Arc faults- Bedrooms and Smoke Detectors

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Re: Arc faults- Bedrooms and Smoke Detectors

There are smoke detectors on the market that have a secondary signaling system.Did a home a few years ago and the alarm company wanted to be notifed when they signaled.Not sure which brand it was but it did have a secondary sinaling system.I could do research if anyone needs to know let me kmow ;)
 
Re: Arc faults- Bedrooms and Smoke Detectors

Let me give you this scenario. Modern televisions operate with the power supply energized and the microprocessor running all of the time. This is so that the remote control can turn on the television. There have also been some computer motherboards and other consumer electronics that have had a rash of electrolytic capacitor failures.

One of the electrolytic capacitors in the television fails enough to start a small fire and trip the AFCI which also shuts down the SMOKE DETECTOR. The television burns for s few minutes and then the fire fizziles out. The toxic smoke from this little fire kills somebody's child or parents. Nothing happens to the rest of the house. The HVAC system sucks in and dilutes the fumes at such a rate that the other smoke detectors do not activate and nobody else is hurt.

Do you want a wrongful death lawsuit or go to jail for negligent manslaughter? I do not care if the smoke detector is connected to a central fire alarm panel or not.

You can always find a case where the smoke detector is needed for the same reasonj that the A$$ F^&*ing C$@% Injector is needed.

As far as I am concerned AFCIs are pure voodoo - there is NOT a way to determine the difference between an arc that is supposed to be there and one that is not supposed to be there. AFCIs are derived from a FAILED technology that was supposed to be able to detect downed utility power lines automatically. Yes, there was such a thing as an AFCI for use at electrical utility substations long before 120 volt AFCIs.

As long as the National Electrical Code people say that I have to use these for bedroom circuits I will put them in but the smoke detector IS NOT going on that circuit!
 
Re: Arc faults- Bedrooms and Smoke Detectors

How can you even say that ;) 2002 clearly changed that in which the wording was changed to outlet.... Go to 100 and it clearly says ANY POINT (SMOKE INCLUDED) THAT UTILIZES POWER.With that said a smoke must be afci protected :Don` t put them on an afci circuit and you are in total violation of a cut and clear NEC requirement.A good point has already been made that it is practiable to run the feed back yo the panel and make a joint in the panel for the smokes and a bedroom.We have had problems with tagging off a bed room circuit and feeding the smokes I have told our guys run it back to the panel ,make a joint on trim that way if there is a problem we can split them ion a panel and add a breaker ;) But to say that you will not put them on an afci circuit is wrong !!!!!!NEC requires it :eek:
 
Re: Arc faults- Bedrooms and Smoke Detectors

Originally posted by mc5w:
One of the electrolytic capacitors in the television fails enough to start a small fire and trip the AFCI which also shuts down the SMOKE DETECTOR. The television burns for s few minutes and then the fire fizziles out. The toxic smoke from this little fire kills somebody's child or parents. Nothing happens to the rest of the house. The HVAC system sucks in and dilutes the fumes at such a rate that the other smoke detectors do not activate and nobody else is hurt.
Click to expand...
The smokes that I (and I think most of us install) have a battery backup to continue operation during a power outage.

By NFPA 72, we have to interconnect the smokes so that if one detects smoke, they all alarm throughout the entire house. There is one in every bedroom, so unless you're passed out on the porch, you will hear it. See this thread for the requirements.

As long as the National Electrical Code people say that I have to use these for bedroom circuits I will put them in but the smoke detector IS NOT going on that circuit!
Click to expand...
Whether it is on the bedroom circuit or not, it is required to be AFCI protected. 210.12, coupled with the definition of an "outlet" make that clear.

Since the house wiring is left to us cheap numbnuts, I'd not trouble yourself too much over it.
 
Re: Arc faults- Bedrooms and Smoke Detectors

mc5w,
I do not see anything in NEC 760.21 through 760.28 that requires an alarm panel so line voltage smoke detectors without an alarm panel would still be a fire alarm circuit.
Click to expand...
Article 760 only applies to fire alarm systems.
760.1 Scope.
This article covers the installation of wiring and equipment of fire alarm systems including all circuits controlled and powered by the fire alarm system.
Click to expand...
Don
 
Re: Arc faults- Bedrooms and Smoke Detectors

As per NFPA 72 definitions, Smoke Detectors are part of a fire alarm system, with the sounding element not an integral part, usually it is a horn or bell. Whereas the Smoke Alarm has an integral sounding element and is generally not part of an alarm system. The line voltage stand alone or multiple interconnect units are called Smoke Alarms ;) .

That is why you will see the different terminology used in NFPA 72, 99 and 101, which used to confuse me to no end until I learned this.
 
Re: Arc faults- Bedrooms and Smoke Detectors

I will just have to give up on you guys. You do not see the greater hazard if somebody fails to change the backup battery. I know someone who put up with the periodic chirp for 2 years because he did not know what it was.

I will just have to aks my local inspector what he wants. As far as I am concerned a single smoke detector or multiple smoke detector ARE a fire alarm. Why else would we put it there?
 
Re: Arc faults- Bedrooms and Smoke Detectors

Originally posted by mc5w:
I will just have to give up on you guys. You do not see the greater hazard if somebody fails to change the backup battery.
Click to expand...
:cool:

Originally posted by mc5w:
As far as I am concerned a single smoke detector or multiple smoke detector ARE a fire alarm. Why else would we put it there?
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The interconnected 'smokes' we put in a typical house are not called smoke detectors by UL, they are called smoke alarms.

A smoke detector used for open area protection to UL and the NEC is a component of a fire alarm system and can not be used without other components.

The smoke alarms we install in a home are not a fire alarm system as far as UL or Article 760.


2004 UL White Book
Single- and Multiple-station Smoke Alarms
(UTGT)
USE
This category covers single- and multiple-station alarms intended to be
employed in ordinary indoor locations of residential occupancies as
defined in NFPA 101, ??Code for Safety to Life from Fire in Buildings and
Structures?? (1997 edition), section 4-1.6 group (d) one- and two-family
dwellings. These units are intended only for locations where normal ceiling
temperatures between 4.4?C (40?F) and 37.8?C (100?F) prevail.
This category also covers single- and multiple-station smoke alarms that
have been performance tested to a minimum 10-year extended battery life
under normal ambient conditions.
ALARM TYPES
Single Station ? Self-contained units that incorporate a smoke chamber,
an optional heat detector, and related electrical components to initiate an
audible alarm signal from the unit when abnormal smoke or heat (when a
supplementary heat detector is provided) actuates the unit. These devices
may be energized from a commercial power supply source by means of
permanent wiring in accordance with NFPA 70, ??National Electrical
Code,?? flexible supply cord, use of limited energy cable or equivalent wiring
connected to the output of a suitable Class 2 power supply, or by one
or more batteries.
Where a battery is employed as the main supply, its depletion below the
level at which an alarm signal would be obtained is indicated by a distinctive
audible trouble signal which persists for at least seven days.
Multiple Station ? Similar to single-station units but provided with
leads or terminals to permit the interconnection of single-station units so
that actuation of any one unit results in actuation of the audible alarms of
all units. The installation instructions (manual) indicate the maximum
number of units that can be interconnected.
Click to expand...
2004 UL White Book
Smoke-automatic Fire Detectors (UROX)
GENERAL
This category covers detecting combinations designed to detect smoke
particles. Smoke detectors may or may not be designed to be connected to
fire alarm system control units. See ??Applications?? section.
Click to expand...
When we look at the ??Applications?? section we find;

APPLICATIONS
Open Area Protection (OAP) ? Requires detector connection to a compatible
system control unit for operation.
Click to expand...
While Article 760 covers smoke detectors as defined by UL, 760 does not cover smoke alarms.

mc5w you must remember to separate how you like to do things from actual code requirements.

Bob

[ March 25, 2005, 05:07 AM: Message edited by: iwire ]
 
Re: Arc faults- Bedrooms and Smoke Detectors

For what it is worth, Indiana does not require AFCIs to protect anything but the circuits that feed the receptacle outlets. From the Indiana Electrical Code, "In Section 210.12(B), Dwelling unit bedrooms, delete "outlets" and insert "receptacle outlets "
 
Re: Arc faults- Bedrooms and Smoke Detectors

mc5w,
I will just have to give up on you guys. You do not see the greater hazard if somebody fails to change the backup battery.
Click to expand...
We are talking about what the code requires, not if you or I see the code requirement as a greater hazard. Apparently CMP 2 does not see this as a greater hazard as there were a number of proposals to exempt the bedroom smoke alarms from the AFCI rule, but they were all rejected.
Don
 
Re: Arc faults- Bedrooms and Smoke Detectors

One of the dumbest things that the NFPA ever did was to require that third wire for a laundry circuit. A couple of years later those dummies said that we would not only use a third wire but we would have to protect it with those always tripping GFCI gismos in bath rooms.

Now tell me, Have you ever heard of anything so stupid?

Yes!!!! Now those dummies want me to protect smoke alarms with those always tripping Arc Fault thing-a-muggier.

I think the reason they (NFPA) keeps doing things like this is so we (electricians) will have something to fuss about. We all know that there are houses out there that have Knob and Tube wiring and they are doing just fine. I have even found a few through my 30 plus years that had an Abe Lincoln behind a fuse or two that was working just fine.

Will there ever be an end to this stupidity?

Yes I am being facetious.

[ March 25, 2005, 01:09 PM: Message edited by: jwelectric ]
 
Re: Arc faults- Bedrooms and Smoke Detectors

The NEC reference to article 760 applies to "systems" not to single station smoke detectors.

I know that local inspectors and various AHJ's are all over the map on this issue, but if you review the code panel's responses in both the 2002 and 2005 code cycle to specific ROP's and ROC's, they are very clear that the "outlets" required to be arc fault protected include the smoke detector outle.

It is my humble opinion that folks that ignore the code panels responses and the existing text of the NEC are asking for trouble.
 
Re: Arc faults- Bedrooms and Smoke Detectors

Although 760 is indeed for "systems", NFPA 72 11.6.3 (5) does prohibit GFCI protection of smoke alarm circuits unless the GFCI protection serves all electrical circuits within the dwelling unit.

There is no such prohibition of AFCI's and smoke alarms.

Roger
 
Re: Arc faults- Bedrooms and Smoke Detectors

Apparently CMP 2 does not see this as a greater hazard as there were a number of proposals to exempt the bedroom smoke alarms from the AFCI rule, but they were all rejected.
Don
Click to expand...
I wouldn't jump to any conclusions as to whether something's a good idea or not based on the actions of CMP 2. I've read some of the stuff they've written and I can't help but wonder if clear thinking is one of their strong points.

I'm a big GFI fan and I always get the "where's the body count?" treatment and rightly so, but has the same test been applied to AFI's on smoke alarms? Are smoke alarms really burning houses down?

Something just isn't right about CMP 2 and the AFCI's. Are AFCI's even reducing electrical fires?
 
Re: Arc faults- Bedrooms and Smoke Detectors

Pierre, I wonder the same thing. There is no specific statement of GFP being allowed at any level, people or equipment.

This will be addressed I'm sure.

a similar situation was NFPA 99 chapter 3 and NFPA 70 article 517 conflicting over automatic doors and what branch was to serve them in the 96 code cycle.

NFPA 99 was requiring these doors to be fed from the Life Safety branch, yet NFPA 70 was still mandating they be fed from Critical or Equipment branches

Roger

[ March 25, 2005, 06:22 PM: Message edited by: roger ]
 
Re: Arc faults- Bedrooms and Smoke Detectors

From now on I am going to tell people to get a genuine fire alarm system. This gets rid of the 9 volt battery problem and the bedroom AFCI problem. The 24 volt rechargeable battery in a genuine fire alarm is superior and a lot easier to replace.

I have an instance of a retail business that proves that the low battery chirp from 120 volt residential smoke detectors is at least 99% INEFFECTIVE at getting people's attention. It took 2 years of nagging on my part to get three 9 volt batteries changed. One maintenance headache was that the only ladder for the job took 2 people to handle.

Now you are going to ask, why does this business have 3 residential smoke detectors wired together? Well, they are affordable and this occupancy type and size is not required to have a real fire alarm system. The cheap residential stuff is better than nothing.
 
Re: Arc faults- Bedrooms and Smoke Detectors

The ground fault protection that is built into an AFCI is for equipment protection and I believe that the trip level is 50 milliamperes. It is NOT for people protection. If you also want GFCI for people that has to be added downstream.

The ground fault protection is one of the sources of nuisance tripping. These have several sources:

1. Accidental neutral regrounding. One quick test is to temporarily swap hot and neutral. SquareD is now recommending a 500 volt or 1000 volt megger test just like with mobile homes.

2. Haywiring. There are still some electricians around here who will wire stairway lights by tapping a hot wire on the first floor, go through the 3-ways and 4-ways with 14/2 or 12/2, and then use a neutral on the second floor to run the light. Like they never heard of 14/3 or 12/3.

3. There is a small water problem somewhere and the GFCI or AFCI is picking it up. Catching water damage early actually saves money.

4. When loads turn off circuit inductance tends to force a phantom ground fault to flow through insulation capacitance to ground. If about 0.2% of the starting current of a 120 volt 1/2 HP split phase motor diverts into the motor frame when the starting switch opens, an AFCI will read that as a ground fault and trip. For GFCI for people the problem is even worse. Some of my buddies have had to take a bathroom light off a GFCI because when the light switch is turned off the phantom ground fault trips the GFCI. Seems to only happen with magic circuit lengths.

5. People play with the test button on a GFCI outlet.

6. I suspect that some people actually plug themselves into a GFCI outlet just to see what happens. How we found out that grandmother could not let go of 120 volts was how we found out that rabbits think that 120 volts is delicious. We did unplug her before serious damage occured. She died of cance many years later.
 
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