Where to Connect Anti-Static Mat to Leviton (no screw) Outlet?

Thread Starter

David_1138

Joined Feb 28, 2019
1
I'm ordering my first anti-static mat for soldering ICs in electronic musical instruments and noticed the grounding cord has a ring connector for attaching to the center screw of an electrical wall outlet. Trouble is, all the outlets here are Leviton outlets with no center screw. There are two screws at top and bottom, however. Should I connect to one of those? Other options? I've scoured the 'Net for two hours now and found nothing relevant.

Any advice is appreciated.

Thank you.
 

Yaakov

Joined Jan 27, 2019
1,601
I'm ordering my first anti-static mat for soldering ICs in electronic musical instruments and noticed the grounding cord has a ring connector for attaching to the center screw of an electrical wall outlet. Trouble is, all the outlets here are Leviton outlets with no center screw. There are two screws at top and bottom, however. Should I connect to one of those? Other options? I've scoured the 'Net for two hours now and found nothing relevant.

Any advice is appreciated.

Thank you.
Carefully check for continuity between the ground pin of the outlet and those screws. The path to ground doesn’t need to be low impedance, and anti ESD connections are through 1 Megohm resistors. Just remember that receptacles aren’t always wired properly, and though there is little danger in checking continuity, turning off the breaker wouldn’t hurt.
 

crutschow

Joined Mar 14, 2008
23,487
Although it's probably good to connect the static mat to earth ground it's not always necessary.
The important thing is to keep your body and the mat at the same potential, so if you connect your wrist strap to the pad before you handle any parts or place them on the mat, then there will be no static potential difference between you, the parts, and the mat.
The soldering iron tip ground should also be connected to the mat.
 

shortbus

Joined Sep 30, 2009
7,074
Don't count on the mounting screws.
Why? On every brand of outlet that I've ever installed the ground screw(for the wiring purpose) is in the metal frame of the outlet "chassis" and that is also where the cover plate screws are. This was originally done back when they still used metal boxes for the outlet, since it would also put that box at ground potential. The same is true for mains light switches, though not all of them have a ground wire provision.
 

Yaakov

Joined Jan 27, 2019
1,601
Why? On every brand of outlet that I've ever installed the ground screw(for the wiring purpose) is in the metal frame of the outlet "chassis" and that is also where the cover plate screws are.
I am happy to rely on the mounting screws but not on the installer. If properly installed, the metallic frame of the receptacle will be at ground potential. I always test outlets rather than assume they are properly wired.
 

MrChips

Joined Oct 2, 2009
19,379
You need to investigate the construction of your building.
Is it a residential, commercial, or industrial building?
Is it a detached single dwelling or a high rise apartment or complex?
Is the electrical service modern and up to date?
Do you have access to the AC service panel?
Is there copper cold water plumbing nearby?

Basically, you need to locate a true connection to earth ground.
 

gramps

Joined Dec 8, 2014
69
I am happy to rely on the mounting screws but not on the installer. If properly installed, the metallic frame of the receptacle will be at ground potential. I always test outlets rather than assume they are properly wired.
Not all receptacle and switches have a metallic frame. In fact some don't have a frame at all. The mount tabs are simply held on with rivets. Whether or not the tabs are electrically connected to the ground screw, I can't say.
 

mvas

Joined Jun 19, 2017
538
I'm ordering my first anti-static mat for soldering ICs in electronic musical instruments and noticed the grounding cord has a ring connector for attaching to the center screw of an electrical wall outlet. Trouble is, all the outlets here are Leviton outlets with no center screw. There are two screws at top and bottom, however. Should I connect to one of those? Other options? I've scoured the 'Net for two hours now and found nothing relevant.

Any advice is appreciated.

Thank you.
First, check the AC Voltages between Hot, Neutral & Ground in the outlet ...
H to N = ?
H to G = ?
N to G = ?
All voltages OK ?

Then kill & lock-out the Circuit Breaker at the appropriate Branch Breaker Box
Remove the cover plate

Look inside ..
Do you see a green or bare ground wire connected to the Ground Screw of the Leviton Outlet?
Do you have "continuity" ( low ohms ) between the Green Ground Screw and the Mounting Ear on the Leviton Outlet?
Do you have "continuity" ( low ohms ) between the Green Ground Screw and the Neutral Wire on the Leviton Outlet?

Finally, you need to verify that the "Back Side" of the Cover Plate Screw is bare - not painted.
If all checks OK, then yes you can use the Cover Plate Screw for your Anti-Static Ground Mat
Use an insulated ring connector - crimped to your ground wire - won't accidentally fall off.
Fasten using the Cover Plate Screw nearest a Ground Hole, not the Screw by the two slots.
Turn Power back on.
Done ...

Edit:
Using the above procedure, whether J-Box is Metal or Plastic, is irrelevant.
 
Last edited:

Yaakov

Joined Jan 27, 2019
1,601
Any advice is appreciated.
Thank you.
Here is some advice, not about ESD mats but about ESD wrist straps.

Never use one for the first time without first checking to make sure the resistance from the strap to the ground is 1 megohm. A wrist strap with a low impedance path to ground is an electrocution waiting to happen.

Periodically check your strap(s) and be sure they haven’t shorted (protect yourself) or opened (protect your components).
 

shortbus

Joined Sep 30, 2009
7,074
Not all receptacle and switches have a metallic frame.
But every Leviton Outlet that I've ever seen does, that is what the TS was asking about. And every one with a green ground screw that I've seen does. What brand of outlet has no steel chassis/frame?
 

djsfantasi

Joined Apr 11, 2010
5,683
But every Leviton Outlet that I've ever seen does, that is what the TS was asking about. And every one with a green ground screw that I've seen does. What brand of outlet has no steel chassis/frame?
Steel frame of what? The outlet or utility box? It’s been many years since I’ve seen a steel utility box. They are hard to find. Everything’s plastic (at least in residential construction).
 

gramps

Joined Dec 8, 2014
69
black-leviton-electrical-outlets-receptacles-r55-t5320-00e-66_1000.jpg
But every Leviton Outlet that I've ever seen does, that is what the TS was asking about. And every one with a green ground screw that I've seen does. What brand of outlet has no steel chassis/frame?
I can't speak to the Leviton brand. I was referring to the cheap ( ~ $1.00) receptacles seen frequently in the box stores, usually sold in bulk. Frankly I wouldn't use them in a dog house.
 

shortbus

Joined Sep 30, 2009
7,074
Steel frame of what? The outlet or utility box? It’s been many years since I’ve seen a steel utility box. They are hard to find. Everything’s plastic (at least in residential construction).
The outlet it's self. Even the cheapest ones sold around here have a steel frame, chassis or what ever you want to call it. It is makes up both the mounting bracket and the ground lug/screw connection and is riveted to the plastic outlet modules. Image from - https://www.electrical-forensics.com/Receptacles/ElectricalReceptacles.html

 

shortbus

Joined Sep 30, 2009
7,074
View attachment 171290
I can't speak to the Leviton brand. I was referring to the cheap ( ~ $1.00) receptacles seen frequently in the box stores, usually sold in bulk. Frankly I wouldn't use them in a dog house.
Next time you go to the box store either buy one or take your meter with you. I'm willing to bet that the hole where the cover screw goes has continuity with the ground screw. Never saw one that didn't, even the cheapest ones that don't have screws for anything other than the ground, the ones with push in slots for hot and neutral.
 
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