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Old 11-11-2007, 10:54 AM   #16
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Quote:
Would a GFCI with a higher trip current rating serve the same purpose as an AFCI?
I, like yourself, am not an electrician, but I think a GFCI has a lower trip current than a AFCI, as it's purpose is to save lives and AFCI purpose is to save property...but again, I'm not an electrician. Stubbie? Andy?...MD?...anyone...

Quote:
Is the potenial for a loose connection the reason most electricians say use the screws on a wiring device not the slip in connections?
I'd say that's the reason, yes. That's MY reason, if nothing else.

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Old 11-11-2007, 07:55 PM   #17
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I do mostly commercial electrical work and so have not had to work with AFCI's often. They do protect against very different fault conditions. A GFCI will protect against current leaking to ground at around 10 mA. I have no idea what amount of current it would take to trip an AFCI, but as an arc fault it seems like it would have to be higher. Frenchy? You seem like you would be the AFCI guy, or do they not require them in Canada?
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Old 11-11-2007, 08:07 PM   #18
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I don't think my French buddy is from Canada. I think he is from France.

GFCI 4-6 mA

AFCI As much as 50A for Branch feeder types. The juries still out as far as I know for the combo type.
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Old 11-11-2007, 08:09 PM   #19
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Goose : let you know that i am in wisconsin and we still on the old 05 code but make one pretty dramtic change that time sans AFCI but myself i think it will really will change anyway.,,

ok get into this topic of a moment " AFCI "


the AFCI will sense both parallel and series fault but IMHO still kinda pretty new around here so i will keep my comment to the facts for now.

the AFCI will sense any current inbalance over 30 MA [ if that is correct ] unless you have one breaker it is made by one company they have it in combo verison [ AFCI / GFCI ] breaker set up.

the AFCI still have some quriks but getting better on next generation of AFCI's

but right now i dont have very strong option with the AFCI's it kinda remind me of the european verison of AFCI what we called RCD and some case it really stink [ dont work right ]

But to be fair with other i will let other join in here who allready have more experince with the AFCI devices.

Merci , Marc
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Old 11-11-2007, 09:22 PM   #20
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AFCI's are going to prevent fires, that much I'm sure of. When an arc occurs due to a loose connection, the arc has no reference to ground, so a GFCI is unable to detect. The combination type hopefully will work as promised. Where they would do the most good is in older homes, where unfortunately they won't be utilized.

I'm gonna let this thread continue for a few more days, and I'll explain my opinion and the opposing opinion, hopefully Stubbie and HH and JV and my French buddy and all the other pros will jump in as well. Goose doesn't count because he's from Chicago which may as well be Mars as far as residential wiring is concerned. Just kidding.
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Old 11-11-2007, 09:29 PM   #21
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Quote:
Originally Posted by Andy in ATL View Post
When an arc occurs due to a loose connection, the arc has no reference to ground, so a GFCI is unable to detect.
Andy, I am surprised you wrote this. I think you know a ground has NOTHING to do with a GFI's functioning.
A GFI monitors the current in and out of the circuit. If the arcing is to ground then yes, it has some bearing, but only since the arcing is causing current to flow to ground, or more accurately the "grounding condcutor". If the arc were to be across the hot and neutral the GFI would not trip.
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Old 11-11-2007, 09:30 PM   #22
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Oh, and a switch is NOT an outlet.
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Old 11-11-2007, 09:43 PM   #23
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Originally Posted by Speedy Petey View Post
Andy, I am surprised you wrote this. I think you know a ground has NOTHING to do with a GFI's functioning.
A GFI monitors the current in and out of the circuit. If the arcing is to ground then yes, it has some bearing, but only since the arcing is causing current to flow to ground, or more accurately the "grounding condcutor". If the arc were to be across the hot and neutral the GFI would not trip.
A grounding wire has nothing to do with the effectiveness of a GFCI. A GROUNDED conductor has everything to do with it. A GFCI WILL NOT protect against a series arcing fault because there is no reference to either the grounded circuit conductor or the equipment grounding conductor. Is that better??? By loose connection... I meant like in a switch.

Edit to add... Grounded conductor has nothing to do with it either... brain fart.

Last edited by Andy in ATL; 11-12-2007 at 05:14 AM.
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Old 11-11-2007, 10:28 PM   #24
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Ok, 6 years ago, when I was living in a condo (my first real estate purch), I started to do some painting in my bed room. After I removed all the switch and recept covers, I went around taping all the devices. One of the recepts was lopsided and had been since I moved in so I decided to straighten it out. POP, ARC, SIZZLE, <poof of smoke>. I look over and the alarm clocks are still OK (no batteries and yes they were not wind-up, ok?! ). I examine things a bit further and notice that the hot had chaffed on the plaster ring and what I experienced was an honest to goodness arcing fault whose impedance was such that it did not trip the CB. So, I can appreciate the concept of an AFCI.

Here in Oak Park, Illinois (just outside of Chicago), they recognize the 2003 NEC (amazing. A bit behind, arent' we??). Being an electrical professional who is certainly cognizant of the NEC but does not deal with the it everyday, if I'm not mistaken, AFCI's were first req'd in the 2005 code and only for bedrooms in dwelling units. Of course I always wondered, based on my experience why they weren't required for every branch circuit. I mean, if the AFCI can trip the circuit before a fire starts in a bedroom, this is great. But if the fire starts in the hallway just outside the bedroom (due to an arcing fault) because arc fault protection is not required here, isn't the occupant in the bedroom still in danger? Anyway, I digress.

In response to Andy's initial question, I would say that, it depends. The lights are on the front and rear of the house. The 3-way switch is in the bedroom with a 3-way at the front and a 4-way at the rear of the house. Let's assume that everything is run in conduit. The box where the bedroom 3-way is located has 2 travelers and the switched hot. We know that at least one of the travelers is always hot and there is a potential for arcing fault to the box (ground), other traveler or switched hot. I'm not an authority on AFCI operation, but I do know that they are similar to GFCI breakers in that they have a terminal for hot and a second for neutral. The wiring configuration allows for the potential (no pun) of arcing fault to ground. If the AFCI would trip for an arc fault to ground then I would say that it is required in this case. If a high-Z cross was created from traveler to traveler then the unit could not detect it. If a high-Z fault occured from hot traveler to switched hot, then this really does not create a problem necessarily as the load (lights) would absorb the fault current and would simply flicker (boy, that would scare the riff raff!). In this last instance though, I guess I wonder as to if this would present a fire hazzard.

(I did read about AFCI's some time ago and I thought that, unlike a GFCI which simply senses the difference between hot and neutral current (and trips on a 5 mA difference), the AFCI actually looks for a current waveform that is characteristic of an arc fault. This may explain my thinking herein.)

Now let's assume the same arrangement wired with romex/NM and plastic boxes. The hot traveler faulted to box or stud may be too high of a resistance to ground to cause any heart ache (I'm admittedly not sure of the resistance to ground of dry pine framing lumber). The other possibilities discussed above are the same.

At any rate, I would assume that, to meet the intent of the code, the circuit should be in fact AFCI protected. Then again, the NEC can be so nebulous that sometimes, I think it was written by lawyers (can't they just say what they mean??!). See Stubbie's explanation of "outlets" if you don't believe me.

Mike Holt rules!

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Jimmy
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Old 11-12-2007, 01:43 AM   #25
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Ok...... My opinion is a switch or switch box is not a point on the branch circuit that was intentionally installed to be used for the connection of utilization equipment in the bedroom and does not meet the definition of an outlet, therefore Andys 3-Way in the bedroom does not require AFCI.

Reasoning

ART. 210.12 (B)

All 120 volt single phase 15 and 20 amp branch circuits supplying outlets installed in a dwelling units bedroom shall be protected by a listed afci combination type.


First lets start at Art. 100 NEC definitions


1.) Outlet..... A point on the wiring system at which current is taken to supply utilization equipment.

2.) Utilization equipment .... Equipment that Utilizes electric energy for electronics, electromechanical, chemical, heating, lighting or similar purposes.

3.) Branch Circuit ... the circuit conductors between the final overcurrent protection device protecting the circuit and the branch circuit outlet(s).

4.) Device ... a unit of an electrical system that is intended to carry or control but not utilize the electrical energy

5.) Disconnecting means ... a device or group of devices or other means by which the conductors of a circuit can be disconnected from the source of their supply.

6.) Lighting outlet.... obviously an outlet

7.) Receptacle ..... A receptacle is a contact device installed at an outlet for the connection of an attachement plug

8.) Receptacle outlet ... obviously an outlet

Now these are some of relative definitions... of course other articles use terms like heating outlet and so forth.

Switch is defined six times in article 100 none of those definitions refer to it as an outlet. However it is refered to as a device and it definitely fits the definition of a device and/or a disconnecting means. Notice that a device does not utilize electrical energy. Art. 210.12 (B) requires a point on the premise wiring system (branch circuit) that you can take energy to supply utilizing equipment. You can't do that at a switch.

Now lets look at a lighting outlet that has the switch on the fixture and hardwired to the electrical box. The electrical box is the end point of the branch circuit conductors ( please read the definition for branch circuit) Where the branch circuit conductors end can be an outlet if it is a point where you can supply energy to utilizing equipment like appliances. Branch circuit conductors don't end on switches they end at the point of utilization of energy

Same logic for a switch receptacle combination. You don't take the electrical energy from the switch. For that matter you don't take it from the receptacle as it to is a device and does not utilize electrical energy. It does however carry the load and provides for the point of connection to supply electrical energy to utilizing equipment. This point on the branch circuit becomes an outlet. A switch does not do this in any way shape or form. It is not the switch in the box that defines the requirement for AFCI. Even if Andy's 3-way were in a box with a receptacle installed on a branch circuit serving that bedroom therefore making that box an outlet it would not require AFCi but the receptacle obviously would because it provides a point of connection to its branch circuit conductors.

Remember that 210.12(B) requires branch circuits serving outlets in the bedroom. His branch circuit for the 3-ways does not serve an outlet in the bedroom, unless the switch is an outlet.

This is the diagram from the ul link i posted earlier showing point of use combination afci on the first outlet protecting the downstream outlets on its load side... anybody see any switches on that branch circuit..take notice there is a light.... so why isn't the switch shown? They show the light but not the switch hmmmm wonder why??? Cause a switch isn't an outlet. They are only showing the required protection points of utilization or in other words the outlets.


Now look at NEC....404.2 (A)... 3-Way and 4-Way switches shall be wired so that all switching is done only in the ungrounded conductors between the switches and their outlets. Obviously the NEC does not consider the switch an outlet. Remember the switch as defined by the NEC is a device and a device is defined to not utilize electrical energy. So the switch in itself cannot define the point on the wiring system where you can connect utilization equipment. A receptacle box does or a lighting box does or a fan box does, any point (electrical box) on the branch circuit that was installed to connect utilization equipment to the branch circuit conductors is an outlet box.

Now lets look at the definition of Branch circuit ...notice the NEC definition says outlet or outlets. So lets just say since Andy's switch is in the bedroom in a box by itself we have to prove it is an outlet to require it to have afci. Otherwise this is a simple deal and the question isn't worthy. Lets say the branch circuit serves that switch only, the branch circuit conductors end in Andys switch box in that bedroom and go nowhere else. Unless it is an outlet it does not require afci by code. Same problem only different set up. Now it should be obvious that you can't utilize energy from that switch. The switch is a device...devices don't utilize electrical energy by definition. So i did not install an outlet in the bedroom with the intent to plug in or use energy consuming appliances or other units.

The outlet is the light box or fan box or heater box where the utilization equipment taps the branch circuit conductors to use the electrical energy. This can be either through a contact device like a receptacle or hardwired to the branch conductors in an electrical box like a ceiling light or ceiling fan. sconce, etc...

Its not the receptacle or switch or light or heater that defines the term outlet. It's the branch circuit serving an electrical box where you have installed utilization equipment or installed a box for the intentional use of a light or fan or other or installed a connection means like a receptacle to utilize the energy supplied by the branch circuit conductors.

The fact that I could convert the switch box to an outlet box is irrelevant. Until I do that afci is not required.

So Andy's switch in the bedroom has two things that keep it from needing afci it isn't an installed outlet and it isn't on a branch circuit that serves an outlet in a bedroom.

Summary

A switch on a branch circuit inherently becomes afci protected if it controls a light or similar energy consuming unit in a bedroom because the switch controls an outlet point for energy consuming unit(s). That outlet point must land in the bedroom for afci to be required to protect the branch circuit ( circuit breaker type) or the outlet (point of use type).
A device... switch or receptacle... does not define the point on the branch circuit as being an outlet, neither utilizes the electrical energy supplied by the branch circuit conductors. An electrical box in itself also does not mean that because I have access to the branch circuit conductors it is an outlet box. What defines the point of utilization (outlet) is whether or not the electrical box is installed to provide for the connection in that box of utilization equipment.

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Last edited by Stubbie; 11-12-2007 at 12:50 PM. Reason: spelling corrections
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Old 11-12-2007, 01:55 AM   #26
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BTW the new combination afci will trip at the same levels as the gfci around 5 ma and will detect series arcs. Two problems IMO that needed to be solved before CMP-2 would require afci in the rooms as listed in NEC 2008 code.

Qoute from a Mike Holt News letter

Why combination devices?
Standard branch/feeder AFCI devices operate when the arc exceeds 75A peak. But combination AFCI protection devices detect arcs as low as 5A peak. This dramatic difference in detection enhances safety performance. Combination devices are also intended to protect the premises wiring as well as the cord connecting the appliance. These devices also “see” arc faults for both series arcs and parallel arcs, whereas branch/feeder type AFCIs only respond to parallel arcs. See UL 1699, Standard for Arc-Fault Circuit Interrupters (www.UL.com) for information on differences between the two types.


I would also point out that the electricians and engineers over on Mike Holt that ran a thread containing over 780 posts on this switch issue have a history of taking simple concepts and turning them into huge hidden conspiracies tactfully thought out by the code writers to confuse the electrical industry. Most of those guys know the intent of the code but it is more interesting to them to search the outer reaches of the NEC to improve the level of boredom that has descended upon them. They are some of the best you will ever see at understanding the code but to take a switch and argue over that many posts whether or not you can call it an outlet for the use of utilization equipment is quite frankly comical IMHO. I especially like the argument in that thread that a switches internal contacts were a point to take current from the branch circuit conductors and therefore the switch is an outlet. Also the switch contacts weren't a part of the premise wiring so it had to be an outlet...jeeeeez some of those guys need to get a life.
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Last edited by Stubbie; 11-13-2007 at 01:03 AM.
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Old 11-13-2007, 07:58 AM   #27
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Now I remember why I moved from the Atlanta area.... I'll toss my vote for the need of the AFCI.
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Old 11-13-2007, 04:16 PM   #28
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Stubbie, Did you see that you qoute 5mA, but Mike Holt quotes 5A. Which is it??? That's a big old difference. Death is certain at 5A. chances are you are ok at 5mA.

Edit to add: of course the AFCI is for equipment and not personnel, so the difference between 70A and 5A is an improvement. Of course the difference between 5mA and 5A is huge.

Edit to add: I'm seeing GFP ratings of around 40mA for the new AFCI's. Cpuld be wrong though...hard to find solid info. Links?

Last edited by Andy in ATL; 11-13-2007 at 06:01 PM. Reason: clarification. Stubbie is my pal.
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Old 11-14-2007, 09:14 PM   #29
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A switch is not an outlet...for all the reasons Stubbie posted. With one Exception:

The city (or county, or parrish ) inspector says it is... and if it is a battle you choose not to fight.

You DIYers would truly be amazed at SOME (not all) of the inspectors your tax dollars pay for.

What the old adage? Those who can't, inspect.
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Old 11-14-2007, 10:24 PM   #30
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Quote:
Originally Posted by Andy in ATL View Post
You DIYers would truly be amazed at SOME (not all) of the inspectors your tax dollars pay for.
I am a DIYer and I am amazed at the lack of inspectors and the poor quality of inspections in my area. I have been waiting 3 weeks for an electrical inspection on my project. I can't install insulation and sheetrock until the work is approved by a city inspector. The work was done by a licensed electrician. I am also waiting on a plumbing inspection.

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