifically RMS current). PF, phasing, etc. does not matter in the above example. Problem would be exactly the same if this was a set of DC power sources and a DC load.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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