Is this device grounded?

[jaylectricity]

Has anybody plugged one of these into it yet? :grin:

 

[e57]

It's a dimmer....

 

[e57]

This IS grounded...

 

[JFletcher]

Hence my point earlier:

I missed that, as well as your post right before mine.

 

[jaylectricity]

It's a dimmer....

Swing and a miss.

 

[al hildenbrand]

Alright - It is exactly the same... Still not mounted to the box... And... Not grounded!

Wow. You're hot tonight. Nice graphic.

So complete the installation with the screws snugged down, and with the box set back as shown.

IMO, this is the heart of the question. A realistic, common, as-installed in the real world assembly. When the device screws are snugged down, is the heat sink / yoke bonded to the EGC?

 

[e57]

Wow. You're hot tonight. Nice graphic.

So complete the installation with the screws snugged down, and with the box set back as shown.

IMO, this is the heart of the question. A realistic, common, as-installed in the real world assembly. When the device screws are snugged down, is the heat sink / yoke bonded to the EGC?

Sure.....

Still not grounded!

Not secured to the box...

 

[electricmanscott]

OK, so what is the point?

 

[infinity]

I vote yes, once you install the plate and tighten it the mounting screws will be tight.

The screws only need to be tight, and a self-grounding device is not required. Actually I missed the part about the loose screws or I would have voted no.

 

[M. D.]

Sure.....

Still not grounded!

Not secured to the box...

The CMP diagrees with you :

____________________________________________________________
Submitter: Rod Belisle, NECA-IBEW Electrical Training Center
Comment on Proposal No: 9-95
Recommendation: “Accept” to read as follows:

Revise 404.9(B)(1) as follows:

The switch is mounted with metal screws to a surface-mounted metal box
with at least one of the insulating washers removed or to a nonmetallic box
with integral means for grounding devices.

Substantiation:
The requirements in 404.9(B) state that a switch shall be
“effectively grounded”.
The definition of effectively grounded in Article 100, states that it shall be
sufficiently low impedance and have sufficient current carrying capacity to
prevent the buildup of voltages that may result…
It is not accurate to state that a switch mounted on a non-conductive surface,
secured to a metal box that is recessed _”, therefore not touching the switch,
meets the requirements of “Effectively grounded”.
The CMP substantiated it’s vote by stating that the requirement is not the
same as the requirement for receptacles, but the terminology used in 404.9(B)
does not differentiate for the code user.
The use of the term “effectively grounded” needs to mean the same thing as
used throughout the NEC, as it is described in Article 100.

Panel Meeting Action: Reject

Panel Statement:
The proposed requirement is the same as 250.146(A) for
receptacles and as such is excessive for snap switches that do not form an
element in the extension of a circuit beyond the fixed wiring of a building
or structure. This has been the consistent position of CMP 9 on this point for
at least 70 years, and there has not been adequate technical substantiation
presented to justify this change.
Number Eligible to Vote: 11
Ballot Results: Affirmative: 11

 

[220/221]

Well.....The switch is mounted with metal screws to a metal box or metal cover that is connected to an equipment grounding conductor....so yes, it is grounded.

It doesn't say tightly or securely mounted, it says mounted to the box.

.


.

 

[e57]

The CMP diagrees with you :

Actually they disagreed with the writer of that particular revision... Not "ME" specifically... But thank you for posting that, got me looking into other panel statements and it seems they are very protective over this topic... As in - some sort of emotional attachment.... :roll: Since the code as written, and their statements in the one you posted, and this one below fly in the face of the rest of article 250. (and all that is holy... )

9-107 Log #4538 NEC-P09 Final Action: Reject (404.9(B))
Submitter: Phil Simmons, Simmons Electrical Services Recommendation: Revise the existing text of the 2008 NEC as follows:
(B) Provision for Grounding. Snap switches, including dimmer and similar control switches, shall be connected to an equipment grounding conductor and shall provide a means to connect metal faceplates to the equipment grounding conductor, whether or not a metal faceplate is installed. Snap switches shall be considered to be part of an effective ground-fault current path if either of the following conditions is met:
(1) The switch is mounted with metal screws to a metal box or metal cover that is connected to an equipment grounding conductor or to a nonmetallic box with integral means for connecting to an equipment grounding conductor.
(2) An equipment grounding conductor or equipment bonding jumper is connected to an equipment grounding termination of the snap switch. Exception to (B): Where no means exists within the snap-switch enclosure for connecting to the equipment grounding conductor or where the wiring method does not include or provide an equipment grounding conductor, a snap switch without a connection to an equipment grounding conductor shall be permitted for replacement purposes only. A snap switch wired under the provisions of this exception and located within reach of earth, grade, conducting floors, or other conducting surfaces shall be provided with a faceplate of nonconducting, noncombustible material or shall be protected by a ground-fault circuit interrupter. Substantiation: This proposal intends to move the installation requirements for grounding switches to Article 250 under the jurisdiction of CMP-5. The construction requirements are appropriate to remain in Article 410.

Panel Meeting Action: Reject Panel Statement: The grounding provisions for snap switches should remain in Article 404. These devices are self-contained and, unlike receptacles, they do not provide a portal for a quasi branch-circuit extension beyond the device in the form of a cord. These requirements have been in this location for many code cycles, and users are accustomed to finding them in their current location. Note also the discussion and panel actions in this cycle regarding Proposals 9-110 and 9-111 for examples of where grounding rules become complicated by the design of some current styles of snap switches with novel internal constructions.
Number Eligible to Vote: 12 Ballot Results: Affirmative: 12

And I would still disagree since they can not know or predict the design or installation situation of every device... And the method of attachment is not a low impedance path for fault current as defined in 250.

I find this VERY interesting.... I will stick to NOT grounded...

 

[paul]

I believe the term should be effectively grounded. I voted no.

 

[guschash]

I says grounded with the ground wire that is attach to the dimmer switch to the the grounded box. 250.146

gus

 

[pudge565]

What is the device yoke "mounted" to?

The words "firmly secured" are clearly describing the word "mounting" - nothing in the picture is "firmly secured" to anything, and if it were - it would be secured to sheet-rock - not the metal box...

Check 404.10.

404.10 Mounting of Snap Switches.

(A) Surface type. Snap switches used with open wiring on insulators shall be mounted on insulating material that separates the conductors at least 13mm (1/2 in.) from the surface wired over.

(B) Box Mounted. Flush-type snap switches mounted in boxes that are set back of the finished surface as permitted in 314.20 shall be installed so that the extension plaster ears are seated against the surface. Flush-type snap switches mounted in boxes that are flush with the finished surface or project from it shall be installed so that the mounting yoke or strap of the switch is seated against the box.

So it seems that as long as the "extension plaster ears" (which I believe is the yoke, correct me if I am wrong.) are seated against the surface of the wall it is compliant.

 

[Jim W in Tampa]

Does this dimmer have a green wire ? If yes then grounded asuming you use it. If no green wire or grd screw the i say not grounded. Can't vote without knowing that.

 

[e57]

Does this dimmer have a green wire ? If yes then grounded asuming you use it. If no green wire or grd screw the i say not grounded. Can't vote without knowing that.

No it does not - no EGC.... Why this thread???? Not long ago I found a bunch little green wires sitting in the trash bucket... Another thread reminded me of that incident....

See MD's post....

The CMP diagrees with you :

If I go with the wording of either the CMP statement he, or the one I posted then there is no purpose for having a green wire, a ground screw or ever grounding a switch EVER AGAIN! EVER!!!! Because seriously - it that is an acceptable method of grounding the yoke, then it can also be assumed it is just as an effective ground fault current path for any plate attached to said yoke..... So - I have changed my mind.... I have learned that the CMP involved with switches has no given a flying hoot about grounding of switches for over 70 years - and nor should I.....

I HAVE THOUGHT ABOUT IT FOR THE REST OF THE DAY DURING SOME OF MY OTHER TASKS.....


Never - Ever - Ground a switch - EVER AGAIN! EVER!!!!

 

[Jim W in Tampa]

The danger i see is if we remove this dimmer from the box and it had a fault with screws removed there is no grounding. And even with the mounting screws there is a chance it might not be grounded. I VOTE NO.

 

[al hildenbrand]

For this hypothetical dimmer (that has no EGC connection), there's nothing wrong with adding a wired EGC between the metal box and either the dimmer or a conductive cover plate.

That's simply doing more than the minimum.

The CMP says the minimum to meet NEC requires less work. . . but, hey, it's fine to do better than the minimum, if you choose to.

But as for the NEC minimum requirement, specifically with respect to this hypothetical example in this Poll, even if there is an EGC pigtail hanging off the dimmer, 404.9(B) 404.9(B)(1) together declare that 250.4(A)(5) is present with just the device screws mounting the dimmer in the metal box, and the EGC pigtail is superfluous. The EGC pigtail from the dimmer could be left dangling inside the box.

 

[e57]

There is nothing hypothetical at all.... Any normal wall-plate would have the yoke just snug to the rock in most situations, and many screw-less style plates would have the yoke about 1/16" off the wall - and once the plate is installed it would still only be only slight tension on the screws holding the yoke in place.... i.e. "loose"....

However - I have seen the light.... There is no reason to ever ground a switch...

The code making panel has spoken from behind the curtain of OZ...

These devices are self-contained and, unlike receptacles, they do not provide a portal for a quasi branch-circuit extension beyond the device......

And...

switches ~ do not form an
element in the extension of a circuit beyond the fixed wiring of a building
or structure. This has been the consistent position of CMP 9 on this point for
at least 70 years

It is clear that - they are not concerned with fault current typical to a shorts circuit due to damage, dielectric breakdown or mishandling in either case, or the many others in which I looked at. Since they feel that the yoke, and therefore the cover, if metal would never be exposed to fault currents, and exempt from article 250!

While I will stick to my guns and say that the switch is NOT EFFECTIVELY GROUNDED - since it is not.... It is a contradiction of 250.4

I will now however, go forward with the new-found knowledge that grounding a switch enclosed in a metal box is not even necessary at all.... Switches are a special case outside of the normal rules of grounding. And since they apparently are of the understanding that it would not be exposed to fault currents - then they are also of the understanding that it would not become energized - and therefore no reason to ground a yoke in a non-metallic box either. (with or without a metal face plate) And this finally explains the placebo solder connected #16 tinned conductor on most dimmers. That said, one might even say this makes it safe to put switches within reach of the shower - and if water-proofed - in it...