diy solar

diy solar

Earthing of panels

Fraser

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Mar 25, 2021
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Hi guys. Needing more help. I have 20 solar panels and they are on a metal roof connected to short metal rails. Can I not just earth the metal roof or one of the one foot metal rails that is screwed to the metal roof? or should I earth every panel? I have a 5ft grounding rod in the ground right near the roof. Any help much appreciated.

thank you
 
You should earth the structure and every panel, in the hole marker as earth. The rest of the panel doesn't have continuity, so it is to place the earth wire in the designated hole. If you drill, then it is not needed to be in that position.
The wires, should go directly to the earth box and to a separated earth rod in the ground. You should also use a SPD device to discharge any high voltage from the pv wires to earth.

quadro.jpg
 
It depends on the panel mounting system.

some systems are rated as continuous earth mounting, and they can be single earth wired.
Most homemade mounting solutions require individual panel earthing.
But either way, if mounted on metal, the metal also needs to me earthed.
 
You should earth the structure and every panel, in the hole marker as earth. The rest of the panel doesn't have continuity, so it is to place the earth wire in the designated hole. If you drill, then it is not needed to be in that position.
The wires, should go directly to the earth box and to a separated earth rod in the ground. You should also use a SPD device to discharge any high voltage from the pv wires to earth.

View attachment 52128
You should earth the structure and every panel, in the hole marker as earth. The rest of the panel doesn't have continuity, so it is to place the earth wire in the designated hole. If you drill, then it is not needed to be in that position.
The wires, should go directly to the earth box and to a separated earth rod in the ground. You should also use a SPD device to discharge any high voltage from the pv wires to earth.

View attachment 52128
I have isolation switches and inline fuses but no spd. Not sure how to size it for my arrays. We rarely have lightning so at the moment I’m going to rush out there if I’m home and disconnect stuff ?. My bigger array delivers just over 40 amps and nearly 190 v
Not sure if I can connect an spd to the rotary type isolator I have. If I buy an spd could I literally put my positive and negative wires in the top and then come back out like on your pic straight into an mppt? As you can tell I have no idea what I’m doing. ?‍♂️.
thank you for the help.
 
I have isolation switches and inline fuses but no spd. Not sure how to size it for my arrays. We rarely have lightning so at the moment I’m going to rush out there if I’m home and disconnect stuff ?. My bigger array delivers just over 40 amps and nearly 190 v
Not sure if I can connect an spd to the rotary type isolator I have. If I buy an spd could I literally put my positive and negative wires in the top and then come back out like on your pic straight into an mppt? As you can tell I have no idea what I’m doing. ?‍♂️.
thank you for the help.
Yes, you conect the positive to one side and the negative to the other. The earth is in yhe lower side. This is a parallel conection to the PV wires. When you have a surge in any of the array wires, like 10kA, the device will send that voltage and amps to earth. In that case, the visors will go red and you need to replace them. This will protect your charger from high voltages. The fuse protect from high current. If you search online you will find some shematics about to use of SPD in solar arrays.

I see many youtube channels and it is very strange most of DIY guys dont know this, and dont use it, to protect their sistems. This is a very cheap device and you will find it easy on aliexpress.

Just be sure about the working voltage, must be a DC voltage, the aproximate working voltage of your array, mine is 450volts so i choose a 500vdc, and about 10kA opening for the SPD
 
Yes, you conect the positive to one side and the negative to the other. The earth is in yhe lower side. This is a parallel conection to the PV wires. When you have a surge in any of the array wires, like 10kA, the device will send that voltage and amps to earth. In that case, the visors will go red and you need to replace them. This will protect your charger from high voltages. The fuse protect from high current. If you search online you will find some shematics about to use of SPD in solar arrays.

I see many youtube channels and it is very strange most of DIY guys dont know this, and dont use it, to protect their sistems. This is a very cheap device and you will find it easy on aliexpress.

Just be sure about the working voltage, must be a DC voltage, the aproximate working voltage of your array, mine is 450volts so i choose a 500vdc, and about 10kA opening for the SPD.
Yes, you conect the positive to one side and the negative to the other. The earth is in yhe lower side. This is a parallel conection to the PV wires. When you have a surge in any of the array wires, like 10kA, the device will send that voltage and amps to earth. In that case, the visors will go red and you need to replace them. This will protect your charger from high voltages. The fuse protect from high current. If you search online you will find some shematics about to use of SPD in solar arrays.

I see many youtube channels and it is very strange most of DIY guys dont know this, and dont use it, to protect their sistems. This is a very cheap device and you will find it easy on aliexpress.

Just be sure about the working voltage, must be a DC voltage, the aproximate working voltage of your array, mine is 450volts so i choose a 500vdc, and about 10kA opening for the SPD
Thanks. Yes I have watch many youtubers and they don’t say anything about it. My solar project has cost me £23,000 at this point and I don’t want it being destroyed. I have a couple of 63 amp dc isolators. One for each of my arrays could I sand which this 4 pole SPD between them and it will protect both arrays? I’m attempting to attach pics ?.
 

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The one you show me is for AC voltage, not DC. It must be DC for solar arrays.

You can use use one for each string, then send them for the same earth pole. Remember do not mix you house/inverter earth with structural/panels/SPD earth.

I boughy mine here -
So I could just get two 2 pole SPD? Thanks for the link. I can just use one of them with each one of my 63amp dc breakers and happy days. Do you think I should get another earth pole in the ground somewhere as well then. I have one for the house and one for all the mppt and batteries and inverter. Get another for the spd?
 
So I could just get two 2 pole SPD? Thanks for the link. I can just use one of them with each one of my 63amp dc breakers and happy days. Do you think I should get another earth pole in the ground somewhere as well then. I have one for the house and one for all the mppt and batteries and inverter. Get another for the spd?
Yes 2 SPD of 2 poles, one for each string.

About earthing, i would get one earth pole for the metal structure, panels suports and panels. That can be mixed with the earth from the SPD's, on a earth connection box. That earth pole spaced at leat 3m from the existing ones.
 
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