Re: [DIYbio] Re: A simple and cheap >100V DIY electrophoresis power supply

On 07/04/2013 11:33 AM, Josiah Zayner wrote:
> Most all power supplies have the final DC output at > 100VDC and a couple hundred milliamps so that should not be an issue only
> with this device.

No, the safety problem is common to all that perform that way. It's a higher than safe power level.
So, it needs consideration in design, like insulated cabinet interlocks for both output wires.

On 07/04/2013 01:22 PM, Simon Quellen Field wrote:> Electric fences pulse the current, so that if you touch the fence, it hurts,
but you can then let go. This seems like a good
> safety measure to add to a home-brew power supply if we are using more than 15 ma.


And concepts like that...

"or until you no longer get a good run, or until the time it takes to do a run is out of the question. That will give us some data
to use in deciding whether the idea of a safe electrophoresis power supply is possible( it may not be). There are no safe shotguns
or chainsaws, but some people still keep them in their homes."

and decisions like keeping chainsaws around.

"The electrophoresis power supply in my lab runs at hundreds of milliamps so I feel comfortable using at least that much. "

Why? That sentence sounds like faith in brand names that will save one from electrocution. They won't.

And then again Alexey is right on target here:
On 07/04/2013 06:10 PM, Alexey Zaytsev wrote:> This whole discussion reminds me of the argument from the anti-GMO
> crowd. They take the theoretical worst case scenario and run it as
> something that's sure to happen.
> Just don't grab the damn wires. Isolating the output from the input is
> a good idea and allows you to grab individual wires while being
> grounded, but it's not a hard requirement. You should just know that
> the device you've built is not fool-proof, and handle it with care.

Josiah, you just don't sound very experienced with electricity and I want you to be careful.
Some of your descriptions are disconnected and inconsistent, thus, probably unsafe
experimenting going on. I like Alexey and Simon's style of suggestions best -- make it
less easy to make a mistake, but no need to go overboard.

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