diy solar

diy solar

Amazing length of time walking after a 2300V arc flash

This is why I refuse to mess with this stuff beyond 480 when live.

I don't even like 480. Hell, I've got 230v machines with 600v servos and stay far away from those circuits until verification that everything is dead.
 
I don’t mind working on stuff 560 and below, it all acts the same… no clue about anything beyond that, and do not plan to increase my experience.

As many times as I’ve been bit with 277, 240, 120, etc… I am EXTREMELY careful around 440+V…

Grandpa and I were rebuilding some 560V RTU equipment, and he reached in to “test” for voltage with his bare hand like he has done thousands of times before… 560 humped his wrist, and he bounced back about 10’ and looked up at me and said… that one has some BITE… that was 30 years ago, and I remember it like it was yesterday… I use a meter…
 
I'm working with over 300VDC on this new single string of panels this week (wow, 100% charged by 10am... OMG but I digress)... I make sure to go pee before I even go near the stuff, lord knows last time I laughed so hard I cried down my leg.. don't need that happening again.
 
It is so tragic when things like that happen. Working in some of those same conditions I can also offer this bit of advice if you are working on a high-voltage solar setup that might not arc, but will POP and scare the heck out of you if something goes wrong.

Watch for secondary jerk-reaction injury. I have approached and tested terminals, and changed arm positioning, because if something does go off with the sound of a shotgun shell, you are going to jerk involuntarily whether you are ready for it or not.

So, knowing that, if it appears that a possible jerk will ram my arm/elbow, or whatever into something even worse and cause injury, I'll change my angle of approach to allow for a safe involuntary reaction.

Ie, if you are on a roof near the edge checking out something high(ish) voltage and the big POP occurs for whatever reason, make sure your involuntary secondary reaction doesn't take you off the roof and change your positioning if you can.
 
Wow I guess its a good thing he died, some get it worse and survive. Warning: graphic you cannot unsee this- but you gotta see this.
If its too much to handle the comment below lightens things up. "He sure looks happy about it."
 
I had a scary arc even when testing 48v DC.
I was testing the current of a new 455w solar panel using my multimeter.
I did this before with 100w panels without issues.
My multimeter is rated for up to 10 amps.
The panel was connected to an isolator switch, which I tested on its terminals.

Just as I approached with my probe, I got an arc that burnt the tips of my probes, the terminals, and blew the fuse on the multimeter.

That was the last time I tested in-line current with a multimeter. Since then I got a clamp meter, much safer.
 
It is so tragic when things like that happen. Working in some of those same conditions I can also offer this bit of advice if you are working on a high-voltage solar setup that might not arc, but will POP and scare the heck out of you if something goes wrong.

Watch for secondary jerk-reaction injury. I have approached and tested terminals, and changed arm positioning, because if something does go off with the sound of a shotgun shell, you are going to jerk involuntarily whether you are ready for it or not.

So, knowing that, if it appears that a possible jerk will ram my arm/elbow, or whatever into something even worse and cause injury, I'll change my angle of approach to allow for a safe involuntary reaction.

Ie, if you are on a roof near the edge checking out something high(ish) voltage and the big POP occurs for whatever reason, make sure your involuntary secondary reaction doesn't take you off the roof and change your positioning if you can.
This is very true. The contractor that I hired to do the utility side of my Solar room took one look at my plans and said 4ft from the panel box and pv box to the back wall was too small. He stated he would not work on it unless it was built with at least 5.5ft of clearance. He said in case of a spark they needed sufficient clearance for knee jerk reactions to the spark or shock.
 
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Sad. I used with work with guys like these when I installed process control systems. I did see an operator get across a pair of 480V bus links. He didn't die (the discharge was through his forearm), but he was mess up.

They were getting inside a control cabinet to do "stuff" through a ventilation port (pulled the filter out). They did it this way to avoid having to turn off power by opening the cabinet door. Chemical plants were worse. Corrosive liquids mix very poorly with high power electrical equipment.
 
working on high voltage you learn to take off jewellery and keep one hand in your back pocket.
if you dont know how to do that you shouldnt be there. in the right conditions a 400v solar array can throw a few inches of plasma at you.
i used to repair big screen (commercial size) back projector tv sets and they were spicy enough. once a drip of sweat fell off my brow and hit the pcb like a 12 bore shotgun cartridge and thats with only a tiny current behind it
 
working on high voltage you learn to take off jewellery and keep one hand in your back pocket.
if you dont know how to do that you shouldnt be there. in the right conditions a 400v solar array can throw a few inches of plasma at you.
i used to repair big screen (commercial size) back projector tv sets and they were spicy enough. once a drip of sweat fell off my brow and hit the pcb like a 12 bore shotgun cartridge and thats with only a tiny current behind it
I used to have sonys most expensive kbr61 projection tv. One day I got home from work and turned it on, immediately heard a loud pop and smoke and flames were visible from the bottom of the cabinet. I took it apart later, and it seems a mouse had got into it and was perched on the high voltage power supply board right when I powered it up. 32kv had gone through his body and went to ground, and went into the back side of every IC chip in the chassis.
My $5000 tv was toast, and it was just 1 month out of the extended warranty I had purchased.
Funny sony had put wire screens on most but not all of the vent holes in the case. It was also shocking to see how cheaply the whole thing was made, a bunch of boards screwed to the insides of a giant particle board box.
It was cool in its day, multisize p in p you could move to each quadrant, and would display everything that was on 16 channels all at once. (In stills, each updating every three seconds)

I dont think tvs even do that today because they all go through cable boxes.
 
I've spent a lot of time working on airfield runway lighting systems, the threat is real. These are series wired, ungrounded systems with power supplied by constant current regulators . The voltage is 5000v for a closed loop and can reach 9000 if there an open circuit. The regulators are designed to increase the voltage to maintain the amperage. This is done so that a mile long runway with 70 lights plus taxiway signs doesn't have debilitating voltage drop. The regulators don't care if it's a load or a person , it just ramps up the voltage to maintain the amperage. In the 70s and 80s the 5k volt wires were sometimes direct buried in sand.
 
I've spent a lot of time working on airfield runway lighting systems, the threat is real. These are series wired, ungrounded systems with power supplied by constant current regulators . The voltage is 5000v for a closed loop and can reach 9000 if there an open circuit. The regulators are designed to increase the voltage to maintain the amperage. This is done so that a mile long runway with 70 lights plus taxiway signs doesn't have debilitating voltage drop. The regulators don't care if it's a load or a person , it just ramps up the voltage to maintain the amperage. In the 70s and 80s the 5k volt wires were sometimes direct buried in sand.
That sounds incredibly dangerous. Hi voltage kills people, I think thats why its called potential? Ive been hit by 6kv from a neon tube like used in a beer sign, fortunately I wasnt grounded and it was extremely low current as it was just a single tube. Nice tickle though.
Who hasnt touched a live 110v house wire? I have probably 10 times in my life, again just a tickle because wasnt standing barefoot in water or anything.
A workbench in a duplex I used to rent with really old 2 conductor receptacles always had some weird kind of stray voltage going through it that would shock me from time to time. Sitting in my chair I would touch the bench, holding a meter probe with one hand and touch the other probe to the asbestos tile over concrete floor, and regularly see 80 volts displayed on the meter. Never figured it out nor got hurt either.
 
I used to have sonys most expensive kbr61 projection tv. One day I got home from work and turned it on, immediately heard a loud pop and smoke and flames were visible from the bottom of the cabinet. I took it apart later, and it seems a mouse had got into it and was perched on the high voltage power supply board right when I powered it up. 32kv had gone through his body and went to ground, and went into the back side of every IC chip in the chassis.
My $5000 tv was toast, and it was just 1 month out of the extended warranty I had purchased.
Funny sony had put wire screens on most but not all of the vent holes in the case. It was also shocking to see how cheaply the whole thing was made, a bunch of boards screwed to the insides of a giant particle board box.
It was cool in its day, multisize p in p you could move to each quadrant, and would display everything that was on 16 channels all at once. (In stills, each updating every three seconds)

I dont think tvs even do that today because they all go through cable boxes.
It was actually Sony i worked for. kbr was not one of the worst built products. i can easily say sony was one of the best brands i worked on other than panasonic pro gear. i also used to service betacams. youngsters may laugh at the od projector sets but in the day they were a marvel.
ok you had over 100kv in the big ones and had crt life rated in triple digit hours but they were the best thing available and most people had never seen a tv bigger than 28"
mice are c#*nts though. im now rewiring my old soviet truck because mouse ate the tickle wire on the alternator and shorted out the whole system.
also my neighbours 2000E posh comuter controlled baking oven went tits up and on teardown it had a family of ex-mice nested in the glass fibre insulation and half the insulation chewed off the wires to the cables
 
It was actually Sony i worked for. kbr was not one of the worst built products. i can easily say sony was one of the best brands i worked on other than panasonic pro gear. i also used to service betacams. youngsters may laugh at the od projector sets but in the day they were a marvel.
ok you had over 100kv in the big ones and had crt life rated in triple digit hours but they were the best thing available and most people had never seen a tv bigger than 28"
mice are c#*nts though. im now rewiring my old soviet truck because mouse ate the tickle wire on the alternator and shorted out the whole system.
also my neighbours 2000E posh comuter controlled baking oven went tits up and on teardown it had a family of ex-mice nested in the glass fibre insulation and half the insulation chewed off the wires to the cables
Back in the late 80s to early 90s you would walk into any electronics store and in the TV section there were Sony Trinitrons with their gorgeous pictures... then there was everything else. I dont think I saw anything better until IIRC, "Proton" TVs came out? Before I had that KBR I had a Pioneer 40" projection, it was a big deal when it came out around 88 or so. God that was long ago that a 40" tv in a box the size of a small closet and needed to be serviced yearly was something to covet!
 
That sounds incredibly dangerous. Hi voltage kills people, I think thats why its called potential? Ive been hit by 6kv from a neon tube like used in a beer sign, fortunately I wasnt grounded and it was extremely low current as it was just a single tube. Nice tickle though.
Who hasnt touched a live 110v house wire? I have probably 10 times in my life, again just a tickle because wasnt standing barefoot in water or anything.
A workbench in a duplex I used to rent with really old 2 conductor receptacles always had some weird kind of stray voltage going through it that would shock me from time to time. Sitting in my chair I would touch the bench, holding a meter probe with one hand and touch the other probe to the asbestos tile over concrete floor, and regularly see 80 volts displayed on the meter. Never figured it out nor got hurt either.
This is why I rewire so many houses...
Cloth isn't a good insulator, it's amazing how much the power bill drops on houses I've rewired...
Lotsa lost watts...
 
This is why I rewire so many houses...
Cloth isn't a good insulator, it's amazing how much the power bill drops on houses I've rewired...
Lotsa lost watts...
cotton wrapped copper is also a temptation for the dreaded mouse too. its a pretty good insulator if wax impregnated but not as good as it is for starting fires
 
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