safety measures for heat blanket puncture?

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kungpowd
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safety measures for heat blanket puncture?

Post by kungpowd »

What are the safety options one could implement into the heating circuit of your press, incase a heat blanket is some how punctured or pinched and conducting electricity through your cassettes and or press frame?Tried searching but came up empty.Would gfi breakers work on heat blankets run with ramp up pid controllers?Would the gfi trip do to the fluctuating pid controller,or would it not matter because power supplied before the pdi is a constant steady amount of volts?Grounding out your press with a spike driven through concrete and into the ground overkill?Learning the basics and scrathing my head over the more technical stuff.I'm taking precautions as I remember building boards for a defunked company,and pulling cassettes out of the press with sweaty hands (latex gloves on) and feeling an electric buzz (not a jolt).We checked blankets for electrical leaks,they were fine.Covering all the angles so I can avoid burning money I dont have.Thanks in advance for any replies.This forum is a library of knowledge,thanks a million to all the folks who contribute.[/b]
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vinman
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Post by vinman »

I suppose you could ground your Alu sheets to your press frame and ground your press frame through the electrical panel or to a grounding post outside of your shop.

My press is ground through my sub panel and the sub panel is ground through the main panel. I used to clip wires from my Alu sheets to the press frame with a #10 wire and an alligator clip. Not sure why I stopped but I never had any issues either. Mostly because I don't handle the cassette when there is live current either.

I only turn the heat on after the laminate has been in the press for 10 min, then they get turned off to allow things to cool enough to handle before pulling them. So I guess there isn't a lot of chance to get zapped the way I do things.
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pmg
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Post by pmg »

The most common part for this is what they use in bath rooms, translation tells me its called earth leakage circuit breaker in english. (Is that the same as a gfi? couldn't find out what that means)

Used one of them when I build a belt grinder some years ago which can be run with water for cooling. Also has a controller "behind" the elcb for running it a any rpm I want, works without problem. And also switched everything off once ;)
gav wa
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Post by gav wa »

I'm just building my control box now and am fitting a 10amp circuit breaker with a built in 2 pole RCD into each blankets supply circuit. The earth is set up pretty much exactly the same as Vinman described. Remember a RCD (residual current device or also called an earth leakage breaker) only monitors shorts to earth, a short between active and neutral needs to be protected by a fuse or circuit breaker.
Run your earth circuit back into your building's earth circuit, it already has a proper earthing stake, you would be surprised how deep these sometimes need to go.
My press frame also has a simple connection to earth too.

It is pretty scary how people on here have said they sometimes get a tingle from their press when the heat is on.
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falls
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Post by falls »

cassette sheets (aluminium), press frame and control box (steel) are all linked back to building earth using the earth wire in the power cord for the controller.
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MadRussian
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Post by MadRussian »

falls wrote:cassette sheets (aluminium), press frame and control box (steel) are all linked back to building earth using the earth wire in the power cord for the controller.
+1 on this one.

My blankets in the press all the time and I don't see how they can be punctured. IMO DIY blankets shouldn't be moved around too much and especially rolled up. More one play around with it more possibility something go wrong.
If people get zapped from the blanket can be : 1 statute electricity; 2 blankets is not build correctly.
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