I got a strange thing happening in my son’s new bedroom: When I turn on my Makita LS1013 it will trip the breaker. When I turn on the Craftsman shop vac first and then the Makita LS1013 the breaker will not trip. Who can explain that to me. Both are plugged into the same receptacle. The room is fed from a sub panel on the same floor. The bedroom has a 15 amp arc fault interrupter. The light (60 watt bulb) and the receptacles are on the same breaker.
I would like to know why this happens.
Martin
Replies
The saw is arcing. The vac acts as a noise suppressor.
Thanks Dan. I don't know why I didn't come up with that.Martin
Edited 12/17/2006 12:17 am ET by myhomereno
"The saw is arcing...the vac acts as a noise suppressor..."
Yeah Dan, I agree with you that the saw is arcing on start-up....and I agree that by running the vac first before starting the saw, it must be suppressing the AFCI...but noise suppressor?...I don't think so.
If memory serves me right, AFCI's don't trip on noise..they trip when they detect amperage leaks.
Wanna try again?
Davo
Branch Feeder AFCI's have two trip mechanisms (beside overcurrent).One is a ground fault leakage test. Much like GFCI's, but they trip at 30 ma, which is way too high for personal safety.The other is detecting a parallel arcing signature. IIRC it is 70 amps peak. Now I have absolutly no idea of how that arcing signature is defined or how it is detected. Nor how different brands of AFCI may see a signature differently.But it has to be more than on just peak current. Many motor appliances with hit that on the starting peak.Apparntly the lower current of the vac is enough to help mask the way that the AFCI see the peak current so that it is not seen as an arc.That is the "noise" tht Dan was talking about..
.
Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I was reading a trade magazine the other day, and they said that the 2008 NEC may require AFCI's for all branch circuits, not just bedrooms. I wonder how that's going to work out...
we can start by throwin out all our power tools,. since they won't work ......and go out and buy stock in Sq D , C-H, et al.
.
.
.Wer ist jetzt der Idiot
?
For the SQ QO breakers I have a good fix.SQ makes what is called a Molded Case SWTICH. It is switch rated at 60 amps carring current. It is a two pole.I know one electrican that uses then on motor circuit where they keep blowing breakers on startup. After verifying that wiring is in good shape he used it to keep the motor running long enough to get an reading on a clamp on.Sq makes an A/C disconnect uses them. I went the other way and removed the switch and replaced it with the appropriatedd rated breaker.Found out that my feeder and breaker was way oversized for the A/C unit and the panel uses GTE(Zinsco)breakers so going with a breaker disconnect was a cheap way to fix it..
.
Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Worse it they are calling for combination AFCI's which trip on both parallel and series arc detection. AFAIK it there are none yet available.I am afraid that there are going to be a lot more false tripping problems.The 2005 NEC also requires them on under the starting in 2008 for the bedrooms..
.
Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I hope the code also calls for putting the panel in the living room. You're gonna need plenty of clear access to it for all the resets.
It'll also be nice paying 10 times the price to outfit the panel with all those breakers.
Edited 12/17/2006 4:58 pm ET by MSA1
LOL....View Image
I think that I have found an invention that I can retire on.Make a motoriezed device that when it cycles it hits all of the reset buttons at once.Then have wireless transmitter that plugs in one receptacle on each circuit.As soon as one trips, it will automatically reset it..
.
Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Maybe you just need to invent a battery-powered saw.
People never lie so much as before an election, during a war, or after a hunt. --Otto von Bismarck
Do I get any inspirational residuals?
Well at least an honorary dog bone.Maybe something more substantial after I turn my first profit on it..
.
Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Did you just steal my milkbones? I thought I nailed it first.
Spheramid Enterprises Architectural Woodworks
I have irriatable Vowel syndrome.
Bill,
I gotcha...thanks.
I was down at my local electrical supply store today and asked the store's electrician what he thinks about them. This guy is a state licensed sparkie, and just "moonlights" at the supply store a few days each month. He told me he hates the AFICs.
He went on to say that by code he always installs them...and a few weeks after the final inspection has been made, he usually gets a call from the homeowner to asking him to remove them and replace with regular breakers; which he does. Everything I have heard and or read about these breakers indicate they are nothing more than a NEC rip-off. More money for a product that doesn't really perform the job its supposed to do...at least not in relation to the price paid out for these devices.
Davo
The saw has an Ele. brake, it arcs to stop the blade. The suppression is the vac pulling a constant draw and does interupt the built in arc protection in the circut, by keeping a constant draw. Just the saw, reads as an interuption to the breaker, and it flips off.
Spheramid Enterprises Architectural Woodworks
I have irriatable Vowel syndrome.
Yep, you got it. My LS1013 trips the bedroom AFCI's too. Took me awhile to figure that one out. Almost called and yelled at the electrician but since he's a nice guy I figured I oughta do a little research before picking up the phone. :)View Image
Ummmm? Why are you sawing in the bedroom? Showing the Missus a new blade wobble?
Spheramid Enterprises Architectural Woodworks
I have irriatable Vowel syndrome.
The sound lulls me to sleep.
Naw, when we put the second floor on our house that's the room I chose to set up in for trim-out as it is the largest of the new rooms. View Image
LOL..I know what ya mean.
Spheramid Enterprises Architectural Woodworks
I have irriatable Vowel syndrome.
The first time I experienced this I kept tripping the bedroom breakers with a Bosch router. I would take the router outside the room and try it on another circuit, no problem. I was certain there was an electrical problem in the almost finished remodel I was working on and was starting to lose it. Luckily our electrician was around to explain the problem.
I'm sure what they said above is true, but in summary, my thought is that AFCI's just aren't really compatible with power tools. So, no power tools in the bedroom. I think it's a plot by the Baptists. :-)
Edited 12/17/2006 8:53 am ET by Matt
15 amp breaker???!!!
time to stick a crow bar in your budget and properly rewire....
"Dogs don't follow an emotional leader. They follow the dominant leader. We are the only species that follows an unstable leader. "
Cesar Millan, The Dog Whisperer, in an interview in National Geographic Magazine