Solar panels- to fuse or not

May 21, 2016, 11:20:28 am

Andy, I have to disagree about fusing, though it could be an issue if you have a large array parallel-connected before the roof entry. As an example, a 260W panel short-circuited would only produce about 17A, which is little different from its full-power output of 15A. So, how would you fuse that to protect the wiring? The best move is to keep the wiring down as protected as any other concealed wiring, as any shorts are just as likely to allow sparking WITHOUT blowing any fuse. Any fusing is a potential voltage drop across the fuse and any associated connection, which makes little sense in this case.

Steve

Re: Solar panels- to fuse or not

Reply #1 – May 30, 2016, 06:52:29 pm

I have not run across any solar panels with factory fusing nor do I fused solar panel wiring. Here's why.
Steve points out the difficulty of fusing a panel, due to small range between the full panel output and it's shorted output. Too small a different to properly fuse.
In my experience, any type of fuse causes voltage drop, another reason Steve pointed out why fusing is impractical.
So, how to protect from possible shorts to ground and burning the rig down?
Eliminate the possibility by double insulating all the wiring up to the solar controller. Enclosed all the wiring in soft, non-conductive plastic.
On the roof, instead of leaving the solar panels's cables out in the open, encase them in exterior electric conduct from the panels to the to a exterior plastic junction box. Once through the roof and into the interior, wrap the cables with split plastic tubing and securely clamp the wiring with plastic clamps and ties.
Never give the cabling a change to get near any grounded metal. Keep it protected and secured.
Exterior waterproof electrical boxes, conduct and fitting are all available at your local home center.
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Larry

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May 21, 2016, 11:20:28 am

Reply #1 – May 30, 2016, 06:52:29 pm

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