Portable radio tripping GFCI

Status
Not open for further replies.
102 Inspector said:
I am certainly suprised with all the responces that I have received regarding this issue. Sounds like this is not the only one out there that might be doing this. Our radios work at the 800 range and scan multiple ranges and channels. 16 channels each bank with 4 banks of channels. Motorola XTS 5000R to be exact. I am going to have him change out radios for a week and see if problem continues. I am also going out to his house today with my radio to see if same issue can be duplicated. Because my after work hobby is to serve as Assistant Fire Chief, the radio being the problem does have me concerned so thanks for pointing out those issues. I will try to update after trying some of these suggestions.
Click to expand...

I went to Motorola's site and checked out the radio. I did not see any mention of FCC Part 90 certification, although I would not think Motorola would skimp out on that.

I also noticed the radios had a feature that enabled emergency communication without pushing the PTT button. Perhaps the radio is transmitting in emergency mode somehow??

Are you sure the radio is not a counterfeit? Motorola has warned their customers that fake public service two way radios are now coming out of Nigeria.

Someone mentioned periodic tone bursts. I didn't see that on the specs, and we don't use them here. Our public service radios are all Motorola. Tone bursts only happen on un-key.

Let us know what you find out. My hobby is radio, with a particular interest in emergency communications. I have friends that are firefighters and work on radios and if there is a Motorola issue, I know they would like to hear of it.

ON EDIT, maybe OT: Are your radios compliant with the new narrow band standard that went into effect in January? I see that the nomenclature for the radios indicate some may not be set for the new standard.
 
Last edited:
weressl said:
There were also bold signs on some of our control rooms "no portable radios allowed" and they would have a desk station with a remote antenna outside of the room, but the operators were not allowed to bring their portables into the area. We were looking for the origin or empirical evidence form the base of such restriction, but I've never seen any produced. Nowadays I see operators sitting at the board with the handhelds in hand.
Click to expand...
When I worked in the oil patch, many moons ago, there were incidents where workers were killed when CB radios prematurely set off downhole casing perforators when someone on site pushed their talk button while the tool was still up on the drill floor. These tools were basically multibarrel 50 cal. guns with armor piercing rounds aimed radially that were lowered down the drillpipe and triggered by radio when they got to the desired depth. If one went off above ground it really made a mess of things. Whenever a casing perforation was to be done, the crew set out signs a quarter mile or so out from the site saying "DANGER!! TURN OFF ALL CB RADIOS!!" and everyone not essential to the operation at hand made themselves scarce.
 
Last edited:
ggunn said:
When I worked in the oil patch, many moons ago, there were incidents where workers were killed when CB radios prematurely set off downhole casing perforators when someone on site pushed their talk button while the tool was still up on the drill floor. These tools were basically multibarrel 50 cal. guns with armor piercing rounds aimed radially that were lowered down the drillpipe and triggered by radio when they got to the desired depth. If one went off above ground it really made a mess of things. Whenever a casing perforation was to be done, the crew set out signs a quarter mile or so out from the site saying "DANGER!! TURN OFF ALL CB RADIOS!!" and everyone not essential to the operation at hand made themselves scarce.
Click to expand...

We tested RFI on telemetry devices at a hospital about 10 years ago. The rules were (back then) no cell phones. But, we saw EMT's and Firefighters carrying radios all the time.

None of the cell phones affected the machines at all, but when a transmission was made on a 2m frequency from a 5w hand held, some of the monitors, even several rooms away, would 'flat line'. As soon as the radio was not keyed, back to normal. The 'flat line' did not set off an alarm, so we were fairly certain just the monitor, not the cardiac machine, was affected. I would assume no one knew this because of the design of the hospital, public service radios wouldn't work inside so no one used them.

It's been a while since I have seen a 'no cell phone' sign at a hospital.
 
When I first started out as a sparky eons ago we were using the 2 way radios in the 800MHz range and we found out that they caused GFCI to trip. Known this for years. Never knew why the GFCI was sensitive to it though!:?
 
K8MHZ said:
I went to Motorola's site and checked out the radio. I did not see any mention of FCC Part 90 certification, although I would not think Motorola would skimp out on that.

I also noticed the radios had a feature that enabled emergency communication without pushing the PTT button. Perhaps the radio is transmitting in emergency mode somehow??

Are you sure the radio is not a counterfeit? Motorola has warned their customers that fake public service two way radios are now coming out of Nigeria.

Someone mentioned periodic tone bursts. I didn't see that on the specs, and we don't use them here. Our public service radios are all Motorola. Tone bursts only happen on un-key.

Let us know what you find out. My hobby is radio, with a particular interest in emergency communications. I have friends that are firefighters and work on radios and if there is a Motorola issue, I know they would like to hear of it.

ON EDIT, maybe OT: Are your radios compliant with the new narrow band standard that went into effect in January? I see that the nomenclature for the radios indicate some may not be set for the new standard.
Click to expand...
I have a few generators that if I key my Motorola 800Mh VIPER hand held close to the generator it will trip the gfci recptical in the generator.
 
We once hand a POS system in a resturant that would spike everyday around the same time and just mess it all up. We checked our stuff and the POS guys checked their stuff and we still couldn't figure it out. One day we were all there, and they had a scope hooked to it and we just all sat around watching it. Finally one of the POS guys says that he's going out to his car and smoke. About two minutes later the scope spikes and he comes running in and asks if it had. Yeah how did you know? He said he sat in his car turned on his CB and someone (probably on the freeway right next to us) keyed their mike and darn near blew out his windows. Guess he had a booster on his, and it turned out that the guy radioed his wife every night about the same time and let her know he was on his way home. Ended up we had to pull out all the cable and run shielded.
 
K8MHZ said:
It's been a while since I have seen a 'no cell phone' sign at a hospital.
Click to expand...
I have heard of one hospital doing away with their pagers and using only cell phones even in the ORs, yet their visting areas still say 'no cell phones allowed'.

Have we found an un-intended consequence of 800MHz radios?
 
What is being done is that you are exceeding the design limits of the GFCI - against radiated Immunity.
Any Electronic device can be made to operate abnormally when subjected to a high enough level of EMI.
That is why the military and space programs test their equipment to a much higher level than what consumer equipment may be subjected to.

EMI can induce high frequency currents directly into various parts of a circuit that may completely bypass the normal sensing mechanism of a device, and cause it to malfunction.

Electronic devices such are often tested to a certain level of EMI that they will tolerate. If that level is exceeded the device will likely malfunction. A quality manufacturer may elect to test to a higher level to make their equipment more robust. Others may test to the minimum ( or elect to not test at all if not required to meet any Immunity standards). Europe does a better job at requiring this type of testing than the US does:
http://www.techintl.com/emcinusa.cfm

I used to be involved in EMC testing of equipment that was sold overseas and was required to be CE marked ( and thus Immunity tested). We tested to a level of 10V/meter even though at the time we were only required to meet the 3V/meter requirement.
When testing the frequency is continuously varied over a wide range and the field strength is monitored.

When using a hand held transmitter it is very possible to exceed a devices Immunity level at a close range.
Cell phones transmit at a very low level and are not nearly as likely to interfere with equipment as hand held radios with a higher power output.

We often encountered maintenance people upsetting equipment when using their radios in "too close" of proximity to various equipment.
 
ELA said:
What is being done is that you are exceeding the design limits of the GFCI - against radiated Immunity.
Any Electronic device can be made to operate abnormally when subjected to a high enough level of EMI.
That is why the military and space programs test their equipment to a much higher level than what consumer equipment may be subjected to.

EMI can induce high frequency currents directly into various parts of a circuit that may completely bypass the normal sensing mechanism of a device, and cause it to malfunction.

Electronic devices such are often tested to a certain level of EMI that they will tolerate. If that level is exceeded the device will likely malfunction. A quality manufacturer may elect to test to a higher level to make their equipment more robust. Others may test to the minimum ( or elect to not test at all if not required to meet any Immunity standards). Europe does a better job at requiring this type of testing than the US does:
http://www.techintl.com/emcinusa.cfm

I used to be involved in EMC testing of equipment that was sold overseas and was required to be CE marked ( and thus Immunity tested). We tested to a level of 10V/meter even though at the time we were only required to meet the 3V/meter requirement.
When testing the frequency is continuously varied over a wide range and the field strength is monitored.

When using a hand held transmitter it is very possible to exceed a devices Immunity level at a close range.
Cell phones transmit at a very low level and are not nearly as likely to interfere with equipment as hand held radios with a higher power output.

We often encountered maintenance people upsetting equipment when using their radios in "too close" of proximity to various equipment.
Click to expand...

Indeed, bullet-proof always specifies the type of bullet and velocity it will withstand.
 
ELA said:
...
Cell phones transmit at a very low level and are not nearly as likely to interfere with equipment as hand held radios with a higher power output.
...
Click to expand...

Except with a Fluke 87-V more than a year or so old. Lay your cellphone down next to one and talk to someone on speakerphone or get a call with your cellphone laying next to the multimeter, your Fluke will most likely get bricked. Needless to say, Fluke have now revised the internal shielding ;)

P.S. Please don't try this if you own an 87-V... it really doesn't take long to brick it.
 
PetrosA said:
Except with a Fluke 87-V more than a year or so old. Lay your cellphone down next to one and talk to someone on speakerphone or get a call with your cellphone laying next to the multimeter, your Fluke will most likely get bricked. Needless to say, Fluke have now revised the internal shielding ;)

P.S. Please don't try this if you own an 87-V... it really doesn't take long to brick it.
Click to expand...

Did you end up trying this for yourself or are your comments based on something you read once?

http://www.eevblog.com/forum/testgear/fluke-87v-screen-goes-crazy-with-wifi-cell-phone-signals/15/ ->8 posts down
 
Just completed random testing around fire station with 2 different radios. When located within 2 feet, the GFCI with plastic cover plates tripped while the metal covers did not. Held radio 2 feet from and keyed up radio to transmit and the receptacle made a sizzle noise, but never tripped. Tested test button and then with additional testing equipment and device reacted properly. Firefighter will be changing out to metal cover plates at his house and doing some more testing.
 
ELA said:
Did you end up trying this for yourself or are your comments based on something you read once?

http://www.eevblog.com/forum/testgear/fluke-87v-screen-goes-crazy-with-wifi-cell-phone-signals/15/ ->8 posts down
Click to expand...

I did not test one personally, but now I've read it twice ;) I know the OP of that thread personally, and I know the owner of the website by reputation and private correspondence. I know he did follow-up testing which confirmed the issue and that Fluke did make changes to the shielding of the 87-V when the latest version was released. And no, my Agilents are not affected.
 
Portable Radio Tripping GFCI

Portable Radio Tripping GFCI

The 800 MHz radio systems are UHF and not VHF systems. Most of these systems are highly automated trunking systems that function much like our cellular networks. The system needs to know where each radio is located so that it's traffic can be routed to the closest tower.

The statement that "The radio only occasionaly trips the GFCI" would seem to confirm this. These trunking systems will check each radio on the system periodically to determine its status and location. This can occur without operator input and generally without their knowledge.

As most public safety agencies select and use quality equipment I doubt that a defect is responsible here. The best solution would be to find a different location to set radio while it is in standby use.
 
Status
Not open for further replies.
Top