1. #1
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    Default Utility Control: Solar Panels?

    I saw this on another forum and felt a broader perspective is needed... does anyone have any information or experience with controlling electrical power from solar panels? Does it operate independently of a public utility or can they be connected, and in either case, where or what is the shut off point(s)?

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    I have no experience with these systems, but I found the following article, which seems like it has some useful information:

    http://altenergy.blog-city.com/gridi...ive_system.htm

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    i'm not sure if i understood all of that, but i think i got you could still disconnect the solar pannels at a connection at the utillity box?

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    Default You bet the building is still hot after the meter is pulled.....

    In any jurisdiction, a grid-intertied system requires inspection by the local AHJ and the utility. The department should contact the local Building Inspector and work out the details for appropriate signage and disconnecting means as part of the installation permit process.

    Another major issue is notification of the Fire departments by the code enforcement officials to make sure that facilities with redundant power (generator, wind, and and PV) are identified in the pre-plan book.

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    The house with solar panels may be on the grid, which means you still have to hit the main.

    The house with solar panels may also have one or more batteries in the house. You will have to figure out where these are, and disconnect them.

    There may or may not be a switch on the roof next to the panels themselves.

    You could turn off the main, and turn off the batteries, but the panels may still be generating electricity. There is also the issue of ventilating the roof. The panels are strong, and you probably won't be able to cut through them or move very quickly.

    Bonus: often times the panels are on the back of the house, where you may miss them. Newer panels look like roof tiles. You might miss the panels all together, turn off the main, start overhauling, and get a nasty shock.

    Hopefully others can add/amend this. I've been trying to find out more about this topic for a while now.

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    im under the impression that solar still has to run to the main dist box on the house. so if you are able to cut the drop then cut it and shut the box off to the house, if you pull meters, then that should kill the additional solar feed to the house.

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    Just how much electricity are these providing? I know depends how large and number of panels, but I mean the average setup. I'm wondering if it is just a trickle current? Not saying not to cut the feed but just how concerned should we be?

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    Quote Originally Posted by edge1317 View Post
    Just how much electricity are these providing? I know depends how large and number of panels, but I mean the average setup. I'm wondering if it is just a trickle current? Not saying not to cut the feed but just how concerned should we be?
    Many of the inverters are rated in the +10KW range. That's more then 50A of 120/240V power

    The other issue is the large quantity of storage batteries. If they short & runaway, there's a bunch of energy that needs to go somewhere. Not to mention the hazmat issue if their containment fails.

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    Quote Originally Posted by edge1317 View Post
    Just how much electricity are these providing? I know depends how large and number of panels, but I mean the average setup. I'm wondering if it is just a trickle current? Not saying not to cut the feed but just how concerned should we be?
    I recently read something that discussed this. I apologize for not remembering the source or the exact numbers, but the author stated that the current would be sufficient to cause someone to fall off the roof.

    Quote Originally Posted by LeatherHed4Life View Post
    im under the impression that solar still has to run to the main dist box on the house. so if you are able to cut the drop then cut it and shut the box off to the house, if you pull meters, then that should kill the additional solar feed to the house.
    From what I understand, the power goes from the panels to the batteries, then to the box. Like I said, I'm trying to find out more about this stuff. I would imagine that if you pull meters/shut off the box, there would still be current running to the box from the panels.

    I'm also curious how things work when the house is off the grid.

    Some cities have enacted codes that require panels to be a set distance from the ridge line, in order to leave room for vertical ventilation.

    I'm going to go out on a limb and say that we're going to be seeing more and more alternative energy sources. For instance, how would your department deal with this (remember that these things are over 100 ft tall): http://www.youtube.com/watch?v=4N4HQv-UyUo

    I'm guessing we'd just let it burn. But add a trapped worker to the equation, and it'd be pretty tricky.

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    Quote Originally Posted by LeatherHed4Life View Post
    im under the impression that solar still has to run to the main dist box on the house. so if you are able to cut the drop then cut it and shut the box off to the house, if you pull meters, then that should kill the additional solar feed to the house.


    the power from the panels shouldn't be affected by the meter, if it was you'd be getting charged for the power your panels generate. the only time it should go through the meter is excess that is getting sold back to the power company.

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    I'd be most concerned about rogue installations. Yes the code requires disconnects, etc., but that doesn't mean that every DIY'er trying to save a buck is going to do it by the book.
    ullrichk
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    So, in a typical rooftop installation, it has a disconnect from the panels to the batteries AND from the batteries to the house, or just between the panels and batteries to the house?

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    Most of the systems I've looked at have no backup power at all. The solar cells supplement usage off the grid, or they provide a surplus of power during the day to balance what has been used at night.

    I have seen systems with PV disconnects before the inverter and traditional disconnects from the grid. I have no idea if batteries would be tied in upstream or downstream of the PV disconnect.
    ullrichk
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    I can't speak about specific solar installations, but I did pick of some basic generalities about solar installations

    Solar Panels produce DC electricity. If light strikes them, they will make electricity. Unless there is some sort of connection on the panel themselves, the wires running from the panels to the power distribution system should always be considered hot.

    Different panels will produce different levels of voltage. The amount of light striking them affects the power output directly. The time of day, time of year, amount of clouds will produce different amounts of power.

    Even in the middle of the night, street lights and the lighting from your rigs will produce a measurable amount of power from a solar panel. Most likely not enough to hurt someone, but a measurable amout.

    If the system uses batteries, they will be wired into the system between the panels and the inverter. The inverter is what turns the power into usable AC current.

    I have seen some discussion amoung solar junkies about wiring the home for DC current so that they don't have the efficiency losses caused by the inverters. Using appliances and lighting from the RV world, this would be doable. With Solar Panels and backup batteries, the home might not have a meter at all. Fire in the battery room would be real nasty.

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