AFCI confusion

[charlie]

Re: AFCI confusion

I think we are straining at a gnat and swallowing a camel . . . heard that somewhere.

An occupancy sensor is, by design, a device that will use the grounding system for a circuit return path (trust me). Therefore there will always be current flow albeit to the grounding system.

I suggest the switches, even the ones with indicator lights, are not intended to be, nor are they listed as utilization devices. Therefore, a switch is NOT an outlet . . . period (the intent is to be so authoritative that everyone will bow and scrape and the conversation will be over).

 

[al hildenbrand]

Re: AFCI confusion

We're not worthy! We're not worthy!
-Wayne in Wayne's World

Bow, scrape, grovel.



Ryan, let me extend my Victorian garage cupola light example just a titch further. (I really did have a client that paid me for that dimmed cupola light).

Hypothetically now, imagine a low voltage luminaire with an integral magnetic transformer in that Victorian garage, and a Lutron RadioRA dimmer switch inside the bedroom at the window looking out at the garage. For reasons known best by the engineers at Lutron, the RadioRA magnetic low voltage dimmer needs a neutral for its electronics to "talk" with various remote controllers that may be used to also operate this one dimmer. [Aside]The standard RadioRA incandescant dimmer does not need a neutral[/aside]. All this RadioRA magnetic low voltage dimmer does is control a light in the garage. . .it just allows some additional remote controllers access to itself.

 

[al hildenbrand]

Re: AFCI confusion

Charlie, Charlie B.,

I haven't been able to put this one to rest.

Tom Baker's statement

A switch is installed at an outlet.

has a ring of clarity I haven't been able to shake.

A switch exists, not by itself, but in relationship to what it controls, i.e., the utilization equipment. The utilization equipment takes current through the switch from the switch's connection to the wiring system. An occupant utilizes the equipment by turning the switch on.

When the utilization equipment is on, current is taken from the wiring system on the "hot" side of the switch. The definition of outlet does not say that the current can only go directly to the utilization current without passing through any more wiring system.

 

[al hildenbrand]

Re: AFCI confusion

Article 100

Outlet. A point on the wiring system at which current is taken to supply utilization equipment.
NECH - An example is a lighting outlet or a receptacle outlet.

Utilization Equipment. Equipment that utilizes electric energy for electronic, electromechanical, chemical, heating, lighting, or similar purposes.

An occupancy sensor uses electricity for electronic purposes.

A switch with indicator or pilot light are lighting purposes.

A dimmer uses electricity for electronic purpose.

A timer switch uses electricity for electronic purpose.

It seems to me that these forms of switches go beyond being devices and are, by 100, utilization equipment.

 

[al hildenbrand]

Re: AFCI confusion

Article 100

Outlet. A point on the wiring system at which current is taken to supply utilization equipment.
NECH - An example is a lighting outlet or a receptacle outlet.

Utilization Equipment. Equipment that utilizes electric energy for electronic, electromechanical, chemical, heating, lighting, or similar purposes.

An occupancy sensor uses electric energy for electronic purposes.

A switch with indicator or pilot light uses electric energy for lighting purposes.

A dimmer uses electric energy for electronic purpose.

An electronic timer switch uses electric energy for electronic purpose.

It seems to me that these forms of switches go beyond being devices and are, by 100, utilization equipment.

Please pardon my reposting this edited piece. I was tired last night. . .and, to me, with these changes, the point is easier to read.

Paranthetically, I don't like the point I'm making at all. . .please convince me that the NEC is not saying this.

 

[charlie b]

Re: AFCI confusion

Al: I will concede that the four devices you name can be said to use current in their own rights, as well as passing current along to another device further downstream. (I might argue the dimmer switch, if it is a mere variable resistor with no electronic components.) If you were an inspector on a job that I designed, I also concede that I would lose any argument that I might put forth, to the effect that this is not an ?outlet,? and that 210.12(B) need not apply.

However, if I put forth the same argument with regard to a plain on/off switch, and if you were an inspector that job that I designed, I would still lose the argument , but I would know that I was right.

All in all, I prefer Ryan?s notion, that the thing is ?utilization equipment? if, and only if, it has a neutral. I prefer this, because it sounds a lot like my previous post, in which I mention current leaving the device and heading, not downstream, but back to the source.

 

[al hildenbrand]

Re: AFCI confusion

Charlie B.,

Even a resistor uses electric energy, whether the ends are connected between a hot and neutral, a hot and ground, two hots, with or without additional load in series with it.

I'm not finding the limitation to a neutral in the definition of utilization equipment.

The resistance of wire and connections is inherent to the wiring system, but a resistance inserted as a rheostat is placed there for electronic purpose.

 

[charlie b]

Re: AFCI confusion

Originally posted by al hildenbrand: Even a resistor uses electric energy. . . .

So does a wire, but I think the phrase ?expends electrical energy in the form of heat? might be a bit more precise than ?uses electrical energy.? By this line of reasoning, however, every run of cable constitutes ?utilization equipment.?

I'm not finding the limitation to a neutral in the definition of utilization equipment.

Neither am I. But I don?t think that an item can ?use electrical energy? for purposes of its own, without a complete circuit from the source, to the item, and back to the source. (ASIDE: The return path need not be a neutral ? it could be another phase conductor, as in a 208 volt load.) By contrast, the dimming resistor does not use energy for any of the five purposes listed in the definition of ?utilization,? nor for any ?similar purposes.? It uses energy as an incidental side effect of its only function in life: to prevent the light bulb located downstream from using as much energy. As I said earlier, I might lose this argument with an Inspector, but it would not be the first time.

 

[al hildenbrand]

Re: AFCI confusion

Originally posted by Charlie B.: [A resistor] uses energy as an incidental side effect of its only function in life: to prevent the light bulb located downstream from using as much energy.

The resistor (rheostat) exists in relation to the bulb for the purpose of dimming it. This is electronic purpose. Seems to me. IMO. While the heat generated by the current flowing through the resistor may be incidental, it is using electrical energy none the less, thus completing the definition of utilization equipment.

Originally posted by Al Hildenbrand: The resistance of wire and connections is inherent to the wiring system, but a resistance inserted as a rheostat is placed there for electronic purpose.

 

[al hildenbrand]

Re: AFCI confusion

A dimmer and a luminaire are an example of two different utilization equipment deliberately wired in series with each other.

Originally posted by Charlie B.: I don?t think that an item can ?use electrical energy? for purposes of its own, without a complete circuit from the source, to the item, and back to the source.

I submit that no code provision prohibits the connection of two utilization equipment in series with each other. When supplied electrical energy by the wiring system, both utilization equipment are connected between higher and lower potential and both use electric energy.

 

[al hildenbrand]

Re: AFCI confusion

When a common two wire silicon dimmer switch is inserted in a wiring system on a simple switch loop, the dimmer, being utilization equipment takes current at the point on the wiring system it is connected to. Therefore, the switch is mounted at an outlet.

Kudos to Tom Baker .

The current taken by the dimmer is determined, not by the dimmer alone, but by the dimmer and the load that it controls.

The current taken by the dimmer and its load travels to the load in a section of wiring system.

[ April 01, 2004, 06:20 PM: Message edited by: al hildenbrand ]

 

[tonyi]

Re: AFCI confusion

Some device in series on the hot alone (i.e. black in, black out) would pull power but not be connected directly to the neutral if there were additional downstream loads.

 

[charlie b]

Re: AFCI confusion

Originally posted by al hildenbrand: When a common two wire silicon dimmer switch is inserted in a wiring system on a simple switch loop, the dimmer, being utilization equipment takes current at the point on the wiring system it is connected to. Therefore, the switch is mounted at an outlet.

Sorry Al, but we are going to have to agree to disagree on this one. I will continue to contend that neither a simple on/off switch nor a dimmer switch ?takes current,? and that therefore neither is ?utilization equipment.? I believe that the two words that you and I are interpreting in a different manner are the word ?takes? and the word ?utilization.?

 

[charlie b]

Re: AFCI confusion

Originally posted by tonyi: Some device in series on the hot alone (i.e. black in, black out) would pull power but not be connected directly to the neutral if there were additional downstream loads.

Very true. But the downstream loads would not have the full rated voltage of the system, and it will not just be due to voltage drop along the wires. If you put a switch in series with a light in a home application, then the light will get nearly all of the rated 120 volts. If you put two lights in series, with or without a switch, then each light will get only about 60 volts. I submit that, for the home applications, we install components that are designed to pull a value of current that is based having about 120 volts across the component itself. A 120 volt light is ?utilization equipment,? because it will draw current (and expend power) based on a 120 volt drop across the light. A switch is not ?utilization equipment,? because it drops essentially no voltage by itself, and its 120 volt rating is based on not leaking current to ground at a supply voltage of 120 volts.

Using this reasoning, it is harder (as I have admitted twice already) to justify the position that a dimmer switch is also not utilization equipment. For as the light is dimmed, the switch drops more voltage, and the light gets less voltage. But that is not enough to convince me to change my view. The dimmer controls the voltage to the light, and expends power in its own right, but the thing from which the owner is getting useful work (i.e., ?utilization?) is the light, and not the dimmer. You turn the dimmer and then look at the light, not at the dimmer, to perceive the result of your action.

In any event, I can add no more to this discussion, without repeating myself. So I?ll back away, and let others have their say.

 

[al hildenbrand]

Re: AFCI confusion

Charlie B.

Your description of a dimmer as a voltage control applies to rheostats and full wave dimmers used on magnetic transformers. A common silicon dimmer of the 125 volt 600 watt flavor acts more as a switch, cycling on and off 120 times a second limiting the power let through to the lamp. Energy over time available at the lamp is what determines the intensity of the glow.

The timing of the dimmer is regulated by the manual setting of an electronic trigger circuit. After that manual adjustment, the dimmer electronics use the electrical energy available from the wiring system to operate automatically, electronically.

For the portion of a half cycle that the dimmer is not supplying full voltage to the lamp, the dimmer has full voltage across itself.

For the portion of a half cycle that the dimmer is ON, the lamp has full voltage across itself.

Both the lamp and the dimmer operate at full voltage. . .just not simultaneously.

The electronic purpose of the circuit of the dimmer is to limit the power dissipated at the filament of the lamp. The circuit has to use electric energy to operate.

I know I'm going on and on in this thread. I apologize for any misunderstanding that I'm creating. Please call me on it. I'm trying to be as dispassionate as I can. Charlie, I greatly appreciate your sparring with me over this interpretation. I have, until I started in on this thread, been very happy to use the exception of a switch as something that, by itself, does not fall under the purview of 210.12(B).

I love the freedom to wire the back yard light on a non-AFCI circuit and to be able to put the switch (with a dimmer) inside the bedroom. But the definitions of outlet and utilization equipment rather clearly seem to be saying otherwise, to my dismay.

That said: I repost the Article 100 Definitions:

Outlet. A point on the wiring system at which current is taken to supply utilization equipment.
NECH - An example is a lighting outlet or a receptacle outlet.

Utilization Equipment. Equipment that utilizes electric energy for electronic, electromechanical, chemical, heating, lighting, or similar purposes.

Nothing in the definitions limits the idea of taking of current to be in parallel with the wiring system only.

Nothing in the definitions specifies the voltage that is to be across an equipment before it will become utilization equipment.

Nothing in the difinitions specifies the amount of electric energy that is utilized before the equipment becomes utilization equipment, just that electric energy of any amount is utilized.

[ April 02, 2004, 03:13 PM: Message edited by: al hildenbrand ]

 

[bjansen]

Re: AFCI confusion

The smoke detectors in bedroom will be removed from arc-fault requirements in 2005 code.

 

[don_resqcapt19]

Re: AFCI confusion

bjansen,

The smoke detectors in bedroom will be removed from arc-fault requirements in 2005 code. [/uote]
Can you provide a source for your statement? I don't find anything in the ROP or ROC that would support your statement.
Don

 

[bjansen]

Re: AFCI confusion

I have a good friend who is on Code Panel #3. The decision was made in the comments stage at the December San Diego meetings. It will be finalized in May in Salt Lake City.

 

[don_resqcapt19]

Re: AFCI confusion

This is the panel action from the ROC on the proposed smoke detector exemption from the AFCI requirement.
______________________________________________________________
2-107 Log #1335 NEC-P02 Final Action: Reject
( 210.12(B) Exception (New) )
________________________________________________________________
Submitter: Joseph A. Ross, Ross Seminars
Comment on Proposal No: 2-134a
Recommendation: Add a new Exception No. 3 as follows:
Exception No. 3: AFCI protection shall not be required for permanently installed alarm systems (fire, smoke, and burglar) in dwelling units.
Substantiation: The submitter agrees with the new additions of Exceptions Nos. 1 and 2, but letʼs consider the addition of new Exception No. 3.
Exception No. 1 will permit up to 6 feet of unprotected (AFCI) branch-circuit conductors where installed in a metal raceway or a metal-sheathed cable. This was done more as a convenience to establish a level playing field for the use of receptacle type AFCIs than for safety reasons.
Exception No. 2 will permit an unprotected (AFCI) ?individual branch circuit? supplying a dedicated (marked) outlet for life-support equipment in
dwelling unit bedrooms. An ?individual branch circuit? can serve only one utilization equipment and at least three circuits (PCA pumps, Feeding pumps, Respirators, Beds, etc.) may be needed. This means, that for three such circuits at least 90 feet, on an average, [up the wall (8 ft.), across the ceiling (15 ft.), and down the wall (7 ft.)] (3 x 30 ft. = 90 ft.) may be needed. Consider the use of 90 ft. of unprotected (AFCI) cable (any cable method, not metal raceway or metal-sheathed cable). But, then consider not permitting 3ʼ of cable (of any type) located over the bedroom entry door to supply a life-saving smoke detector. The location above the entry door is virtually free from any physical injury and it is unrealistic to think that a nail, etc. would be driven in that location.
If an AFCI device operates on a bedroom outlet (receptacle or lighting), the worst scenario is to reset the clock radio. A smoke detector is not a bedroom outlet per se, it is a smoke detector outlet located in the bedroom to rouse sleeping families in fire or smoke situations. Smoke detectors are a life-saving device and it is unthinkable to compromise this circuit by connecting it to a sensitive AFCI protected circuit.
Panel Meeting Action: Reject
Panel Statement: The submitter has not provided Panel 2 with any documentation to support his claim that AFCI devices are not compatible with listed smoke or burglar alarms.
Number Eligible to Vote: 13
Ballot Results: Affirmative: 10 Negative: 3
Explanation of Negative:
BECKER: See my explanation of negative vote on comment 2-70.
DOBSON: With AFCI technology still in its infancy it is clear there are many uncertainties. The CMP has decided to redefine the technology because
it does not supposedly provide all of the desired protections. The CMP has decided to hold off on any expansion of the device in new construction until
enough field data has been provided. We do not know everything about AFCI technology and how it will perform. There is enough skeptisism to warrant not taking a chance on having the AFCI technology impede the performance of a proven technology that has been around for well over 30 years. We should not compromise the single most important fire safety device in one-and-two family dwellings - smoke alarms. This requirement not only impacts the smoke alarms in the bedrooms but also will effect the entire smoke alarm system, as interconnected smoke detectors are required by manufacturers to be wired on the same circuit.
OʼNEIL: The panel has rejected this comment because the submitter has not provided substantiation that AFCIs are not compatible with listed alarms.
Manufactures have submitted that current product standards does permit nuisance tripping on products listed to UL 1699-1999. Until any question of the possibility of nuisance tripping is resolved, AFCI devices should not be permitted on life saving devices. Putting AFCI protection on Life Safety devices creates the greater risk of disabling life saving devices at the time proper operation of the life-safety device is most required.

[ April 05, 2004, 12:25 PM: Message edited by: don_resqcapt19 ]

 

[charlie b]

Re: AFCI confusion

Originally posted by al hildenbrand: Your description of a dimmer as a voltage control applies to rheostats and full wave dimmers used on magnetic transformers. A common silicon dimmer of the 125 volt 600 watt flavor acts more as a switch, cycling on and off 120 times a second limiting the power let through to the lamp.

I think this is another detail in which we have differing opinions. I would not call a common dimmer switch ?electronic,? any more than I would call a fixed value resistor, or even a wire, ?electronic.? The statement of yours that I quote above contains the point of distinction. Once you alter the nature of a sine wave, by performing any switching on a ?part cycle on, part cycle off? basis, then you are definitely into electronics. Resistors, even variable resistors, are used in electronic systems. But that does not make the individual resistor an ?electronic component? of the electronic system.

The McGraw-Hill Dictionary of Scientific and Technical Terms defines ?Electronic? as

Pertaining to electron devices or to circuits of systems utilizing electron devices, including electron tubes, magnetic amplifiers, transistors, and other devices that do the work of electron tubes.

This same book defines ?Electron Device? as

A device in which conduction is principally by electrons moving through a vacuum, gas, or semiconductor, as in a crystal diode, electron tube, transistor, or selenium rectifier.

A variable resistor (i.e., dimmer switch) does not meet either of these definitions. Therefore, </font>

• <font size="2" face="Verdana, Helvetica, sans-serif">A dimmer switch is not an electronic device,
  
  A dimmer switch fails to meet the definition of ?utilization equipment,? and
  
  A box that houses a dimmer switch fails to meet the definition of ?outlet.?
  
  QED.</font>

<font size="2" face="Verdana, Helvetica, sans-serif">