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Posted By: sparky PFCI ? OFCI ? - 06/30/10 06:01 PM
No technology located in a circuit breaker or fuse panel could detect a high-resistance wiring fault, as no measurable characteristic exists that differentiates a glow fault from normal branch circuit operation. Power Fault Circuit Interrupters (PFCI) located in receptacles are designed to prevent fires caused by glowing connections in premise wiring or panels. From the receptacle, a PFCI can detect the voltage drop when high current exists in a high resistance junction. In a properly designed circuit, substantial voltage drops should never occur. Proper wire terminations inside utilization equipment (e.g. appliances, lamps, heaters) and cords prevent high-resistance connections that can lead to fires.

Excess current can heat entire lengths of wire. Thermal circuit breakers are designed to protect against excess current through the permanent circuit wiring. However, excess current through the smaller wires in utilization equipment can exist, at levels below the trip thresholds of a circuit breaker. Overload fault circuit interrupters (OFCI) are designed to protect against excess current drawn by utilization equipment. OFCIs must be located within receptacles. Both thermal circuit breakers and OFCIs are required to prevent fire ignition from excess current.


from wiki>
http://en.wikipedia.org/wiki/Arc-fault_circuit_interrupter


anyone ever heard of, or seen these devices ?

~S~
Posted By: HotLine1 Re: PFCI ? OFCI ? - 06/30/10 07:31 PM
~s~:
I recently saw something about a device (Duplex recept) that had some overload protection as selling point.

I can't remember where...possibly the 'lectricians toolbox site that I went to out of boredom! I looked thru recent posts here & do not see the thread.

It featured a 'glowing' termination on a screw terminal of a recept if I remember.

Later
Posted By: Bill Addiss Re: PFCI ? OFCI ? - 06/30/10 09:04 PM
Originally Posted by HotLine1
~s~:
I recently saw something about a device (Duplex recept) that had some overload protection as selling point.

I can't remember where...possibly the 'lectricians toolbox site that I went to out of boredom! I looked thru recent posts here & do not see the thread.

It featured a 'glowing' termination on a screw terminal of a recept if I remember.

Later
Is this it?

http://www.electrical-classifieds.com/27_fire_prevention_outlet
Posted By: HotLine1 Re: PFCI ? OFCI ? - 06/30/10 09:37 PM
Bill:
You do not cease to amaze me!!!

That's it!

Check it our Sparky
Posted By: renosteinke Re: PFCI ? OFCI ? - 07/01/10 01:09 AM
Just a caution ....

The "UL" listing is just for the device as a receptacle. UL has NOT evaluated the claimed protective features of the device.

Nor, for that matter, are they likely to ... until the technology is completely free from an patent/trademark protections, and the NEC recognizes it.

If that ever happens, I'll let you know ... I "know someone" on the appropriate committee.
Posted By: sparky Re: PFCI ? OFCI ? - 07/01/10 01:40 AM
Originally Posted by HotLine1
Bill:
You do not cease to amaze me!!!

That's it!

Check it our Sparky


Nor I...good shootin' Bill

Fact is, i'm rather fascinated Hotone, enough that i called a one Mr. Michael Strauss, Chairman & CEO (well i called and he was kind enough to call me back promptly) inquiring as to his new product

link here

One might recall the point of use debates that circulated when the afci debuted....


The interesting thing is, this product, apparently predicated itself via Joule's first law of thermodynamics>

Product DescriptionThis device consists of multiple sensors which detect abnormal heat at each outlet contact and binding head screw terminal. When such heat is detected, the sensors activate, the load fully disconnects, and an indicator pin protrudes from the face of the device. The user can easily see that abnormally high heat activated the device, which is no longer functional – a feature that prevents further damage to the existing wiring. We recommend that a licensed professional inspect the fault condition and replace the outlet.

So, instead of having Mr. Strauss spend his time answering to just one electrician, begging the induldgence of the moderators ,i've asked him here to explain it en masse' (and Mike, if you can sell this crew, your in like flint!)


~S~

Posted By: Trumpy Re: PFCI ? OFCI ? - 07/01/10 01:49 AM
Just a little thing about terminations at fittings themselves.
Now I'm not trying (or willing) to put the boot into the way things are done in the US, but I've never really liked the idea of the "wire under the screw" method of connecting a wire to a device.

Having said that, I don't have a problem with it per se, where an electrician that does heaps of these connections every day of the week and can just about do it with their eyes closed and with the proper tools.

But, when you get someone doing their own electrical work at home, there is a chance the copper could be nicked or some of the copper wire stripped away, resulting in a lower integrity connection with the screw and a higher resistance connection.
Or you have the person that winds the wire around the wrong way and it moves out from under the screw as it is tightened.
For this reason alone, I prefer the tunnel type terminals we use over here, they are virtually fool-proof.

I do however, like the concept of the receptacle that Bill linked to, a LOT of energy is dissipated at bad connections.
Posted By: HotLine1 Re: PFCI ? OFCI ? - 07/01/10 02:59 AM
Trumpy:
FWIW, we have 'tunnel' terminations on devices here, on 'specification grade' devices.....which are premium $$ priced. They always were my 'choice', and were great with stranded conductors. Keep in mind also on this corner of the world, the NMC is solid conductors.

Posted By: Bill Addiss Re: PFCI ? OFCI ? - 07/01/10 04:09 AM
Originally Posted by HotLine1
Bill:
You do not cease to amaze me!!!

That's it!

Check it our Sparky
LOL!

Well, maybe some disclosure is appropriate here....

I've got one on the desk in front of me. smile

It's a local company and I was approached about possibly selling them last year.

Bill
smile
Posted By: HotLine1 Re: PFCI ? OFCI ? - 07/01/10 04:34 AM
Disclosure? I'm looking at a bottle of ice tea that's empty & a clock that says it bed time!
Posted By: Texas_Ranger Re: PFCI ? OFCI ? - 07/02/10 12:39 AM
Sounds like the thermal protection they've been using in extension cord reels here for 20+ years built into a regular receptacle. Basically a thermocouple.
Posted By: noderaser Re: PFCI ? OFCI ? - 07/03/10 08:04 AM
Did I read correctly that this is a disposable, one-time device? Sounds like a way for someone to get rich replacing them, without actually solving the underlying problem(s).
Posted By: renosteinke Re: PFCI ? OFCI ? - 07/03/10 04:15 PM
I have also noted the sale of "Safety" extension cords. As I understand it, these cords have an inner foil wrapping that is intended to let the cord 'detect' damaged conductors.

I have to applaud the manufacturers for at least trying. Still, technology is no substitute for either care or competence.

The cynic in me fears another motive -profit by manpulating the legal/political worlds - but that's another topic, for another day. Maybe some of these guys really do care about safety.

As for the device being a 'one time only,' just think of it as another "Fixed User Safety Element," or FUSE for short. Or shorts. Whatever.

Just what is safety, after all? Would not the safest house be one with no power at all? Yet, our codes require the introduction of this hazard.

OK, that's a bit extreme .... but think for a moment ... just how many of our new code requirements address risks introduced by previous requirements? Perhaps the best example is the AFCI, which was advertised to address the pinched cord from the receptacle that was behind the bed's headboard .... and that outlet's placement was directly caused by using the '6 ft. rule' as a design principle. We started the code saying 'this is not a design manual,' then a few pages later deliver a design rule on a silver platter.

Heat at the point where the plug enters the receptacle, or an apliance using too much power. Would these concerns not be more easily, and accurately, addressed by simply putting a fuse in the plug?
Posted By: sparky Re: PFCI ? OFCI ? - 07/06/10 08:20 AM
Quote
OK, that's a bit extreme .... but think for a moment ... just how many of our new code requirements address risks introduced by previous requirements? Perhaps the best example is the AFCI, which was advertised to address the pinched cord from the receptacle that was behind the bed's headboard .... and that outlet's placement was directly caused by using the '6 ft. rule' as a design principle. We started the code saying 'this is not a design manual,' then a few pages later deliver a design rule on a silver platter.


well Reno, the point you raise could be viewed as the NEC being self correcting, which really is about as much so as any other faction of the market

Quote
Heat at the point where the plug enters the receptacle, or an apliance using too much power. Would these concerns not be more easily, and accurately, addressed by simply putting a fuse in the plug?


i would think addressing point of use would be more efficent than relying on a devive that could be any given length away , especially if the problem IS at the user end

even something as simple as the method of termination , which seems to be, by grace of our foriegn corespondends something less apreciable a design

wag the dog eh?

still, i'm interested in these aforementioned devices, do they exist? has a manufacturer actually produced and marketed them? what does UL say?, etc

~S~
Posted By: renosteinke Re: PFCI ? OFCI ? - 07/06/10 01:27 PM
I think I can guess UL's position. It would go something like this:

"UL tests to nationally recognized standards, and does not endorse any particular brand or technology. UL is not prepared to offer any opinion on this particuler product. Indeed, UL simply will not cerify any 'proprietary' product as being 'safer' than its' competetors. For example, UL refrained from developing a standard for AFCI's until after the owners of the patent donated it to the public domain. The only monopoly we would ever endorse would be our own."
Posted By: sparky Re: PFCI ? OFCI ? - 07/06/10 11:27 PM
well one can draw thier own conclusions Reno...>



Quote
Follow-Up Services Council
Formed in 1976, the council provides expertise and assistance to UL in appropriately maintaining its current inspection and market surveillance programs and in the development of new follow-up services, surveillance and inspection programs. Individuals representing manufacturers, retailers, professional societies, trade groups, distributors, insurance, government and academia compose the group.


http://www.ul.com/global/documents/secured/councils/Council_guidelines.doc


myself, i'd like a little more of the exact parameters of these devices, and the methodology that led them to do so

i don't really think that's a lot to ask, is it?

~S~
Posted By: renosteinke Re: PFCI ? OFCI ? - 07/07/10 12:18 AM
Please, be very, very careful about trying to 'read between the lines' when it comes to UL. When they say they have no opinion, that's just what it means: no opinion. Do not infer that they approve, disapprove, or anything else.

A similar issue comes up when folks try to infer quality from the presence of a UL lable. Some completely useless kludge has passed the appropriate UL safety standards, without being able to perform the intended function at all. (A certain 'surge suppressor' that you slipped over the prongs of a plug comes to mind).

We've seen a number of instances where private parties attempted to corrupt the code-writing process for their own private gain. At least two such cases have made it to the US Supreme court. With that in mind, perhaps we can understand UL's refusal to endorse any proprietary technology.

Likewise, how you 'test' something is always a concern. Let me arrange the test, and you can be sure my product will shine. Absent a 'standard test,' just what do test results really mean? That is why I pointed out that the UL lable only inferred that the product was evaluated to standard tests, and not any sort of validation as to the 'special' features of the devices.

For all I know, it's a marvelous invention. I remember the furious debates over new technology in the past .... GFCI's, power factor correction, even over the "Ufer." (Heck, my co-workers continue to debate the effectiveness of the Ufer!) I also remember some 'great advances' that fizzled ('Streamer Emission' lightning receptors, anyone?)
Posted By: sparky Re: PFCI ? OFCI ? - 07/07/10 12:28 PM
Quote
Please, be very, very careful about trying to 'read between the lines' when it comes to UL. When they say they have no opinion, that's just what it means: no opinion. Do not infer that they approve, disapprove, or anything else.

Not overtly, seems inviting in just about anyone remotely connected for their $.02 amounts to a formulated opinion they may act on though....


Quote
A similar issue comes up when folks try to infer quality from the presence of a UL lable. Some completely useless kludge has passed the appropriate UL safety standards, without being able to perform the intended function at all. (A certain 'surge suppressor' that you slipped over the prongs of a plug comes to mind).

We've seen a number of instances where private parties attempted to corrupt the code-writing process for their own private gain. At least two such cases have made it to the US Supreme court. With that in mind, perhaps we can understand UL's refusal to endorse any proprietary technology.


One can open the first few pages of the NEC to view the movers and shakers Reno, seems to me it works much like the continual stream of ex-Congresscritters turned lobbyists. And hey, we've the best Congress $$$ can buy!


Quote
Likewise, how you 'test' something is always a concern. Let me arrange the test, and you can be sure my product will shine. Absent a 'standard test,' just what do test results really mean? That is why I pointed out that the UL lable only inferred that the product was evaluated to standard tests, and not any sort of validation as to the 'special' features of the devices.

Well first off, it's always convienet to create a standard where there was none. One can obviously move the goal posts as required, Second here is the ever famous flying pig perception created when the actual parameters of tests are given a spin by the manufacturer's marketing , which given mere subtley of inexact vernacular can assume grandious misunderstandings....

Quote

For all I know, it's a marvelous invention. I remember the furious debates over new technology in the past .... GFCI's, power factor correction, even over the "Ufer." (Heck, my co-workers continue to debate the effectiveness of the Ufer!) I also remember some 'great advances' that fizzled ('Streamer Emission' lightning receptors, anyone?)

We were privy to specifics of performance on those items . Less than this isn't something i see a trade of class A personalities with an OC penchant for inquiring to the ninth degree tolerating for very long

~S~
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