Help Stick Welder needed for experiment

[Korishan]

Yes in fact this is why I have been banging on about dc circuit safety and what a big yawn it gets here from the couch colonels.

Well, considering there is absolutely no information about the voltage of these panel strings, it's hard to say how many volts we're talking about here. I'm going to hazard a guess that these panels are "power grid" level and they are doing several *hundred* volts, not a poultry 48V (not saying that 48-60ish volts is safe, but no where near as dangerous as high voltage solar).

View: https://youtu.be/S9a2oPCIMr0

Here's an arc created with 1kV of power, and the arc is extinguished after a few inches of separation. He's only able to sustain the arc by slowly bringing his hands together when the arc is created. Otherwise the metal melts away and self extinguishes.

View: https://youtu.be/rlG2Y7hBZJM


Here's another and this is 400V. Weaker than the other, but it's still 10x higher than a battery voltage string possibly creating an arc.

And here's the math behind knowing what the gap is:

View: https://youtu.be/0XcZEiAR5bI


Which is V=D(distance in cm)*30,000
Now, with Solar Panel installations, I definitely recommend using very high voltage rated and proper breakers. Don't use AC breakers for Solar, or DC in general tbh unless it's rated for such.
For a Battery installation, the DIY crowd is running somewhat low voltage, which is <70VDC. Again, they should use proper DC breakers for such voltage. I recommend with this, and with the solar installation, to use 2 breakers in series for extra safety. Even if the breaker(s) are rated for the voltages that are being supplied.

I really don't get where you are saying that we have a "big yawn" about safety. This doesn't make sense. No where have we stated that using cheap or inadequately rated equipment would be ok to do. Quite the contrary.

The biggest reason why there isn't much content about solar installations is because most of us don't even have high voltage solar installations to begin with. And those who do, have had it installed professionally and they came with the proper hardware to make it safe for the owner; which means they didn't post comments/threads about the installation and get help with information/installation procedures because some else did the installation, not them.

 

[Boron]

Yes thats the spirit K. However some of these vids are deliberately abusive to safe operation, ie when you break a circuit, its done quickly, not deliberately creating a prolonged arc incident. Also the voltage was much higher than a domestic system ie 220Vdc vs 48Vdc. Notice the guy with the 4 panels (4 x 12V) bring solar cable together to create an arc. Supports my hypothesis that the arc quenches after a separation of ca 2".
I suspect that 1/2" would kill it on a 24V system (tbc).
I like knife switches - its the old school solution.
I have some samples of such devices in common use throughout the far east (original prewar Siemens design). I will be doing some test vids showing these in proper use (ca$10 ea 63A).
As you rightly point out, most members call the cable guy and he installs the entire system so not much DIY interest on this board. Off grid Solarists can get a system together for ca 25% cost of a commercial installer but you have to really know what you are doing - or you will burn your house down..