Solar panel wires shorted togather

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Discussion Overview

The discussion revolves around the implications of shorting the positive and negative wires of a solar panel system, specifically regarding wire heating and safety concerns. Participants explore the electrical characteristics of the wiring and potential scenarios involving grounding and lightning protection.

Discussion Character

  • Technical explanation, Debate/contested, Conceptual clarification

Main Points Raised

  • One participant inquires whether shorting the positive and negative wires of a solar panel would cause the wires to heat up.
  • Another participant asserts that wire temperature will increase if the wires are shorted.
  • A different participant suggests that a 12 gauge wire can carry 20A, and with two wires, it could handle 40A, indicating that while the wire will get warmer, it is unlikely to fail under the short circuit current of 6A.
  • One participant questions the reason for the inquiry about shorting the wires, suggesting there may be a specific condition anticipated.
  • A participant mentions that if a battery is connected at the far end and discharges into the short circuit, it could create problems.
  • Another participant expresses the intention to ground both positive and negative wires for lightning protection, noting the installation on a tall tower.
  • One participant comments on the difficulty of drawing power from a shorted solar panel and recommends grounding the negative side while using a Transient Voltage Suppressor (TVS) from the positive to ground for protection.

Areas of Agreement / Disagreement

Participants express varying views on the consequences of shorting the wires, with some agreeing that the wires will heat up while others raise concerns about safety and functionality. The discussion remains unresolved regarding the best approach to grounding and protecting the system.

Contextual Notes

There are assumptions about wire capacity and the behavior of the solar panel under short circuit conditions that are not fully explored. The discussion also highlights potential scenarios involving battery discharge and lightning protection that may not be universally applicable.

John1397
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I have a solar panel rated 20 volts and 6 amps power comes in on 4 12 gauge copper wires 2 for ground and 2 for positive and it is 50 feet long if positive and negative are shorted togather will the wire get warm?
 
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John1397 said:
I have a solar panel rated 20 volts and 6 amps power comes in on 4 12 gauge copper wires 2 for ground and 2 for positive and it is 50 feet long if positive and negative are shorted togather will the wire get warm?
Yes, wire temperature will increase.
 
I think a 12 gauge wire will carry 20A so two wires 40A. The short circuit current from your PV array isn't likely to be much greater than the rated 6A so yes the wire will get warmer but I don't think it would fail.
 
John1397 said:
if positive and negative are shorted togather will the wire get warm?
Is there a reason you are asking this? Do you anticipate some condition where the wires could get shorted?
 
If there's a battery at their far end, and that battery discharges backward into the short circuit, yes you might make some trouble.
 
I want to ground both positive and negative to ground this is mounted on a tall tower and when lighting strikes this will give a path to ground.
 
John1397 said:
I want to ground both positive and negative to ground this is mounted on a tall tower and when lighting strikes this will give a path to ground.
It's going to be kind of hard to draw power out of a shorted solar panel, no?

Instead, ground the - side and use a TVS from + to ground to protect the + side.
 
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