Simultaneous tripping of AFCI receptacles

Reply

  #1  
Old 01-09-16, 11:07 PM
Member
Thread Starter
Join Date: Dec 2013
Location: USA
Posts: 8
Received 0 Votes on 0 Posts
Simultaneous tripping of AFCI receptacles

Hopefully this question isn't off topic. I'm new to the forum so apologies if so.

Here's the situation. Two sets of bedroom receptacles are newly wired (replacing the old k&t with work completed in the last 12 months by yours truly) using two 20 amp circuits (one for each bedroom). Both are AFCI protected using a receptacle type of protection device (15 amp receptacles). I did a TON of research in completing my whole house rewiring project (with a lot of help from this forum, incidentally), and believe the work I did to be quality work: followed code requirements, passed inspection, and didn't cut corners anywhere.

At night, we are running a space heater in each bedroom. Both AFCI devices are tripping at some point in the night, but not every night.

Tonight I was able to experiment a bit after they had both already tripped, and confirmed that BOTH of the space heaters seem to be causing the issue. In addition, each heater will, on its own, trip BOTH of the AFCI receptacles in these rooms despite not being in the same circuit. To be clear: this doesn't always happen, it only happens on some nights after they have both been going for a while.

Furthermore, if I take either heater to another room (also AFCI protected), they do not trip the device.

I am looking for advice as to what to do about this situation: how to determine what exactly might be causing it, and whether there is something I can do to fix it.
 
Sponsored Links
  #2  
Old 01-09-16, 11:14 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 53,522
Received 408 Votes on 384 Posts
Welcome to the forums.

You're using AFCI receptacles ?

Unfortunately there isn't much you can do. The thermostats in the heaters are either arcing on make (heat on) or arcing on break (heater off).

Are they new.... can they be returned ?
 
  #3  
Old 01-09-16, 11:29 PM
Member
Thread Starter
Join Date: Dec 2013
Location: USA
Posts: 8
Received 0 Votes on 0 Posts
They're fairly new, but not new enough they can be returned.

Is there no other possibility? Why would ONE heater be tripping two AFCI receptacles that aren't even on the same circuit? And how is it possible that BOTH the heaters only cause the fault on their own after the circuits have been in use for a while?
 
  #4  
Old 01-09-16, 11:59 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 53,522
Received 408 Votes on 384 Posts
If you want to make a test..... bring an AM radio near to the heaters..... even in the same room. Turn the heaters on and off and listen to the noise they create. That is an arc. That's what's tripping your AFCI devices.

A load on one circuit can trip a protection device on another circuit if the wires are run parallel to each other as the arc can be induced.
 
  #5  
Old 01-10-16, 12:28 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
Because of amp draw on high it is best to run heaters on dedicated circuits. I'd suggest you run a new circuit for each heater and do not use AFCI protection (two birds killed, one stone) or hard wire in a couple of small baseboard heaters. If your local code requires AFCI hard wired is probably your best option.
 
  #6  
Old 01-10-16, 07:16 AM
Member
Thread Starter
Join Date: Dec 2013
Location: USA
Posts: 8
Received 0 Votes on 0 Posts
I'm considering hardwired baseboard heaters on a 20A three wire 220 circuit. This would obviously solve the problem. I just wanted to make sure the problem really is in the space heaters and not a problem with the circuit.
 
  #7  
Old 01-10-16, 09:25 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,972
Received 59 Votes on 52 Posts
Furthermore, if I take either heater to another room (also AFCI protected), they do not trip the device.
This tells me that you might have some bad AFCIs. Are the devices (the ones that trip and the ones that do not) the same?
 
  #8  
Old 01-10-16, 05:39 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 10,092
Received 29 Votes on 23 Posts
th
Two sets of bedroom receptacles are newly wired (replacing the old k&t with work completed in the last 12 months by yours truly) using two 20 amp circuits (one for each bedroom). Both are AFCI protected using a receptacle type of protection device (15 amp receptacles).
You had mentioned at one point that these new circuits had been inspected and passed. If AFCI protection as required by the NEC is what you were wanting to accomplish, how are the branch circuit feeders from the panel to the AFCI receptacles being protected. The NEC requirement is for the entire circuit to be protected and not just the receptacles. Is this installation not intended to meet code, but just for added protection?
 
  #9  
Old 01-10-16, 06:28 PM
Member
Thread Starter
Join Date: Dec 2013
Location: USA
Posts: 8
Received 0 Votes on 0 Posts
Tolyn: they are the same type of AFCI, yeah.

Casual Joe: it is a requirement. I wouldn't have them otherwise (have heard about a lot of problems with nuisance tripping). I'm not a code monkey by any means but my understanding is that the protection requirement is for the outlets, not the circuit, and the AFCI is protecting the first outlet on each circuit. Could be wrong about that.

At any rate, the local official passed it so whatever, don't care.
 
  #10  
Old 01-10-16, 06:46 PM
Member
Thread Starter
Join Date: Dec 2013
Location: USA
Posts: 8
Received 0 Votes on 0 Posts
Casual Joe:


Following up on your question, this thread at the Mike Holt forum seems to say the receptacle type AFCI devices fulfill NEC requirements (as long as the home run isn't too long):

AFCI - GFCI ins 2014 NEC
 
  #11  
Old 01-11-16, 11:10 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 10,092
Received 29 Votes on 23 Posts
this thread at the Mike Holt forum seems to say the receptacle type AFCI devices fulfill NEC requirements (as long as the home run isn't too long):
I don't have a copy of the 2014 code yet, but it appears in this regard the AFCI requirements on the branch circuit have been relaxed. You installed 20 amp circuits so when using NM-B cable you can have up to 70 feet of branch circuit feeder before the AFCI receptacle (50 feet on a 15 amp circuit).

I'm not a code monkey by any means but my understanding is that the protection requirement is for the outlets, not the circuit,
Earlier codes required the entire circuit to be protected when using NM-B cable. There were some exceptions when using EMT or armored cables for the branch circuit feeder.
 
  #12  
Old 01-11-16, 11:12 AM
Forum Topic Moderator
Join Date: Sep 2005
Location: USA
Posts: 4,711
Received 29 Votes on 28 Posts
I can't add much to the AFCI discussion, but...

I'm considering hardwired baseboard heaters on a 20A three wire 220 circuit.
All (or most at least) baseboard heaters run off 240v, not 240/120, so you only need to wire them with 14/2 or 12/2 (with ground) cable. No need to run three-wire cable if you go this direction.
 
  #13  
Old 01-11-16, 11:32 AM
Member
Thread Starter
Join Date: Dec 2013
Location: USA
Posts: 8
Received 0 Votes on 0 Posts
@Casual Joe:

hmmmmmmmmmm. Now I'm a little confused, because my locality isn't actually on 2014 NEC, but 2011. Perhaps the local office has decided they're just not concerned in light of the 2014 updates, despite their officially being on 2011. But it would certainly be unusual for a gov't office to be that... um... forgiving!

@Zorfdt:

Great point about not needing a neutral for that circuit. However, I think I would need one if I want to have a wall thermostat, correct?
 
  #14  
Old 01-11-16, 11:36 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 10,092
Received 29 Votes on 23 Posts
@Casual Joe:

hmmmmmmmmmm. Now I'm a little confused, because my locality isn't actually on 2014 NEC, but 2011. Perhaps the local office has decided they're just not concerned in light of the 2014 updates, despite their officially being on 2011. But it would certainly be unusual for a gov't office to be that... um... forgiving!
The Mike Holt Forum link you provided was on the 2014 code so I assumed that was the code you were under. Keep in mind that all codes are local and can also have requirements added or taken away by amendment/ordinance.
 
  #15  
Old 01-11-16, 01:10 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
However, I think I would need one if I want to have a wall thermostat, correct?
No. If you used a line voltage thermostat which is common for baseboard heaters it is just a switch and needs no neutral. If by wall thermostat you mean a low voltage thermostat such as NEST they use 24 volts derived from a transformer. You would use a transformer with a 240 volt primary and 24 volt secondary.
 
  #16  
Old 01-11-16, 01:18 PM
Member
Thread Starter
Join Date: Dec 2013
Location: USA
Posts: 8
Received 0 Votes on 0 Posts
Back to the original subject:

Again, just to be clear to all reading: each heater is, on its own, tripping TWO AFIC devices simultaneously. I saw where PJmax said that load on one circuit can trip a protection device on another circuit if the wires are run parallel to each other, and it turns out that a small portion of the homeruns for each of these circuits do run parallel to each other. However, there is another AFCI bedroom circuit running parallel along the same homerun, and that AFCI is not tripping.

My question is: if these two circuits are sharing the same tandem breaker at the load center, could this have something to do with the problem (despite the fact that the breaker is "upstream" from the AFCI receptacles)?
 
  #17  
Old 01-11-16, 02:43 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
As suggested by Tolyn suggested first replace the affected AFCIs. If possible I'd look for a different brand.
 
  #18  
Old 01-11-16, 03:50 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,955
Received 33 Votes on 28 Posts
I didn't read the whole thread, but if there is a loose connection in the circuit that trips the afci will see the arc from the high load of the heater.
 
  #19  
Old 01-12-16, 09:30 PM
Member
Thread Starter
Join Date: Dec 2013
Location: USA
Posts: 8
Received 0 Votes on 0 Posts
@pcboss:

Could that loose connection be anywhere in the circuit, eg, in other outlets? Or would it have to be in either the receptacle being used by the heater or the AFCI receptacle?
 
  #20  
Old 01-13-16, 09:41 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 10,092
Received 29 Votes on 23 Posts
Could that loose connection be anywhere in the circuit
Yes, it could be anywhere downstream of the AFCI receptacle.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: