EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: nrgeek on February 02, 2012, 08:18:34 pm
-
Ok ... I know this is gonna turn into a pissing contest .. and will end up way off topic, before its all said and done.
But .. in my back bedroom aka my lab/workshop .. I have carpet on the floors, said something to the wife about getting a less shocking thing for the floor.. she starting bitchin lol.. more money blah blah blah lol
Anyway I was looking at the esd floor mats.. found some on ebay pretty cheap, figured I could but them down in front of my bench, that in combination of a esd mat on the bench .. all grounded of course.. my house was built in 2006 and have GFI outlets in the house.
Should I run a earth ground to the outlet or run out to earth ground to the meter earth ground.. or put in a separate earth ground and not use the meter earth ground to ground the ESD mats etc.
Will a esd monitor really do anything to help ? and how hard would it be to build one over buying one ?
Looking for some real answers not just a bunch of theory.. and pissing contests ::)
Thanks in advance
-
Should I run a earth ground to the outlet
No, you don't want to do that. For grounding purposes, you will always want to connect your ESD mat to earth ground. Typically, you can just security connect your grounding strip to a metal water pipe that comes into your house.
I haven't found the need for an ESD meeter ever. Depending on how sensitive the components you are working with, it may or may not be necessary. But for hobby work, an ESD mat is more than adequate.
-
The Grounding rod for the Electric meter , service head, is right out side the wall of my workshop, Im mainly doing repairs on laptops, lcd tv and monitors, and other electronics, and a few small projects built from scratch.
The pipes in my house are not metal, so that wont do any good lol.. is it safe to clamp on to the meter grounding rod, or should I use a separate grounding rod for the earth ground ?
-
Here's what I do .....
Mix 4 parts water with 1 part Downy fabric softener in a spray misting bottle then lightly mist the carpet in your shop (bedroom). This eliminates the triboelectric charging from the carpet, and should hugely reduce any ESD charges you can build. I wouldn't go for the expense of a floor mat. Just a well grounded wrist strap and bench mat.
BTW ... a good ESD meter is expensive. Mine cost about $1,600, and my ESD audit kit ran about $9,000.
John
-
Use both; safety ground (GFCI outlet for your equipment), and earth ground directly for the ESD mats (run a stranded wire between the ESD mats the ground rod at the service panel). This way, both grounds are connected eliminating a potential earth resistance issue.
If you're interested in further detail, take a look here: http://www.esdjournal.com/techpapr/eosesd/static/sgscw.htm (http://www.esdjournal.com/techpapr/eosesd/static/sgscw.htm).
-
Connect the ESD mats to the ground pin of the outlets on your workbench. That is all you need or want to do.
-
Make sure all ground connections for ESD purposes are high-impedance. The ESD mat will be high impedance, and there's usually another resistor in the cable connecting the ESD mat to the ground point. Both for ESD protection and safety. You want to prevent sudden electrostatic discharges, putting something with a possible charge on a surface with 0.01 ohm resistance to ground will produce a nice zap. You want to limit the current going through your body in the case of a shock. If you touch a grounded work surface with one hand, and happen to come into contact with a dangerous voltage with the other, then you can a nice jolt of electricity right through your heart. Same with grounded wrist straps. Adding resistance limits this to safe levels.
-
Make sure all ground connections for ESD purposes are high-impedance.
...
If you touch a grounded work surface with one hand, and happen to come into contact with a dangerous voltage with the other, then you can a nice jolt of electricity right through your heart. Same with grounded wrist straps. Adding resistance limits this to safe levels.
I second this idea, especially if you're working with power supplies on your bench!
Always double-check that your ESD mat is connected to ground via some high-impedance connection, especially since many ESD mats come with that wire that also doubles as the connection point for your wrist strap.
All it takes is a poorly grounded (a.k.a. hard-wired to ground w/no resistance) bench, an exposed power supply that's plugged in, and a split second of not watching where your hand is going to really ruin your whole day.