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Handling high voltage sources?

  1. Sep 1, 2013 #1
    Don't know which sub-forum this topic belongs to so I'm sticking it in here.

    I'm currently at a temp job testing hot melt machines that powers from a 240v 3 phase source. Electrical safety was never really emphasized in engineering school. Is there a standard list of safety protocols or 'do and don't do' when handling high voltage equipment?

    For instance, the machine is chassis grounded. Is it safe to poke around while the machine is live?
  2. jcsd
  3. Sep 1, 2013 #2


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    That would depend on what you mean by "poke around". That chassis to ground resistance is at a much lower resistance than your body. Just sayin'
  4. Sep 2, 2013 #3


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    IMO, there are two ways to gain experience in dealing with high voltages and AC Mains voltages. The first is to get an education as an electrician, since they deal with AC Mains voltages all the time. The second is to work with an experienced mentor in electronics design -- somebody who is very familiar with getting devices UL approved, including all of the electrical safety issues involved in that. It is just too dangerous, again IMO, to try to learn this stuff on the Internet. Even with lots of great mentoring and lots of experience, I still manage to shock myself sometimes, and occasionally accidentally set things on fire. Luckily no major injuries so far

    *And* if this is for work, you damn well better have a supervisor who is responsible for your safety and the safety of your coworkers. If you are trying to poke around on your own with AC Mains voltages at your work, either you or your manager should be fired. Instead, ask your manager or the safety lead for your group how you can learn to safely work on the machines, so you can safely do your job.
  5. Sep 2, 2013 #4


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    Do NOT "poke around" inside that machine with the power applied (on). You may be killed by a fatal electric shock!

    berkeman, in post #3 above, is correct! It is the responsibility of your employer to train you BEFORE you operate or maintain that equipment. Pay attention to the safety rules. REFUSE to "poke around" inside any equipment unless you are fully trained and prepared.

    WARNING! 240 Volts, 3 Phase power can KILL humans!

    This is serious. I find it surreal that you are even asking this here on an internet forum! Do not touch anything until you are qualified. Get help. Get training. Get certified. Survive long enough to collect your first paycheck. And finally, let us know how the safety training saved your life!

    Hoping to hear from you soon,
  6. Sep 2, 2013 #5
    If the machine has been set up properly it is a safe as any other industrial machine, which does not mean 100% and that a baby could operate it. Your term poking around is vague, and if you mean anything other than setting up the machine prior to use and operating the machine according to the manual, then 'poke' is a dangerous thing to do.

    Besides a risk of electrical shock from exposing live contacts by removing protective panels, there is also a risk of severe burns from these machines. I do not think you want to go sticking your fingers and hands into areas they should not be just to do a check to see if the parts that do the melt are up to temperature.

    Does your company require a simple walk around the machine, at the beginning of each operation just to see if the electrical cables look OK, and melt is not collecting in odd places, and any thing else that may seem out of ordinary.

    At the very least, you should have safety gear such as protective clothing from the hot melt and safety glasses, probably safety boots and your company might require a hard hat.

    If maintenance is ever required, disconnect the power at service panel and lock it and keep the key so no other guy but you can turn the power back on.
  7. Sep 2, 2013 #6


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    Good comments by all. Thread is closed.
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