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View Full Version : Power Supply / Shock Hazard...?



whidbey88
12-11-2007, 05:54 PM
I'm building my first hot wire foam cutter. This first one is a bow/table design, not-CNC (yet). I have seen several designs for power supplies for the cutting wire on the internet. Everything from doorbell transformers to soldering guns. I've finally settled on using a 6/12 Volt car battery charger that has settings for 2/10/50 amps. I am using 80lb stainless steel "Hard Wire" fishing leader as my wire. This wire seems to hold up better than NiChrome in the tests that I've run so far.

I've tested this set up with the following settings on the battery charger:

6 volts, 10 amp = Very good setting for foam. Does not get the stainless wire red hot. Does get the NiChrome wire red hot.

12 volts, 2 amps = Gets the stainless wire red hot. Worked well for slicing slowly through wax. I did not even try the NiChrome wire at this setting.

To be honest with you, I don't know a lot about DC current and what the shock hazards are at these voltages/amps. Obviously, I take great care when using this device, but electrical current scares the hell out of me. Could anyone out there enlighten me as to what the shock hazards are if I were to accidently contact the wire? I know I would get burned, its the electrical shock that I am more concerned about.


Thanks,
Ken - newbie

Al_The_Man
12-11-2007, 08:05 PM
According to the code, up to 24v is not considered a safety hazard, any voltage up to this level does not have the capability of providing lethal current.
The resistance offered by the human body requires a higher voltage in order for lethal current.
BTW in your test you need to record the actual Voltage and current, not the value indicated by settings, as the first one would be much higher wattage than the second.
i,e, 1/ 60w 2/ 24w.
The results contradict the wattage should the numbers be accurate.
Al.

whidbey88
12-13-2007, 11:39 AM
Thanks Al. Good stuff to know. ~K