Parallel path's??

[iwire]

You will find that most light switches that are internally illuminated when the switch is off, do the same thing.
I'm not sure of the code implications.

Ron those usually operate by running the current through the load, not the EGC. :smile:

 

[iwire]

Pull the lighting circuits' neutral to the switch and use the proper wire to power the switch.

That would also be a violation.

 

[GMc]

Charlie,

I appreciate the response but I have to say I'm confused.

Now the question of Code enters the minds of most of you. Consider that it is a listed device in the same manner as devices that have more load than they should have to be plugged into a 15 ampere receptacle and they are listed with a 15 ampere plug. Because the device is listed and used in a manner consistent with the manufacturer's instructions, it is fine and does not violate the NEC. The products have been tested and no danger has been found.

Why is it that manufacturers can design devices like you mentioned and as long as they provide instuctions they are covered even though the NEC says you can't do it? Shouldn't the NEC have a fpn stating "Unless it's UL approved"?

When you and I wire anything it has to be idiot proof and sized correctly. We can't just leave instructions saying follow these instructions and you will be safe.

Sorry, I just don't get it. Just trying to understand.

Thanks to everyone for all the responses,

Gary

 

[ELA]

This is an interesting thread and I am surprised that someone didn't know that UL does permit this type of construction.

Well now we do.
Can you enlighten us a little further as to what the exact criteria for allowing this are?
Is it allowed no matter what the purpose for the leakage and is it up to the 500ua level or some other value?

Oviously this conection must be disconnected when they perform any UL mandated Hi-Pot test.

 

[charlie]

Gary, I wish I could help more but I don't have the answers you are seeking. I have heard the UL Representative at several IAEI meetings give the same answer to this type of question. None of the other Code "experts" have ever questioned his answer.

By the way, UL doesn't approve anything but they include items in a list. Therefore, they get a UL or more appropriately, a NRTL (Nationally Recognized Testing Laboratory and it is commonly pronounced, "nert'-el")listing. :smile:

 

[Pierre C Belarge]

Charlie,

I appreciate the response but I have to say I'm confused.



Why is it that manufacturers can design devices like you mentioned and as long as they provide instuctions they are covered even though the NEC says you can't do it? Shouldn't the NEC have a fpn stating "Unless it's UL approved"?

When you and I wire anything it has to be idiot proof and sized correctly. We can't just leave instructions saying follow these instructions and you will be safe.

Sorry, I just don't get it. Just trying to understand.

Thanks to everyone for all the responses,

Gary

I concur with what Charlie has posted.



The reason the manufacturer can provide this type of device and we in the field cannot install to the same conditions is relatively simple.
The manufacturers build and have TESTED their product in a factory and controled environment.
We in the field do not have a NRTL testing our installations and the different environments we work in cannot be controlled, therefore our installations may not be as consistant as the results a manufacturer can produce.

 

[ELA]

I would still like to know what the acceptable leakage to ground level is considered to be when such devices are evaluated. Also is it is the same regardless of the reason for the leakage.

Emi filters leak a fair amount and that is not intentional. It is a byproduct of providing EMI protection at higher frequencies.
When a manufacturer purposely leaks current to ground to power their device is this allowed at the same level.

The device mentioned here was only 0.7 uamps. Can a device purposely leak up to 500uA to ground for their use? If so then it would only take 12 of these devices to trip a GFCI. I wounder if this practice should be of concern -if every manufacturer were to begin taking advantage of it?

 

[GMc]

I would like to understand it better also.

I know the current to ground from these switches isn't going to kill anyone. You wouldn't even feel a tingle but thats not my point. Manufacturers can just as easily design the products to use the neutral (like most of us have to).

I wonder how many of these switches they would sell to the commercial world if they required a neutral at the switch? I would guess a lot less of them. It's not right they do it intentionally.

I know, like ELA has mentioned, that equipment and devices have leakage current to ground but it's not intentional.

I want to thank everyone for taking the time to respond to this thread.

ELA,

When I was playing with the switch on the bench I noticed the current to ground raised to 1.3ua when the switch was turned on.

I'm trying to remember the leakage current allowed on equipment in patient areas of a Health Care Facility. It's been a long time since I've done safety checks. I'm thinking it is less than 500ua but maybe not.

Gary

 

[don_resqcapt19]

UL knows that they made a mistake in the listing of products that use the EGC as a current carrying conductor and are often behind the proposals to require a grounded conductor at a switch box. That being said, there is nothing in the UL listing process that changes the NEC rules and the listing does not permit the listed product to put normal operating current on the EGC. That conductor is only permitted to be used to connect the normally non-current carrying parts of the equipment to the grounded conductor. I would red tag that device every time if I was inspecting.

 

[ELA]

there is nothing in the UL listing process that changes the NEC rules and the listing does not permit the listed product to put normal operating current on the EGC.

Don, Can you please explain in a little more detail?

The switch in question was posted as:
http://www.wattstopper.com/getdoc/342/15204TS-400.pdf


Are you saying that even though they claim to be UL listed that they are in violation of the NEC?
Are you saying they should not be allowed? I am not up to speed on the NEC. My most recent copy is 2005. What section would you site to disapprove these devices?

I find this most interesting ...

 

[peter d]

If the current is 0.7 micro amps as the OP stated, then who cares? I don't.

 

[don_resqcapt19]

ELA,
That one appreas to get its power through the load and would be ok with the NEC. There are simular products that use the EGC as part of the power supply and are UL listed. It is my opinion that the use of any product that uses the EGC as a circuit conductor is a violation of the NEC, UL listed or not.

 

[GMc]

ELA,
That one appreas to get its power through the load and would be ok with the NEC. There are simular products that use the EGC as part of the power supply and are UL listed. It is my opinion that the use of any product that uses the EGC as a circuit conductor is a violation of the NEC, UL listed or not.

I'm confused. As stated in a previous post the switch will not work without the EGC connected. One might not tell that from looking at the schematic in the link I posted. You can take the load off the switch and it will operate as long as you have 120-277v and the EGC connected.

Thanks for the interesting information.

If the current is 0.7 micro amps as the OP stated, then who cares? I don't.

Obvivously I care. :grin: The code doesn't say that I can use the EGC as a current carrying conductor if the current is low enough that it wouln't hurt anyone. I like to try and follow the NEC as best I can.

Gary

 

[peter d]

I
Obvivously I care. :grin: The code doesn't say that I can use the EGC as a current carrying conductor if the current is low enough that it wouln't hurt anyone. I like to try and follow the NEC as best I can.

I care about NEC compliance too, but this is one situation that I'm not going to worry much about. The danger appears to be so low as not to be an issue.

 

[GMc]

The issue I have is that Manufacturers are designing products that the NEC says we can't use. So what if more and more Manufacturers do the same thing. Maybe it would be a problem then. Who's going to say enough is enough.

Another thing is I've been taught one way for years only to find that it's common practice. I guess I've been blind to this fact.

Gary

 

[K8MHZ]

What's even more confusing is the diagram to use the switches as three-ways.

Explanation please???

 

[K8MHZ]

I just got off the phone with Tech Support at Wattstoppers.

UL allows up to 500 micro amps on the grounded conductor but Rick, the Tech guy, could not find an NEC allowance. He indicated to me that he will do some more checking and get back to me with a response via e-mail.

I also recommended for him to get an account here for both questions and answers and he responded favorably.

So far, it looks like using the grounding conductor to return small amounts of current is UL approved as per UL 943, 508 and 1472 but not addressed by the NEC. All that is addressed in 250.6 is 'objectionable current' and 'objectionable' is not defined. Perhaps it is such that UL approved leakage current is not considered 'objectionable' by the NEC but there is no verbiage to back that up.

Rick also explained the function of the switches used in a 3 way configuration. They cannot be used as three ways manually, instead rely on timing out as they are simply wired in parallel.

 

[don_resqcapt19]

It is my opinion that the definition of EGC prohits this use.

Grounding Conductor, Equipment. The conductor used to connect the non–current-carrying metal parts of equipment, raceways, and other enclosures to the system grounded conductor, the grounding electrode conductor, or both, at the service equipment or at the source of a separately derived system.

 

[K8MHZ]

It is my opinion that the definition of EGC prohits this use.

The definition just says what it can be used for. It does not address what it can't be used for. The term 'shall not' is not in the definition, nor is 'prohibits'.

That brings us back to 250.6

 

[crossman]

But the catch is....

We are using a conductor as a current-carrying conductor which carries current required to operate a device. Wouldn't that conductor now fit the description of either an ungrounded conductor or grounded conductor? And that conductor must comply with rules for said conductor?

In this case, the conductor carrying the load current required by the electronics of the device is actually a neutral? And neutrals (grounded conductors) certainly can't be green or a run of EMT.