Jakes Posted August 8, 2015 Share Posted August 8, 2015 Guys Our system is completely off-grid. We are in the Karoo, it's (extremely) rocky. The 15 (250W) panels are a couple of meters away from the small dedicated building that houses the charge controller (100A M/C), inverter (5kW M/C), batteries (12 Narada REXC200's) and generator. The inverter supplies AC to our house, about 80m away. It also supplies another building (a shop/restaurant) that is also about 80m away, in a different direction. I'll appreciate your thoughts on the earthing of the whole system. I was planning to earth the frame of each panel with an earth clip, running to an earth spike in the ground next to the array. There's a 2-core plus earth cable running from the inverter to each of the 2 buildings. I was thinking of putting an earth spike where the power enters each building and connecting the building earth there. MicroCare wants the earth and neutral bridged at the inverter. I'll do that. I've also planned to put an earth spike at the servitude building and connecting the inverter earth there. I'll appreciate your comments on the following: Do you agree with the 4 earth spikes? Will you connect all the earths together? If I should do so, should I also connect the earth of the solar panel frames to the rest of the earth "network". The spike at the panels and the one at the servitude room will be about 8m apart. Would you rather see me use a single earth spike in stead of the 2? Earthing anything else on the DC side seems controversial, but I'd like to follow the correct (legal?) route. Anything else that I should do? Thanks a mill. J. Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted August 8, 2015 Share Posted August 8, 2015 HI Jakes It is complicated. Look at this thread http://powerforum.co.za/topic/168-solar-pv-panel-earthing/?hl=earthing and this video (1 hour long but good) Chris SOLARWIND and HyperCut 2 Quote Link to comment Share on other sites More sharing options...
HyperCut Posted August 25, 2015 Share Posted August 25, 2015 WOW that was just Awesome. Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted August 25, 2015 Share Posted August 25, 2015 The question now is, is your earthing ideas more or less complicated after watching that video? Quote Link to comment Share on other sites More sharing options...
HyperCut Posted August 26, 2015 Share Posted August 26, 2015 Nope, it just make sense how and why equipment grounding is a must! Chris Hobson 1 Quote Link to comment Share on other sites More sharing options...
Eugene Posted September 14, 2015 Share Posted September 14, 2015 The rocky Karoo is a problem, you need an earth spike tester to ensure that you achieve 10ohm or less, may even require a earth mat. Quote Link to comment Share on other sites More sharing options...
Jakes Posted September 14, 2015 Author Share Posted September 14, 2015 Hi Eugene. I spoke to the electrician who did the installation of the 2 buildings at our place. (He can also sign off my solar installation, although he didn't do any work on it). He preferred a spike at the solar panels, a spike at the battery/inverter building, and one each at the house and the shop. I used 1.2m spikes. Somehow I was reluctant to link the earth from the panel frames to the rest of the system, but I linked all the other earth wires He spoke about a tester of sorts to test the quality of the earths, but didn't look like he thought it was necessary. What would you have done? Thanks. Quote Link to comment Share on other sites More sharing options...
Eugene Posted September 15, 2015 Share Posted September 15, 2015 @Jakes The earth continuity must be 0.2 Ohm, test is done with a 500V meggar. As many earth spikes as possible to achieve 10 Ohms, test is done with a earth spike tester. These tests have to be done to complete the COC. PV panel frames must be connected to the common earth (equipotential bonding). Yingli installation pdf recommends that the negative also be connected to ground. Quote Link to comment Share on other sites More sharing options...
___ Posted September 15, 2015 Share Posted September 15, 2015 I would be very careful with grouding the negative on the panel. The current sensor of the mppt controller is often in the negative line, and if your inverter also grounds battery negative to the case (and you have the case tied to ground), or if negative is floating (which appears to be the case on my Victron), you could 1) end up with a parallel resistor across the current sensor of the mppt controller or 2) create interesting paths for currents to go... Quote Link to comment Share on other sites More sharing options...
Eugene Posted September 15, 2015 Share Posted September 15, 2015 Seems to be 2 systems, grounded and ungrounded, which refers to the dc component and not equipotential earthing. Guess it's best to confirm with the inverter manufacturers. Quote Link to comment Share on other sites More sharing options...
maxomill Posted August 7, 2017 Share Posted August 7, 2017 thanks Chris this at least answered my question Quote Link to comment Share on other sites More sharing options...
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