Midnite SPD's installation procedure

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unicornio
unicornio Solar Expert Posts: 217 ✭✭
in Off Grid Solar & Battery Systems #1
hi, there!

I finally go to install my SPD protections.

I had already thing to do in the two distribution boxes where I have space to put them comfortably. I want to protect 4 long cable runs that measuring over 200m and go to two buildings, as well as the two runs from the two arrays that are in the solar tracker, and I think the best place is right when they enter in the container, so close to the ground rod.

this is a 220 VAC plant, with two PV arrays with a 100 VDC VOC, and with floating neutral, not connected to earth. too, I have installed the outback GFDI at the input of the charge controllers...

attached an embarrassingly childish drawing Connection with Scheme...;-)
I wonder if any one of you guys think the situation are good and the wiring are correct? ...

many thanks to all!
regards!


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  • Organic Farmer
    Organic Farmer Solar Expert Posts: 128 ✭✭
    #2
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    Re: Midnite SPD's installation procedure

    The Midnite SPD wiring diagram is really simple. There is not much to it.
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #3
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    Re: Midnite SPD's installation procedure

    Organic Farmer, yeah! ... the connection is so easy, but I'm wondering, especially, for the place of installation. typically they are installed closer to the equipment, or in protection panels . and with the particularity that i have not connected the neutral to earth and the solar GFDI is in the arrays, before charge controllers ...
    i want to not missing something...

    thanks so much for your post!
    regards
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  • Organic Farmer
    Organic Farmer Solar Expert Posts: 128 ✭✭
    #4
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    Re: Midnite SPD's installation procedure

    One SPD installed near the panels. If they are hit with lightning, you want a device at that location to immediately shunt away the spike.

    One SPD installed at the Charge-Controller, so if a spike does get onto any of the wires [Negative or Positive] that spike can be shunted away to ground, before it can do any damage to any other component.

    The SPD itself connects to the Positive bus-bar, the Negative bus-bar, and to the Ground. Even though it 'appears' to be inter-connecting Positive, Negative and Ground, it is not. The only time current should flow through a SPD is during the millisecond of a Million-volt spike.

    It does not matter how you wired any other component in the system. You could have designed your system to have a grounded Positive, or a grounded Negative, or they could both be floating, it makes no difference. Because normal current does not flow through a SPD.

    Old-style SPDs made it a lot more obvious. Two electrodes mounted with a gap between them. Not touching, but a calibrated gap between them.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #5
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    Re: Midnite SPD's installation procedure
    Organic Farmer wrote: »
    The only time current should flow through a SPD is during the millisecond of a Million-volt spike.
    <snip>
    Because normal current does not flow through a SPD.

    That is not exactly true for Midnite's SPD. Those lights do consume a finite (but inconsequential) amount of the normal operating current.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Organic Farmer
    Organic Farmer Solar Expert Posts: 128 ✭✭
    #6
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    Re: Midnite SPD's installation procedure
    vtmaps wrote: »
    That is not exactly true for Midnite's SPD. Those lights do consume a finite (but inconsequential) amount of the normal operating current.

    --vtMaps

    Good point.

    I was looking at electric fence supplies last night. The lightning arresters used to protect an electric fence are very simply devices. A piece of ceramic with two posts an inch apart.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #7
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    Re: Midnite SPD's installation procedure

    unicornio.
    do as organic farmer recommends and the grounded lead of the spds shall go to the ground and not to the floated neutral. it may be more important to additionally have one at the array due to the fact you have electronics for the tracking as well as some spds to the input of the cc and utility side ac connection points. that makes 3 spds.
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #8
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    Re: Midnite SPD's installation procedure
    Organic Farmer wrote: »
    Good point.

    I was looking at electric fence supplies last night. The lightning arresters used to protect an electric fence are very simply devices. A piece of ceramic with two posts an inch apart.

    i have a electric fence, and i take note of this arresters!...may be i can to build one o this...
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #9
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    Re: Midnite SPD's installation procedure
    niel wrote: »
    unicornio.
    do as organic farmer recommends and the grounded lead of the spds shall go to the ground and not to the floated neutral. it may be more important to additionally have one at the array due to the fact you have electronics for the tracking as well as some spds to the input of the cc and utility side ac connection points. that makes 3 spds.

    as seen in the pathetic schemes that i draw, the spd's earth connection are connected very close to the ground rod, and i want to protect both, phase and (floated) neutral, and too, two couple of positive and negative that runs from two arrays of the solar seker...

    for that, i need to buy 4 spd's, that are very expensive!...

    looketh later as protect the other ends of the cables, two container buildings, the well water pump, and the solar seker power supply and control electronics,
    and too, thanks to Organic Farmer, also my electric fence that runs over 2 km ...

    vtmaps: so rigorous as ever!...;-)

    many thanks to all you guys!

    Health, Mates!
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #10
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    Re: Midnite SPD's installation procedure
    unicornio wrote: »
    for that, i need to buy 4 spd's, that are very expensive!...

    Midnite is working on some multi-phase SPD. If you use them (I don't think they're shipping yet) you would need less of them. They have a bit less clamping power than their existing SPD.

    a quote from this thread: http://midniteforum.com/index.php?topic=725
    Halfcrazy wrote:
    We are working on a 3 phase version. The downside is there will be less protection per phase as we can not fit any more MOV's in the case. I prefer on wind turbines to use 2 of the SPD's to get max protection.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #11
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    Re: Midnite SPD's installation procedure
    vtmaps wrote: »
    Midnite is working on some multi-phase SPD. If you use them (I don't think they're shipping yet) you would need less of them. They have a bit less clamping power than their existing SPD.
    --vtMaps

    i have the 4 MNSPD, they arrived today!...;-)

    i think i will need to buy 4 more MNSPD to protect the end of the cable that runs to the buildings and to the PV arrays, i will include this buy in the silly "happy new year" budget!....LOL
    but for now, and meanwhile, with this 4 MNSPD i will protect the entire power plant and the container that host it...;-)

    many thanks for your help!

    best regards, and
    Health, Mate!...
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #12
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    Re: Midnite SPD's installation procedure

    I have already installed the MNSPD300.
    and (I so lucky) today we had a good lightning storm. so I have endured it much calmer! ...:-)

    I have had very good impression of the quality and care with which they are built. It is the first product of midnite solar that I have in my hands, and really is amazing the ability of these guys do it right! ...

    however, I trust it before, because I know very well the extreme quality of outback products design, where these virtuosos also were involved. it is clear that everything they do, they do it well! ...

    unfortunately, the units sent to me must be old, because all are marked as serving for AC and DC.
    because of this, I suffer from the syndrome "only one of the LEDs light" in which are installed at the entrance of the cables coming from the PV arrays, probably due to the negative to ground bond ...

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    I warn they of this, at the place where I buy the 4 MNSPD, but it has not been for nothing, and I do not know if midnite can do something (to resolve) about this issue ...

    I understand that is true the fact that the LED that has no light does not mean any lack of protection, but it is also true that if the led light communicates something,(ie, the god state of work of the SPD's) is this case, that's a function that I will not be able to enjoy it.

    hope i can resolve it...

    regards
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #13
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    Re: Midnite SPD's installation procedure

    hi, there!

    i found this useful information about MNSPD300 led light issue, and i found here, in northern arizona wind&sun host:

    http://www.solar-electric.com/lib/wind-sun/spd_explanation.pdf

    really a very best internet site about solar energy systems, with the utmost rigor and technical accuracy!...;-)
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