Quote:
Originally Posted by cajunfj40
MightyMirage:
Thank you for your reply - caution is merited here.
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I'm primarily interested in whether there is a difference in the danger other than the ability to jump a larger gap and sustain an arc over said larger gap.
The referenced "Red Suzi" thread has some really good detail on minimizing the potential voltage between any two nearby parts, and thus reducing the chance of an arc flash incident. That builder was attempting to keep the DC voltage potential in any given battery box at 24 or 48 volts, to keep it in the "Safety Extra Low Voltage" range below 25VAC/60VDC (though not explicitly stated as such, that was the effect) where no contact protection is required (IEC 60449). Contact protection is required between 25-50VAC and 60-120VDC, per the same standard, but it is still classed as "Extra Low Voltage Class III". It appears that anything above 50VAC/120VDC goes to "Low Voltage Class II", and that rating and protection class are good up to 1500VDC/1000VAC (EN 50110). I'd make sure I'd meet or exceed any contact protection needs, insulation needs, etc.
Basically, the reason for the question is that the common 144VDC DIY battery pack size, and common OEM 300-400VDC battery pack size are already in the "Dangerous - special gear required" range - and the exact same standards apply for the full range of 120VDC to 1500VDC. I want to know what the actual additional hazards are when moving from 350-400VDC to 700-800VDC, given that said voltage is still within the same hazard class per international standards. I can read technical standards and documents, but I don't know about all of them - if you can point to reports showing a "danger curve" or similar WRT the voltage in a system, I'd very much appreciate it. All I can find are the aforementioned standards that are biased towards grid-connected wiring, and some Arc Flash Potential calculations that assume 25,000A available fault current. I won't have that much. Maybe 2500A, more likely 1500A or less, since I'll likely be using 50-80AH batteries.
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the classification between 120v and 900v May be the same on the internet but your only seeing half the picture. potential energy is what counts not a textbook classification. i can tell you, nobody takes a 500v+ panel lightly whatsoever. green shields, cotton clothes with outer blast garments, leather covered in rubber gloves are the basics.
the potential energy built up in a 1500amp system at 800vdc is a freight train of pain. i know you don't like hearing this but truly stay away from these voltages unless you are certified. I've been doing high voltage electrical work for ten years, and your asking, on the internet,how to safely wire, insulate, and operate something that can kill you from 5 feet away...
Google search the requirements for entering a 10 calorie panel and ask yourself if you really think it's worth it still, because after all, i do believe this is where you would fall.
if you have a specific question ide gladly try and answer it for you, though.
Quote:
Originally Posted by freebeard
I suggest fewer 'o's in your 'too's. 
] g. |
