When did they start requiring ground screws on yokes?

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Barbqranch

Senior Member
Location
Arcata, CA
Occupation
Plant maintenance electrician Semi-retired
Just curious, does anybody recall approx. when they started requiring the ground screws on switch yokes? Please don't spend any time looking it up, but if you remember that would be nice.

The reason I am asking is here in the plant break room, there were some lights that haven't worked in the 2 1/2 years I have been here. Finally took time to fix, and someone apparently had to replace a 3 way switch. Well, the on-off switch they had had 3 screws, so that must work. Lights didn't work, but apparently nobody could figure out why. Fortunately nobody got hurt from the switch plate screws that were hot.

These are the trouble shooting calls I like to figure out, but it also makes my ears smoke thinking how stupid and dangerous it is.
 

don_resqcapt19

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Staff member
Location
Illinois
Occupation
retired electrician
The mounting screws are permitted as the required grounding method for the switch yoke by 404.9(B), but that only works when the switch is installed in grounded metal box. The grounding screw on the yoke is needed where the switch is installed in a non-metallic box.

While there have been general requirements in Article 250 that would have likely required the switch yoke to be grounded, the first specific rule for that was in 380-9(b) in the 1999 code. That became 404.9(B) in the 2002 code. I would expect that after the 1999 code you started seeing grounding screws on the switch yokes.
 

Jon456

Senior Member
Location
Colorado
There's really no way to cure the problem you described. Removing the ground screws from yokes is certainly not the answer.

As they say, "Make something idiot-proof and they will simply build a better idiot."
 

480sparky

Senior Member
Location
Iowegia
Don is correct. The first specific requirement to ground the actual switch is the 1999. Prior to that, only the metal boxes that contained the switch(es), and any metal cover, were required to be grounded.
 

electricman2

Senior Member
Location
North Carolina
Occupation
Retired Electrical Contractor
A few years ago I went to solve a problem with lights in a home. The owner had replaced one of the 3 way switches. He used a 3 way switch and connected the travelers to two of the terminals and the hot wire to the ground screw.:eek:hmy: Told me the switch had an extra terminal and didn't know what was supposed to connect to it.
 

black_thorn

Member
Location
Pa
A few years ago I went to solve a problem with lights in a home. The owner had replaced one of the 3 way switches. He used a 3 way switch and connected the travelers to two of the terminals and the hot wire to the ground screw.:eek:hmy: Told me the switch had an extra terminal and didn't know what was supposed to connect to it.

Lol. You gotta love people that do electrical work that don't know what they're doing.

I recently was installing some ceiling occupancy sensors and power pack/relays in a commercial building bathroom. The lighting was 277, so I was splicing into the j box and found a circuit that ran to the hand dryers out of that box same j box. Out of curiosity I checked the plate on the dryers to see what the voltage was and they are 120v. The maintenance guy that installed them thought 1 hot was 120v and 2 hots made 277v. Lol
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
Lol. You gotta love people that do electrical work that don't know what they're doing.

I recently was installing some ceiling occupancy sensors and power pack/relays in a commercial building bathroom. The lighting was 277, so I was splicing into the j box and found a circuit that ran to the hand dryers out of that box same j box. Out of curiosity I checked the plate on the dryers to see what the voltage was and they are 120v. The maintenance guy that installed them thought 1 hot was 120v and 2 hots made 277v. Lol

Production went up because the workers hands got dry faster!;)
 
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