Positive grounding of a PV solar system?

Question

HAVE BEEN ADVISED THAT DC SYSTEMS SOULD BE POSITIVELY GROUNDED, AS OPPOSED TO NEGATIVE. THE THREE ITEMS THAT NEED TO BE POSITIVELY GROUNDED ARE PANEL, BATTERY AND LOAD. AM I CORRECT IN THINKING THAT THE POSITIVE TERMINALS OF THESE THREE ITEMS SHOULD BE CONNECTED TO THE SAME GROUND STAKE?

THANKING YOU IN ANTICIPATION

Answer 1

There are two distinct advantages to grounding the positive leg of a photovoltaic solar system. They both relate to leakage to ground. This occurs primarily because of moisture.

Electrolytic corrosion occurs at points of leakage. If the negative leg is grounded, the corrosion eats the material on the solar system side. Usually wires. If the positive leg is grounded, the corrosion occurs on the material of the accidental ground

The second advantage is that the corrosion barrier becomes a diode. When the ;positive leg is intentionally grounded, the diode is such that it minimizes leakage current.

This is why telecommunication companies utilizing metallic conductors always ground the positive leg on their systems.

Answer 2

Who ever told you to use positive grounding is dead wrong. In these modern times, the negative terminal is grounded. Since the 1960's, even cars have used negative grounding. Either that person is thinking of current flow, which one theory is that current flow is from the negative side of the power supply, they might have been seeing if you would fall for a dumb joke, or are terrible confused. In any case, ground the Negative side, NOT the positive. Your panel, batteries and load should all be grounded together at the same place. Get a copy, or search the magazine on the web, of Home Power. If you believe no one else, believe the people who make a living installing PV systems. They'll tell you, ground the negative side of the system.

Answer 3

I don't know why this should be a requirement as motor vehicles are quite happy with negative chassis. But if you are using positive earth then you are correct, these should all be connected to the same ground stake. You should check that your PV panel's frame is not connected to the negative or any mounting bolts could make a short circuit. Does it in fact need a ground stake at all? Is this just for lightning protection?

If you use automotive equipment as a load then be aware that the chassis of an inverter or radio will be negative. If this touches ground, say with an audio cable or by touching a water pipe you will get a short circuit.

Answer 4

PV system grounding encompasses issues ranging from equipment grounding strategies, including bonding modules and grounding racking support structures, to system grounding considerations, including grounding electrode system options. Grounding PV systems correctly and effectively is difficult—and the topic is frequently contentious—because there is no one prescription for either the design process or the methods and materials.

http://www.solarenergy.org/

Answer 5

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