AFCI Nuisance tripping

[jfincherok]

Thanks for the responses so far. Here's an update:

The electricians were out last wednesday and I had them take the tankless (gas) water heater off one of the branch circuits and put it on it's own dedicated non-AFCI circuit and they installed a whole house surge protector on the panel in an attempt to eliminate potential noise. The tripped AFCI breakers escalated immensely. They had 2-6 breakers tripping at a time. Yesterday, the homeowner claimed it happened 18 times for a total of 44 tripped breakers. They mentioned off-hand that it happens frequently when they use the hot water. The new circuit for the water heater was at the top of the panel so the electrician moved it to the bottom of the panel and voila! Only one breaker is tripping and seemingly only when the hot water is engaged. Time will tell if this was in fact the issue. This makes no sense to me because everything is connected on the buss and it shouldn't matter where it is on the panel, correct? I can understand problems happening on one leg or phase over the other, but why would it matter where it was attached on the bus? Could be the inductive carryover mentioned by someone else above?

Also, the CH rep claims one breaker can't trip the others. Makes sense to me but it's what seems to be happening. The electrician was on the phone to the water heater engineers and traced it down to a malfunctioning component on the water heater that will be sent to us and installed friday, I hope. Also, the CH rep is sending all new breakers that have some kind of filter or surge protection built in to make them a little less sensitive to whatever is going on in the panel. If this works, I'll post the results and hopefully save someone else a lot of trouble who reads this.

We've ordered the diagnostic tool from Siemens and it should be in tomorrow. I suspect it would have helped us pinoint the water heater as the problem. If so, it would have saved us a lot of money and grief over the $350 price tag for it. We'll go ahead and test everything else with the tool to make sure nothing else is going on. More to come.......

 

[cowboyjwc]

Depends on what it is. Before any electrician takes one out they should megger and check connections. Look at equipment too. But, defects aside tripping could also be from overloads. Houses that once had 1 circuit for every room now have 4 for everything outside of the required appliance circuits in an effort to off set AFCI costs. I see new 2000 sqft houses with only 4 15 amp or 3 20amp 120 volt circuits for everything general use + lights. CMP should have increased the va per foot requirements for AFCIs but didn't. AFCIs have back fired enormously.

Well yes it could be an overload, but then the breaker is still doing it's job. I have not looked at the problem as it's not in my jurisdiction, but I will try to be kept in the loop as to what's going on. The original contractor doesn't seem to be overly competent, but he should get a chance to find out what's going on before they have to bring in someone else.

 

[mbrooke]

Thanks for the responses so far. Here's an update:

The electricians were out last wednesday and I had them take the tankless (gas) water heater off one of the branch circuits and put it on it's own dedicated non-AFCI circuit and they installed a whole house surge protector on the panel in an attempt to eliminate potential noise. The tripped AFCI breakers escalated immensely. They had 2-6 breakers tripping at a time. Yesterday, the homeowner claimed it happened 18 times for a total of 44 tripped breakers. They mentioned off-hand that it happens frequently when they use the hot water. The new circuit for the water heater was at the top of the panel so the electrician moved it to the bottom of the panel and voila! Only one breaker is tripping and seemingly only when the hot water is engaged. Time will tell if this was in fact the issue. This makes no sense to me because everything is connected on the buss and it shouldn't matter where it is on the panel, correct? I can understand problems happening on one leg or phase over the other, but why would it matter where it was attached on the bus? Could be the inductive carryover mentioned by someone else above?

Also, the CH rep claims one breaker can't trip the others. Makes sense to me but it's what seems to be happening. The electrician was on the phone to the water heater engineers and traced it down to a malfunctioning component on the water heater that will be sent to us and installed friday, I hope. Also, the CH rep is sending all new breakers that have some kind of filter or surge protection built in to make them a little less sensitive to whatever is going on in the panel. If this works, I'll post the results and hopefully save someone else a lot of trouble who reads this.

We've ordered the diagnostic tool from Siemens and it should be in tomorrow. I suspect it would have helped us pinoint the water heater as the problem. If so, it would have saved us a lot of money and grief over the $350 price tag for it. We'll go ahead and test everything else with the tool to make sure nothing else is going on. More to come.......

AFCIs cant distinguish noise, harmonics, transients, radio frequency, current ripples and arcs anywhere close to satisfactory. I see it all the time. If I was in that position I would've taken all the AFCIs and not bothered wasting so much money and effort. The CH rep is covering up the down falls. AFCIs can be very sensitive to induced magnetic fields. Its possible the water heaters normal non sinusoidal current draw is causing its breaker to induce high frequency interference into the neighboring breakers. If the water heater is actually malfunctioning who knows. Many UL listed appliances will trip them.

Well yes it could be an overload, but then the breaker is still doing it's job. I have not looked at the problem as it's not in my jurisdiction, but I will try to be kept in the loop as to what's going on. The original contractor doesn't seem to be overly competent, but he should get a chance to find out what's going on before they have to bring in someone else.

AFCIs do a nice job with overloads, bolted faults and 30ma protection for those that have then but its the arc feature that is causing a great deal of problems as well.



BTW, Im curious if you can find out how many general use circuits are in the house vs square footage. Just one of those things AFCIs peaked my curiosity in.

 

[don_resqcapt19]

We were involved last year with a similar problem with AFCIs tripping for no apparent reason on new construction at a college. This involved some of the dorm rooms. The manufacturer of the panels and breakers was CH.

First thing I would tell you to do is go to the manufacturers website and download the technical information on the breakers. They also have a very good troubleshooting document regarding the AFCI breakers. Then you need to contact their AFCI Application Engineers. They will help you in troubleshooting the problems.

We purchased an Amprobe INSP-3 tester to help in the troubleshooting of our AFCI problems. We followed the CH troubleshooting guide and documented everything. After working with the CH application engineer, and sending them all of our test data, it was determined that they would send us at no charge, all of the newest generation AFCI breakers that we needed.

We replaced all of the AFCI breakers and sent the other breakers to CH for evaluation. We have not had a call back at all. All breakers functioning correctly!

All of the data that the various manufacturers obtain from us in regards to AFCI breakers, not only helps them in improving their product, but helps all of us in the long run. Good luck!:thumbsup:

Did you sent them an invoice for all of the troubleshooting labor? Why should the contractor have to eat that when it appears that the original AFCIs were at fault? These devices are just not ready for the real world, but it was a great move getting them into the code so that the general public and the electrical contractors had to pay for all of the beta testing of an incompletely designed device.

 

[mopowr steve]

I think it is a good idea to learn what causes these problems and have a better understanding of AFCI's in general, but still don't think it is right to force consumers to spend the money on all that testing and essentially find there is nothing wrong with any of their premises wiring or connected equipment but rather a flaw in the design of the AFCI that doesn't discriminate the condition from a true fault. The whole AFCI thing was a good idea to pursue, but they forced it on consumers before it was even close to perfected and are making the consumer become part of the testing lab.

I'm with you on that!
Cost me a lot of "chalk it up as experience" time.
Heck wouldn't it be ok to install military barracks or housing with new products to test them out and give them a chance to find faults before they make it to mainstream?

 

[electric_cal]

Did you sent them an invoice for all of the troubleshooting labor? Why should the contractor have to eat that when it appears that the original AFCIs were at fault? These devices are just not ready for the real world, but it was a great move getting them into the code so that the general public and the electrical contractors had to pay for all of the beta testing of an incompletely designed device.

I agree with you completely Don, but what choice did we have? The damn things are in the code and we are stuck with them. :rant:

Heck, you know the answer to that. If I had sent them an invoice, we would still be fighting about it! :happysad:

It's just another case where manufacturers of electrical devices and material have placed them into the field and then they have their unpaid R & D groups, us, complete the field trials and find all the bugs! We have all been there, and i'm sure we will be there again.

 

[cowboyjwc]

BTW, Im curious if you can find out how many general use circuits are in the house vs square footage. Just one of those things AFCIs peaked my curiosity in.

I'll see what I can find out, I was really just being consulted on the job and don't really have any hand's on with it.

 

[kwired]

Depends on what it is. Before any electrician takes one out they should megger and check connections. Look at equipment too. But, defects aside tripping could also be from overloads. Houses that once had 1 circuit for every room now have 4 for everything outside of the required appliance circuits in an effort to off set AFCI costs. I see new 2000 sqft houses with only 4 15 amp or 3 20amp 120 volt circuits for everything general use + lights. CMP should have increased the va per foot requirements for AFCIs but didn't. AFCIs have back fired enormously.

I see no good reason to increase VA per foot requirements. These devices are not tripping on overload, they are tripping because they can't tell the difference between an acceptable and a non acceptable current signature in certain instances, if anything the CMP should be putting more pressure on the manufacturers to get a better product if they wish to have them remain in the code.

I'm with you on that!
Cost me a lot of "chalk it up as experience" time.
Heck wouldn't it be ok to install military barracks or housing with new products to test them out and give them a chance to find faults before they make it to mainstream?

someone still has to pay for them an it is not going to be the AFCI manufacturers

 

[don_resqcapt19]

...
Heck, you know the answer to that. If I had sent them an invoice, we would still be fighting about it! :happysad:
...

A big company like that might not even respond to a case filed in small claims court...

 

[mbrooke]

I see no good reason to increase VA per foot requirements. These devices are not tripping on overload, they are tripping because they can't tell the difference between an acceptable and a non acceptable current signature in certain instances, if anything the CMP should be putting more pressure on the manufacturers to get a better product if they wish to have them remain in the code.

Trust me I know, its the arc fault logic that trips them. However, builders are cutting back as much as possible on wiring to off set the cost. Houses are theoretically less safe under AFCI codes then before. Im now seeing houses with only 3 general use circuits where the same builder before was much more courteous prior. I know, not NEC required, and not every builder was generous, but its having an impact in reality. Same with craigs list hackers winning bids over electricians since they dont have to upgrade to AFCIs on a panel change or circuit extension.

 

[kwired]

Trust me I know, its the arc fault logic that trips them. However, builders are cutting back as much as possible on wiring to off set the cost. Houses are theoretically less safe under AFCI codes then before. Im now seeing houses with only 3 general use circuits where the same builder before was much more courteous prior. I know, not NEC required, and not every builder was generous, but its having an impact in reality. Same with craigs list hackers winning bids over electricians since they dont have to upgrade to AFCIs on a panel change or circuit extension.

If you run necessary separate SABC, laundry, bath, or dedicated circuits for certain appliances, 3 - 20 amp circuits often can handle the entire remainder of the house, though many often install more circuits then that. If the AFCI is tripping on other then overload then the VA calculation is not the problem, the fact the AFCI can't properly discriminate between acceptable and non acceptable current signatures is the problem.

That said I do not disagree that because of the cost of AFCI's many installers are tempted to put more outlets on a circuit then they used to where AFCI protection is required. Copper isn't as cheap as it once was and is also a reason to consider changing wiring schemes a little to help cut cost.