Grounding if solar system




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  1. #1
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    Default Grounding if solar system

    Im not sure if this question was ever asked but could not find it on previous threads. I have a 2400 solar panel array on a corrugated roof ie 6 x 24 v250w in 3s2p and 6x 12v150w 6s . the two groups are in the same corrugated roof but in two different locations and each has its own mppt cc.I want to ground the system.my idea is to run a single yellow household earth wire from any part of the metal roof to an earth rod buried just outside the house. i also plan to connect the lead neg terminal of my 48v battery bank to the same earth rod and to also connect the earth of my 5kva invertor to the same earth rod.will this work in terms of lighning diversion and allowing the circuit breaker to trip when there is a shot circuit?

  2. #2
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    Default Re: Grounding if solar system

    OK.

    I am super reluctant to offer specific advise on systems like this. We are dealing with multiple earths/grounds that mustn稚/may use common points. We have the PV panels lightning earth, the battery systems DC ground and the inverters Electrical earth and even chassis earth.

    Unfortunately the words, earth, ground and chassis are often misused and incorrectly interchanged.

    First port of call is the Inverters manual. Look for installation instructions. The inverter may or may not have built in protection and isolation circuits.

    覧覧覧覧覧覧

    However, notwithstanding the above -

    DO earth the panels to a SEPERATE Earth spike in the ground. The PV panels frames will take a direct high current knock in the event of a direct strike and the protection system should feed the current AWAY from your system.

    DO NOT earth either the Neg or Pos lines of the PV panels - EVER. Leave them floating. Voltages here will be induced voltages from a strike. Ideally the PV panels neg and pos should be protected with proper inline fuses and surge protection bleeding down to the Electrical Earth. Also a High Voltage DC Isolator is a legal requirement.

    DO NOT earth either the Neg or the Pos lines of the batteries - EVER. Leave them floating. These lines should be protected with properly rates fuses.

    DO follow the Inverters manual for Earthing. The Electrical Earth terminal on the connector/terminal block should be the only earth connection on most systems. Chassis earth/grounding will be dealt with by the internal circuitry of the Inverters.

    覧覧覧覧

    The above offered in good faith, without prejudice, as a guideline only.
    Cheers

    ZS5KAD Yeasu Ft-897D
    2 V8's a V6 and an inline 4
    The nice thing about going the extra mile - the road is never congested.

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  4. #3
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    Default Re: Grounding if solar system

    Quote Originally Posted by Fluffy View Post
    OK.

    DO earth the panels to a SEPERATE Earth spike in the ground.
    As @Fluffy said, a separate earth rod (spike) installed correctly. This to be at least 3m away from the house earth rod and to the correct depth which can be anything from 5-12m deep to get the required low impedance earth reading. The best location is in soil that will most likely remain damp, such as where aircon condensation or your geyser pressure control will discharge.

    To answer your questions from a legally compliant perspective I suggest you go online to the SABS webstore buy and read SANS 1063 (earth rods, couplers and connections), SANS 10199 (design and installations of earth electrodes), SANS 10142-1:2017 (The wiring of premises. Part 1: Low-voltage installations).
    Last edited by mygoggie; 2018/05/05 at 09:14 AM.

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  6. #4
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    Default Re: Grounding if solar system

    Quote Originally Posted by Fluffy View Post
    OK.

    I am super reluctant to offer specific advise on systems like this. We are dealing with multiple earths/grounds that mustn稚/may use common points. We have the PV panels lightning earth, the battery systems DC ground and the inverters Electrical earth and even chassis earth.

    Unfortunately the words, earth, ground and chassis are often misused and incorrectly interchanged.

    First port of call is the Inverters manual. Look for installation instructions. The inverter may or may not have built in protection and isolation circuits.

    覧覧覧覧覧覧

    However, notwithstanding the above -

    DO earth the panels to a SEPERATE Earth spike in the ground. The PV panels frames will take a direct high current knock in the event of a direct strike and the protection system should feed the current AWAY from your system.

    DO NOT earth either the Neg or Pos lines of the PV panels - EVER. Leave them floating. Voltages here will be induced voltages from a strike. Ideally the PV panels neg and pos should be protected with proper inline fuses and surge protection bleeding down to the Electrical Earth. Also a High Voltage DC Isolator is a legal requirement.

    DO NOT earth either the Neg or the Pos lines of the batteries - EVER. Leave them floating. These lines should be protected with properly rates fuses.

    DO follow the Inverters manual for Earthing. The Electrical Earth terminal on the connector/terminal block should be the only earth connection on most systems. Chassis earth/grounding will be dealt with by the internal circuitry of the Inverters.

    覧覧覧覧

    The above offered in good faith, without prejudice, as a guideline only.
    Thank you so much. The amount of knowledge a person can get from this Forum's experienced members is so remarkable!

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