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#66846 - 06/20/06 01:42 PM Branch Circuit TroubleShooting  
workn26  Offline
Junior Member
Joined: Dec 2005
Posts: 8
Hello all,

I just got a call from a friend of mine who is having a problem with a branch circuit in his house. It seems that he was using his home computer printer to print out a long queue of player lists for the basketball team that he coaches when the printer went dead. He called me and explained what I just told you. This is basically the conversation between the two of us:
Me: Do you have your printer & computer plugged into the same outlet?
Him: Yes.
Me: What room in your home is the printer & PC?
Him: My bedroom.
Me: Can you turn on the lights in your bedroom?
Him: No! I didn't realize that until now!
Me: Have you tried to reset the breaker protecting the bedroom brach circuit?
Him: Yes; it isn't tripped at all.
Me: Are you positive? Turn it off and on.
Him: I did. No change.
Then, after about five minutes,while we were talking he told me that the lights went back on in his bedroom and his printer is warming up.
Me: Unplug your printer and PC now!
Him: Why? Everything is OK now.
Me: Keep your printer & PC uplugged and don't use any devices connected to that branch circuit until I get there tomorrow.
Him: Well...alright, but why?
Me: Do you smell anything strange (besides yourself) in your bedroom & the room where your panel is located. In particular, do you smell anything even remotely like something burning; even if it's the kind of ozone smell that your hair dryer would make?
Him: No.
Me: I'll be there tomorrow. Turn the breaker protecting the branch circuit off until then.

I'm thinking that there could be a loose connection somewhere in the branch circuit that could possibly be good enough under normal usage, but heats up and disconnects the circuit while his printer is running for extended periods (particularly due to the harmoics emminating from his printer via the nuetral that could heat up considerably).

Anyone want to dive in and give me any extra possibilities on this one.
I'd appreciate it.

[This message has been edited by workn26 (edited 06-20-2006).]

[This message has been edited by workn26 (edited 06-20-2006).]


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#66847 - 06/20/06 02:51 PM Re: Branch Circuit TroubleShooting  
zero76  Offline
Joined: Oct 2004
Posts: 26
The first thing i have to wonder, is he absolutely certain there wasn't a power outage when it happened? Typically, a bad connection doesn't just make or break cleanly without some other indication such as lights flickering etc. unless the fault is inside the breaker. First,i would remove the panel cover and look for loose or discolored connections, then try some resitance tests with the power off. If nothing shows up there plug in a large load such as a portable space heater and check amperage on that ckt. and look to see if the bedroom light is flickering.

Are you a liscensed electrician? If not then i suggest you consider calling one.


#66848 - 06/20/06 03:10 PM Re: Branch Circuit TroubleShooting  
workn26  Offline
Junior Member
Joined: Dec 2005
Posts: 8
Thanks for your reply Zero,

Yes, I am a licensed electrician.
I asked him if he had power in the rest of the house when his bedroom circuit was out, and he said yes. I'm leaving for his house in about an hour and am planning on going by Home Depot and buying a 20 amp breaker in case his connections looked good and a resistance test proved accepatable. I recently purchased a Fluke 43B Power Quality Analyzer and plan on testing the entire brach circuit from the printer outlet back to the panel; outlet by outlet.

What do you think?



#66849 - 06/20/06 03:25 PM Re: Branch Circuit TroubleShooting  
LarryC  Offline
Joined: Jul 2004
Posts: 783
Winchester, NH, US
This is just SWAG, but check to see if the branch circuit devices are daisy chained, and if so, are they wired by the plug and pray backstabs. I'll wager that a wire has broken off at or near the backstab.


#66850 - 06/20/06 04:01 PM Re: Branch Circuit TroubleShooting  
Radar  Offline
Joined: Apr 2004
Posts: 349
Los Angeles, CA
Me: Can you turn on the lights in your bedroom?
Him: No! I didn't realize that until now!

Overhead lighting or plug-in lamps? I'm kinda siding with Larry here, except you ought to have a look under the desk that the computer is sitting on. Maybe a plugstrip or some such plugged in back there than might be disturbed when he sits back and stretches his legs out while waiting for the printer to finish. Dumb, I know, but it happens.


There are 10 types of people. Those who know binary, and those who don't.

#66851 - 06/20/06 04:10 PM Re: Branch Circuit TroubleShooting  
workn26  Offline
Junior Member
Joined: Dec 2005
Posts: 8
Larry & Radar,

That ain't SWAG or dumb at all. In fact, I'm hoping that that is exactly what the problem is; something simple and so obvious as to be overlooked. My worst fear in this situation is that there is a loose connection that could be arcing. I know that his house is over 40 years old and ther are no arc fault breakers in his panel (I asked him to visually discribe the breakers).I'm an industrial electrician, and I can't tell you how many simple problems have cost lots of $$$$$ in man hours because the electician was way too "smart" to start looking for the simplest solution.

Thanks again to all of you; I'm off to the source to find the culprit. I'll post my findings here tonite.

Much obliged,


[This message has been edited by workn26 (edited 06-20-2006).]


#66852 - 06/20/06 08:19 PM Re: Branch Circuit TroubleShooting  
Lostazhell  Offline
Joined: Feb 2004
Posts: 1,431
Bakersfield, CA (Originally Or...
Typically the first thing I'll do after checking the panel, is go around with a plug-in tester and "wiggle" the outlet a bit. If it's a loose connection (which for me at least, it usually has been) the lights will flicker off and on when you do this on the culprit outlet.

One other note, if his panel is Zinsco, pull the breaker and check for pitting on the busbar/breaker contact. Zinsco contacts will heat up under load and spread apart from the busbar due to dirt, grime, missing cats, etc. and cause a circuit to fail, the contacts will cool after a while and grab again. Kinda cyclng itself.

#66853 - 06/20/06 08:47 PM Re: Branch Circuit TroubleShooting  
e57  Offline
Joined: May 2003
Posts: 2,876
I don't blame you for telling him to kill the circuit.... I have told people to find the main sometimes, and leave it off until I get there. Once arrived to a service call sortly after the fire dept got there once. But the damage had been done before they even called me.... You canT troubleshoot over the phone for those types of things.

Personly, due to several incidents of having to repair damage caused by reconnect of POCO faults, if I have the chance I shut off my own main and wait until I have checked it to turn it back on.

Otherwise, I'll ditto Randy (Lostashell) and Larry's advice.... But it could be any number of things....

[This message has been edited by e57 (edited 06-20-2006).]

Mark Heller
"Well - I oughta....." -Jackie Gleason

#66854 - 06/21/06 07:31 AM Re: Branch Circuit TroubleShooting  
workn26  Offline
Junior Member
Joined: Dec 2005
Posts: 8
I’m back, but it’s not over yet. This one is for the funny papers.
I’ve got to post here more often; all of you were correct in one way or another. It was amazing to read the posts you guys wrote since I had left for this “service call”. It was the first good laugh that I had all night.

Like I said, I usually service data centers and process plants—I only work residential for friends or on my own house. So, of course I show up over equipped. First I go into (I’m going to call my buddy “Dippy” for the sake of this situation) Dippy’s house and go straight for the panel—it’s a Zinsco. I break out my Fluke 124 dual channel scope and connect to each bus. Whoa!! Right away it was obvious that there was little consideration made or attempt at balancing the loads. I plug in my Ideal breaker tracer into the recep where his PC was plugged into and after going from recep to recep down the line I find out that the guest bedroom circuit where his computer was situated was daisy chained to the master bedroom lights & receps, all of the kitchen lights and half of the receps, the dining room lights and the living room lights & receps. This can’t be.
So I go back to the recep where his PC was plugged into an overloaded power strip with four transformers for various devices along with his printer and plug in my line splitter between the recep & the power strip. Then I hook up my Fluke 43B so I can simultaneously monitor the voltage and amperage. I turn the breaker on and with only some of the lights on (not the PC or any loads on the power strip) the readings are a steady 123 volts and 10 ½ amps with a fairly erratic wave form. I turn on the power strip and then the PC, and although the voltage doesn’t fluctuate much (one good thing), the amps shoot up to 22 amps. I turn on the printer and it goes as high as 28 amps and settles down to 24 ½ amps with some hideous triplen harmonics. I’d seen enough. I sent him to the Home depot to get ten 20 amp breakers (the ones in the panel were all original—if one isn’t tripping, let’s change ‘em all out), two dozen receps-we’re changing them all out too (they looked original also, and some were literally falling apart—he stacked furniture in front of two that had the front portion of the recep completely separate from the rest of the yoke. This was his way of keeping his kids from coming into contact with live parts) and I also told him to pick up three TVSSs for his two PCs and his entertainment center because if lightning were to strike the primary side of the utility somewhere in his neihborhood, his pricy digial equipment could get toasted. So the rest of the night, I mapped out his entire panel to their respective loads and marked them. It got very late, I put everything back to the way it was (didn’t change out any breakers or receps except for the death-receps), told him not to use his computer or plug in the power plant of a power strip he was using for his PC on that branch circuit and said that this will have to wait for the weekend or else call a local electrical contractor for speedier service. I volunteered a choice word regarding his common sense too.
Thirty minutes after getting through my front door at 1:00am following the one hour drive back from his house, my phone rings. It turns out that while he was at the Home Depot, he thought that it would be a good idea to purchase one 30 amp breaker along with the rest of the stuff in case I thought we’d need it. So while I was driving home, Dippy replaced the non-tripping 20 amp breaker with the 30 amp breaker without killing himself and was happy to report that he could run his PC now without the circuit falling out anymore—all is fine he said. I said, for the sake of your children turn off your !*%#@!ing computer, unplug the power strip and call a contractor in the morning. You’re on your own pal, and the next time that I see you I’ll have to think of a very good reason not to kick your ass!

Sorry for the long post, but I needed to talk.
I appreciate all of your replies, fellas.
I’ll definitely visit this forum more often—you all are good.


[This message has been edited by workn26 (edited 06-21-2006).]


#66855 - 06/21/06 09:03 AM Re: Branch Circuit TroubleShooting  
renosteinke  Offline
Cat Servant
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
Not really convinced all the improvements that you made would make much of a difference. Not that they were bad things to do, but is seems that the real problem was 24 amps on a 20 amp circuit.

Maybe not as 'flashy' as getting all those new pieces, but I would want to split that receptacle off from everything else, and run a new circuit all the way to the panel. Yea, I know, that means a lot of crawlng in unpleasant places, and PITA fishing.

No room in the panel? Well, there are solutions for that, too. Of course, they invole lots more work....

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