Author Topic: Suggestion for EEVblog topic: Dangers of using Mains Earth direct  (Read 4320 times)

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Offline DanBTopic starter

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G'day Dave,

As I mentioned in a recent forum post (re: EEVblog #51), if you haven't already done so, may I please suggest a topic on the dangers of using Mains Earth direct, especially for use in personal ESD shielding and maybe even radio projects.

Like myself, until I was educated in the 'proper ways', I'm sure there are many viewers who have thought this practice to be OK and hey, why not! Earth is earth, right? Ouch!

Still getting through viewing all your blogs - only up to 51 :)
 

Offline vk6zgo

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Re: Suggestion for EEVblog topic: Dangers of using Mains Earth direct
« Reply #1 on: June 05, 2015, 08:29:24 am »
You've got me lost on this one!

Earth mats for ESD protection,as well as wrist straps are commonly connected to Mains Earth via a large value resistor (1MegOhm or more).
Even if the Earth connection was somehow elevated to Mains Active voltages,insufficient current would flow to harm you.

What I don't like much is the connection of such an Earth lead via a normal mains plug where the lead could contact one of the other pins.
Proper plugs are available--though,again you will be protected by the series resistor.

Never leave this resistor out!
Radios have been earthed to the Mains Earth for many decades with a vanishingly small risk.

What are the "proper ways"?---It seems like you are the only one in the parade marching in step! ;D
« Last Edit: June 05, 2015, 08:32:38 am by vk6zgo »
 

Offline Deathwish

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Re: Suggestion for EEVblog topic: Dangers of using Mains Earth direct
« Reply #2 on: June 05, 2015, 08:34:45 am »
Question: why does everyone wear a wrist strap, why not an ankle one, I hate having anything round my wrists, its a pain having to wrangle it around with its lead.
Electrons are typically male, always looking for any hole to get into.
trying to strangle someone who talks out of their rectal cavity will fail, they can still breath.
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Offline tautech

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Re: Suggestion for EEVblog topic: Dangers of using Mains Earth direct
« Reply #3 on: June 05, 2015, 08:40:55 am »
Question: why does everyone wear a wrist strap, why not an ankle one, I hate having anything round my wrists, its a pain having to wrangle it around with its lead.
The Aussies historically all wore them..... a ball and chain.  :-DD
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Offline lincoln

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Re: Suggestion for EEVblog topic: Dangers of using Mains Earth direct
« Reply #4 on: June 05, 2015, 09:54:58 am »

Question: why does everyone wear a wrist strap, why not an ankle one, I hate having anything round my wrists, its a pain having to wrangle it around with its lead.
<<edit >> sorry I was not done with that

I have only seen them in use in a fab environment (semiconductor / clean room) and the generally suck. (not that they are used else where, that is the only place where I have seen them exclusively used.)
You need to have a clean and dissipative floor for them to have any chance to work. That being said you can put on a fresh booty and about half the time they will not past the tester. In the fabs they use them because you are covered head to toe in what ever they make the suites out of. there is next to no bare skin to get a wrist strap on.

I suppose a stock room would also be a good application as well


« Last Edit: June 05, 2015, 10:05:38 am by lincoln »
 


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