Lightning protection

gpigeon
gpigeon Registered Users Posts: 34 ✭✭✭
I am installing a Conergy pump and Linear Current Booster with the PV panel about 350 feet away from the LCB/pump. The installation diagram clearly shows an earthing (grounding) conductor running between the panel and the LCB/pump for lightning protection.
The supplier of the equipment has told me that they NEVER install ANY type of protection as they feel it is unnecessary.
Have any of you folk got thoughts/experiences/comments with regards to lightning protection?
regards.
Bill

Comments

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Lightning protection

    The high point of the system, needs lightning protection. Solar panel mounts likely.
    If you get a direct hit, panels, charge controller & inverters will be toast. Protection will keep it from creaming the rest of the system. A near strike, effects vary with the induced voltages.

    Your mileage may vary !
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.
    BB. Super Moderators, Administrators Posts: 33,433 admin
    Re: Lightning protection

    If you live in an area where you get lightening strikes--yes, you will want to protect your equipment.

    Do you have a HAM radio operator ([SIZE=-1]Amateur [/SIZE]radio operator) nearby? He (or she) would probably be a great source of lightening protection information for your area.

    Generally, grounding the heck out of everything to lots of buried copper and copper rods driven into the ground is a good place to start.

    Keeping the +/- wires together and twisted (if possible) several times per foot (or installing them in grounded metal conduit) too. Do not let the +/- wires take different paths (for example one turns left, the other right, around a post for the solar panel system). You run the risk of turning the differing runs/lengths of power cabling into a transformer coupling and inducing voltage/currents from the lightening into your solar power system.

    If you ground the negative lead of the solar panel system (not always sure that this is a good idea), ground it in only one place. If you ground it in, for example, two places (one near the panels and one near the well), you will pickup the difference in potential across the ground (the earth near the lightening strike will be at a high voltage, compared with that 100' feet away).

    Niel is a HAM, and others here live in lightening areas (I--luckily, do not), and can suggest the gauge of wire (I believe usually 6 awg (US) or larger is recommended) and other specifics.

    From my general electrical experience, I like Lightening Rods (grounded, pointed metal rods at high points on building/structures) to attract the strikes and lead the energy away from your electrical systems...

    But, I will differ to those with real experience over my "book 'learnin".

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: Lightning protection

    Consider the requirement to "ground" submersible water pumps. One's first thought might be - - why the heck should I run a ground wire 200 feet down into a well to ground the pump? No one will ever be down there to touch it and get a shock.
    Well, it has to do with protecting the motor from lightening. Without the shell of the pump "grounded" to your electrical system, the lightening tends to travel down the power cables, into the motor, where it blasts out through the windings to ground. Goodbye pump. If the shell of the pump is grounded to your electrical panel however, the easiest path for the lightening would be down the ground wire to the pump shell, from where it dissipates harmlessly (hopefully) into the water that surrounds it.
    Interesting stuff, lightening.
    Wayne
  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    Re: Lightning protection
    gpigeon wrote: »
    The installation diagram clearly shows an earthing (grounding) conductor running between the panel and the LCB/pump for lightning protection.

    The supplier of the equipment has told me that they NEVER install ANY type of protection as they feel it is unnecessary.

    regards.
    Bill

    That kind of thing happens when you buy from companies that don't know what they are doing.
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    Re: Lightning protection

    Ya know those round Delta lightning arresters that look like some wires just inserted
    into a bucket of sand ?? They start to conduct at somewhere around 8000 to 10,000 Volts.
    If you're going to use those, put them at the tower, or the lightning end of the cable, not
    the equipment rack. I think they're supposed to catch the strikes and high voltages
    on the far end of the line, but to do it fast enough where there is a much lower
    amount of energy available at the equipment rack end and there, a lower voltage
    surge protector can take it the rest of the way.

    Some (a lot?) of the big wind turbine tower tops have a lightning rod and a wire from that
    rod running "around" the actual generator to ground.

    3 cents worth of something. maybe. hopefully, possibly.

    boB
  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    Re: Lightning protection

    The Delta thingies are not the best thing around, they just happen to be about the only thing at a reasonable price that might at least give some protection.

    Polyphaser are about the best, but with prices at around $90 to $150, it can be a hard sell. And they also have a limited voltage range - a 48 volt panel array is just about the max you can go to, so not much help for grid-tie systems.
  • gpigeon
    gpigeon Registered Users Posts: 34 ✭✭✭
    Re: Lightning protection

    Gentlemen,
    Thank you for your input to date. This is an issue over which there seems to be much controversy. As with most issues there are extreme views so I am planning to sit on the fence in the middle.
    I think that I will run an earth wire from the PV panel onto the PV panel support frame and then down into the ground onto 2 earth stakes spaced at 10 feet apart. The ground is always moist at a depth of 3 feet. Because the PV panel and the pump/controller are so far apart (350 ft) I will repeat the earthing system at the pump end of the system.
    The two conductors running from the PV panel to the controller I will twist together (they are double insulated XLPE 16 sq.mm - 5 AWG) and will be buried at a depth of 10 inches.
    I invite comments/critisisms on the above plan.
    "Windsun" - you may recall my earlier thread. "Shurflo vs Conergy"! I wanted to deal with a "reputable" supplier such as NAWS but they would not answer my emails and still have not done so (apart from personal messages from you). Admittedly I ended up paying a little more for the Conergy pumps and LCB's from the local "Aussie" supplier but at least they communicate with me and I have the goods in the hand.
    Regards.
    Bill W
  • Mangas
    Mangas Solar Expert Posts: 547 ✭✭✭✭
    Re: Lightning protection

    In our desert mountains we get some firece electrical storms.

    Our electrician spent a lot of time installing grounding systems for the array, solar mechanicals, well pump stations and the house.

    He recommended I not install lightening rods, etc. The electrician's past commercial specialty was grounding large industrial projects.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Lightning protection
    Mangas wrote: »
    In our desert mountains we get some firece electrical storms.

    Our electrician spent a lot of time installing grounding systems for the array, solar mechanicals, well pump stations and the house.

    He recommended I not install lightening rods, etc. The electrician's past commercial specialty was grounding large industrial projects.

    installing grounding systems, but without the rods? what did he put in then, screens? as far as i know, be you on grid or off grid, you have to have an earth ground for your home unless you would have no electrical system.
  • Mangas
    Mangas Solar Expert Posts: 547 ✭✭✭✭
    Re: Lightning protection

    Hi Neil,

    They installed several ground rods but no above ground lightening rods on the house, mechanical room or pump houses..
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • 12vman
    12vman Solar Expert Posts: 25 ✭✭
    Re: Lightning protection

    Unconventional Grounding...?

    At the base of the tower that my panels are mounted on, I have 2-8' grounding rods in the ground spaced 3' apart. I connected the pos. lead to one and the neg. lead to the other from the panels. I've tested many times for current draw between the two during full sunlight with no issue. Low voltage doesn't seem to travel very far through the earth..

    This is the only source of grounding for my system. The tower is built with telephone poles. I've had some serious lightening strikes close to the house and everthing survived except my phone.. ;)
    ~Don
  • System2
    System2 Posts: 6,290 admin
    Re: Lightning protection

    I have an off-the-grid 12volt system here in Mexico and no grounds whatsoever. I guess I am a gambler at heart, but I don't have lightning protection nor insurance nor nothing. Let the good times roll amigos.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,433 admin
    Re: Lightning protection
    12vman wrote: »
    At the base of the tower that my panels are mounted on, I have 2-8' grounding rods in the ground spaced 3' apart. I connected the pos. lead to one and the neg. lead to the other from the panels. I've tested many times for current draw between the two during full sunlight with no issue. Low voltage doesn't seem to travel very far through the earth..

    Hmmm, interesting solution to the lightening problem... My concern would be is that you are going to quickly destroy one one of those grounding rods through electrolysis--and possibly some other nearby metal items in the ground too (like water pipes, well casings, gas mains, other grounding rods, etc...).

    Potentially, it would also make the system more susceptible to nearby lightening strikes (creates a voltage gradient in the ground, which is impressed onto your panel leads--the farther the rods are apart, the greater the possible voltage between them).

    Read about Cathodic Protection Systems...

    But, if it works for you--I am not going to argue.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: Lightning protection
    BB. wrote: »
    Hmmm, interesting solution to the lightening problem... My concern would be is that you are going to quickly destroy one one of those grounding rods through electrolysis--and possibly some other nearby metal items in the ground too (like water pipes, well casings, gas mains, other grounding rods, etc...).

    Potentially, it would also make the system more susceptible to nearby lightening strikes (creates a voltage gradient in the ground, which is impressed onto your panel leads--the farther the rods are apart, the greater the possible voltage between them).

    Read about Cathodic Protection Systems...

    But, if it works for you--I am not going to argue.

    -Bill
    =========================================

    My thoughts exactly.
    I remember a neighbor of mine, who's electric meter on his house never stopped, even with the main breaker shut off and he got me to check it.
    At the time it was only wired for 120 volts, not 240.
    After some checking, I put one lead of my FLUKE on his ground rod and reached out about 3 feet with my other hand and rammed the other meter probe in the earth. My suspicions were confirmed when the meter showed a 70 vac difference. The "hot" and neutral wires were reversed on his entrance mast, feeding hot 120 volts to his gnd rod. The farther out I moved the meter probe, the higher the voltage reading. He had been wondering why the snow always melted in a circle around his ground rod and no where else.:p
    And that's dealing with only 120 volts, not a lightening bolt nearby.
    All the best
    Wayne
  • 12vman
    12vman Solar Expert Posts: 25 ✭✭
    Re: Lightning protection

    BB..

    It has for years. I have trees near by that are taller than my tower and that's what seems to attract it the most. I have the metal mounting rack attached to the negative lead which keeps the static from building up on things..

    I dug down along side of the rods a few years back. I didn't notice any form of electrolysis happening anywhere. This was after 6 years in service..

    I tested and tested before I was happy with leaving it in line. I didn't see any form of conduction between the rods at any time. I even drained an above ground tank that I store rain water in around the rods and tested.. (375 gal.)

    Quote..
    "Potentially, it would also make the system more susceptible to nearby lightening strikes (creates a voltage gradient in the ground, which is impressed onto your panel leads--the farther the rods are apart, the greater the possible voltage between them)."

    This is the reason I kept the rods close togather. My first encounter with lightning was rather destructive. I had a ground rod at both ends of the house, Tied togather with 4gauge copper and everything grounded to the wire between them. Had a strike in a tree about 300' away and it cleaned me out! I lost everything that was connected to the battery, Including the controller. Polyphasers didn't help a bit. Since I've had this set up, I've had several close hits and the only thing it took was my phone. The phone line is over 2200' to the pole down by the road. The phone line grounding doesn't even stop that surge..

    I learned the idea from grounding communications towers. They practice single point grounding with a halo throughout the radio/equipment building. It seems to work for them so I decided to try it myself. So far, So good..
    ~Don
  • Patman3
    Patman3 Solar Expert Posts: 62 ✭✭✭✭
    Re: Lightning protection

    wow this subject sure generates posts! I helped a radio station tech build static discharge poles, which I think are way better than lightning rods. We sharpened points onto medium gauge ceiling hanger wire and inserted many of these into somekind of block, I can't remember exactly but it was similiar to this. I'm thinking of puting some of these (or similiar) up around the area to discharge lightning before it hits.

    http://porcupine.w4zt.com/