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  1. #1
    Forum Member firenresq77's Avatar
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    Default Nextel and GFI's

    I saw the other cell phone thread and it reminded me of this

    We had a class last week put on by one of our IBEW Locals and were told that they have found some incidents involving Nextel phones and GFIs. Apparently some of the electricians have gone to jobs and found GFI outlets that had caught fire and/or shorted out. All of these incidents happened when a Nextel phone was sitting on the kitchen counter and a call came in to the phone.

    When I had my service through Nextel, I noticed I could usually tell when I was about to get a phone call because I could hear would could be described as a "clicking" or "chattering" noise in electronic items nearby. This could be a car stereo, computer, scanner, portable/mobile radio, TV, whatever. After some of the Local's unofficial investigations and testing, they have found the same thing happens with GFIs. This has happened with different brands of GFIs. They report that the Nextel causes the GFI to "chatter" when a call comes in, and basically causes a rapid opening/closing of the circuit, which causes the GFI to overheat and cause a fire. They tried to test with other phones, but only found the problem with Nextel. Apparently the have had similar occurences with arc fault breakers.

    They have reportedly tried to address the issue (not sure with whom) but have gotten nowhere with it. They say nobody wants to do anythng unless there has been a high dollar loss.

    I'm not saying that anyone is embellishing anything, but had never heard any of this before and wasn't sure if any of you who are involved in Investigations had seen or heard of any of this before.
    The comments made by me are my opinions only. They DO NOT reflect the opinions of my employer(s). If you have an issue with something I may say, take it up with me, either by posting in the forums, emailing me through my profile, or PMing me through my profile.
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  2. #2
    Forum Member nmfire's Avatar
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    Default

    I just tried it with my hybrid and it didn't do anything. I'll try it with a regular nextel tomorrow.
    Even the burger-flippers at McDonald's probably have some McWackers.

  3. #3
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    Default Static Electricity Maybe?

    I am not a fire investigator at all. However I spent 6 years working in the wireless industry. This sounds to me like somehow the phone is creating entirely way to much static electricity. I would be interested to know what model phones they were by nextel It could be defective parts in certain models causing it. if you say regular cell phones do not cause this then the only other thing that could cause it is the two way radio portion of the nextel phone. Which lead me to wonder if other service providers two ways could cause it as well. Such as Verizons Push to talk. (they essentially are identical only different service providers.) When I left the wireless industry the only ones making direct connect phones were Motorola. I also would look into is were the phones in any way altered by the owner outside of normal manufacture guidelines and did they have some sort of signal boost device on them. That could create the problem. There have been reported cases were static electricity from phones have caused car fires when using them while fueling up at the pump. This could be a relative similar thing.

  4. #4
    Forum Member nmfire's Avatar
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    Ok most of that is totally wrong. Cell phones do not create, generate, or transmit "static electricity". Gas pump fires from static electricity discharges are from the person who already has a charge from sitting in the car, not from the phone they are using. The effects that a TDMA or GSM type phone have on nearby electronic devices has NOTHING to do with static electricity. It is plain and simple RF noise from the phone getting into unshielded components of the nearby electronic device. This happens with nearby radios, computer speakers, consoles, microphones, etc etc. It is perfectly conceivable that this kind of RF noise could mess with the electronics of a modern GFCI outlet.

    Nextel iDEN is nothing at all the same as Verizon's PTT service or any other PTT service. They are completely different animals that function in completely different manners using completely different protocols on completely different radios. CDMA does not create that pulsing RF noise and operates nothing like TDMA or GSM.
    Even the burger-flippers at McDonald's probably have some McWackers.

  5. #5
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    Default

    Quote Originally Posted by nmfire View Post
    Ok most of that is totally wrong. Cell phones do not create, generate, or transmit "static electricity". Gas pump fires from static electricity discharges are from the person who already has a charge from sitting in the car, not from the phone they are using. The effects that a TDMA or GSM type phone have on nearby electronic devices has NOTHING to do with static electricity. It is plain and simple RF noise from the phone getting into unshielded components of the nearby electronic device. This happens with nearby radios, computer speakers, consoles, microphones, etc etc. It is perfectly conceivable that this kind of RF noise could mess with the electronics of a modern GFCI outlet.
    Exactly right.

    A phone might be able to cause a GFI to trip, but certainly not catch on fire.

    Oh, and those videos of cell phones popping pop corn or anything similar to that are fake.

  6. #6
    Forum Member nmfire's Avatar
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    Actually the fire is stated to be a result of the GFCI's contacts rapidly opening and closing creating arcs and therefore enough heat to ignite the plastic around it. The RF from the phone gets in the electronics causing it to malfunction and chatter the contacts that normally just open and close.

    This makes perfect logical sense, however a GFCI outlet's high voltage contacts are not even designed in such a way to allow this to happen. Resetting a GFCI is a mechanical action that requires physical force to re-latch the contacts on the trip coil. It can not be "electronically reset" therefore it could not possibly chatter as described.

    If it caught on fire, it probably had nothing to do with the phone. Some idiot probably bamboozled the wiring and rammed 240 down its throat or something.
    Even the burger-flippers at McDonald's probably have some McWackers.

  7. #7
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    I went back and did a little research and see that I was wrong. They no longer think cell phones cause the gas pump fires. When I left the industry they were still putting out warnings about using them around gas pumps. That has changed since I left the industry. We are always advised to tell folks that phones due cause small amounts of static electricity but the possibility is very very rare to cause a spark. As of ptt and nextels Iden they in the end achieve the same thing as does cdma and tdma they do do it differently however I should of alluded to that. I did ask a friend who still works in the industry about the RF noise he said it Had to do with tdma phones using the time slot sharing technique use higher RF power. He said it was due to certain phones poor part placement as well.

  8. #8
    MembersZone Subscriber Halligan84's Avatar
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    Default

    I always get that "pre alert" if the Nextel is in a cup holder in my truck or laying near the computer.

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    Default

    Disclaimer - I'm not a firefighter - I just browse these forums out of general interest every once in a while. But I am an electrical engineer, so here are my two cents:

    I'm sure everyone already knows, but the Consumer Product Safety Commission (www.cpsc.gov) is the place to report anything burning up that shouldn't be. You may file a report at this link:

    http://www.cpsc.gov/talk.html

    You might encourage the electricians who have found these burned up GFCIs to file reports. It might also help a lot if they can hang on to the burned up units. It sounds like you have a good relationship with them. If they get no response then perhaps you could pool your efforts and find a forensic engineer to tear into some of these burned units.

    There are many ways to implement GFCI circuitry. But I would suggest that rather than focusing on Nextel exclusively the focus might be inadequate RF suppression in these models of GFCIs. Check out the GFCI recall information on cpsc.

    -A

  10. #10
    CFEI / CFII cubbie's Avatar
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    I think that it is possible to get these pre-alerts as they have been described. When a phone call is made to your phone the system pings your phone to locate it prior to putting the phone call through.
    I don't see how a low wattage transmission from a cell phone can start a fire in a GFI outlet. That is right up there with the myth of dropping a cigarette in gasoline will start a fire. Science just does not support it.

    When fire is cried and danger is neigh,
    "God and the firemen" is the people's cry;
    But when 'tis out and all things righted,
    God is forgotten and the firemen slighted.
    ~Author unknown, from The Fireman's Journal, 18 Oct 1879

  11. #11
    Forum Member nmfire's Avatar
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    Its not the RF from the phone creating a fire. It is the RF from the phone creating an electronic malfunction in the device. That malfunction causes the high voltage contacts to rapidly open and close. This causes a constant arc across the high voltage contacts which creates heat which creates fire.

    But as stated before, a GFCI doesn't work like that anyway
    Even the burger-flippers at McDonald's probably have some McWackers.

  12. #12
    Forum Member firenresq77's Avatar
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    As I said, I wasn't sure if this was possible or not. SUPPOSEDLY (and I emphasize that) they did their own tests using Nextel and various other phones and they achieved the same results.

    Maybe I will have to try to contact the gentleman and see if they can do their tests again and video tape it and email it to me.

    Thanks for everyone's input!
    The comments made by me are my opinions only. They DO NOT reflect the opinions of my employer(s). If you have an issue with something I may say, take it up with me, either by posting in the forums, emailing me through my profile, or PMing me through my profile.
    We are all adults so there is no need to act like a child........
    IACOJ

  13. #13
    Forum Member ziggy171's Avatar
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    Default other phone do it too

    Actually, I have had 3 phones, a Sony Ericson and 2 Razors and all of them have and currently still do the "pre-alert" sound when near speakers of some sort, or in the car, etc. For mine it's always ben about 4 or 5 short sounds then a long lasting sound then the phone rings. This also has happened with other's phone around too. Never any sparks or fire or anything to that nature.

  14. #14
    Forum Member nmfire's Avatar
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    Any phone that uses TDMA or GSM will make those annoying noises on nearby electronic devices. Nextel, AT&T, and I think T-Mobile are the main uses of those formats right now.
    Even the burger-flippers at McDonald's probably have some McWackers.

  15. #15
    CFEI / CFII cubbie's Avatar
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    The pre-alert is the phone synching up with the wireless network. This is very similar to what you hear when you listen to fax machines synching up before the fax is actually transmitted.
    You can hear the cell phone through electronic devices because the cell phone transitions from the sleep mode to active transmission while synching to the network. Most electronic devices are not designed to filter out the RF signal transmitted by the cell phone.
    I still can't accept that a properly working GFCI circuit would suffer a failure resulting in a fire caused by external RF transmissions from a cell phone.
    I am more concerned that you have identified that there are defective GFCI circuits on the market. I would like to know who the manufacture is. Are the GFCI circuits that have failed all been made by the same manufacture? If so then corrective action can be taken through the Consumer Product Safety Commission.
    Last edited by cubbie; 01-21-2009 at 11:12 AM.

    When fire is cried and danger is neigh,
    "God and the firemen" is the people's cry;
    But when 'tis out and all things righted,
    God is forgotten and the firemen slighted.
    ~Author unknown, from The Fireman's Journal, 18 Oct 1879

  16. #16
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    Default It trips on multiple manufactures

    I had a breakfast bar installed in my kitchen and the GFI outlet which is right under the counter of the breakfast will trip every time a cellular call comes in or a text message. When using the Nextel 2way feature it does not trip the GFI. The phone must be within a few inches of the receptical to trip the GFI. We changed out the receptical with another one of the same model, same result. We then tried a different model and still the same result.

  17. #17
    Forum Member nmfire's Avatar
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    Holy old post. But anyway, yet another reason i don't use nextel anymore. Everything around me is so quiet and works properly now.
    Even the burger-flippers at McDonald's probably have some McWackers.

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