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-   -   Stab-in connections, ceiling fans, and computers (http://www.diychatroom.com/f18/stab-connections-ceiling-fans-computers-7321/)

tima2381 03-22-2007 10:59 PM

Stab-in connections, ceiling fans, and computers
 
I installed a new Hunter ceiling fan a couple of days ago, and immediately I noticed that the fan pull chain didnít reliably control the fan speed. Perhaps 1 out of every 5 pulls would change the speed, and 1 out of 10 would trip the AFCI breaker. The fan is in my home office, and my computer is on the same circuit as the fan, connected to the outlet through an APC 1500VA UPS. The computer normally draws 300-400W, and the fan is rated at 220W, so I donít see how I could have been overloading the 15A circuit. This morning, I did some more testing, starting by unplugging the UPS from the wall outlet. The fan worked fine. Then I plugged the UPS in again, and the fan continued to work fine. Then I pressed the power switch on my computer, and the circuit breaker tripped immediately. To add to the mystery, the computer wasnít on the night before while the fan was acting up. As a final test, I unplugged the UPS and hooked 500W of lighting up to a surge suppressor and plugged it into the outlet I was using for the computer. That worked fine.

This is a new house built in late 2006, so one would think the wiring would be all good. The outlets check out fine on my Sperry outlet tester, and I didnít find any problems with my voltage tester. However, when I removed the plate for the dual wall switch (one to control the light, one to control the fan), I found the electrician had back-stabbed the wires. He also didnít connect the ground wire to the green screws on the switches. (Thatís another question; thereís no voltage between the hot or neutral and the ground and metal fronts of the switches, so how big a problem is this?) When I took the cover off the wall outlet for my computer, I found he had also back-stabbed the 2 black and 2 white wires hooked up to this outlet, though the ground was properly connected to the green screw.

Iíve read that the stab-in connections can be very unreliable, particularly when computers are involved, so I said what the heck, Iíve got the plates off, and I might as well reattach the wires using the screws. So I did, and to my surprise, itís all stable and working properly now.

My question is, does this story make sense? Can you explain what was wrong and why converting the stab-ins to screw-ins fixed the problem? Based on the problem description in my first paragraph, is this something an electrician would have considered right away? I figured it had to be a defective fan, but swapping the fan was going to be a lot harder than rewiring the switches and outlets, which I felt I should do anyway once I discovered they were back-stabbed. It would be wonderful if I had something really compelling and ďofficialĒ to take to the builder concerning this problem.

jwhite 03-23-2007 04:15 PM

No, this story does not make sence, unless one of the stabs was burning up, and then it would not explain the pull chain on the fan not working.

Sounds like a coincidence. The real problem will surface again.

JohnJ0906 03-24-2007 07:56 AM

I agree, unless one of the stab-ins that you examined was loose.

tima2381 03-24-2007 02:24 PM

Quote:

Originally Posted by jwhite (Post 38124)
No, this story does not make sence, unless one of the stabs was burning up, and then it would not explain the pull chain on the fan not working.

Sounds like a coincidence. The real problem will surface again.

You are correct, sir. This morning I flipped the wall switch to turn the fan on, and the AFCI breaker tripped. This was happening maybe 1 out of every 10 flips. (The UPS was unplugged, taking it out of the equation.) I swapped the light fixture/pull chain apparatus with a new one and observed the same thing. The wiring in those parts appeared OK to the eye, so I took the whole fan down. My connections in the ceiling box all appeared solid, and I'm getting 120v between the two hots and the neutral and ground, and nothing between the neutral and ground. The only unusual thing I noticed was in the wiring of the harness that exits the bottom of the fan motor. The wires are tied into a loose knot, and there is some brown gunk on the white wire where it is wrapped around the other wires. Here's a picture of the harness:

http://i169.photobucket.com/albums/u...93/Harness.jpg

And here's the neutral after I pulled it out a bit to separate it from the knot:

http://i169.photobucket.com/albums/u...93/Neutral.jpg

Does this suggest anything to you? Would you go ahead and try a new fan? I'm inclined to try a new fan, and if it doesn't work, then clearly I will be out of my depth and need to call an electrician.

jwhite 03-25-2007 07:30 AM

The problem is most likely that the AFCI breaker is too sensitive. Since they have been required there have been constant complaints about them not working as well as they should.

Loads that draw large amounts of current on start up, like vacume cleaners and fans (on high) will make a spark at the switch when it is turned on. The AFCI sees this spark and trips.

I am glad that my current work is in the commercial and industrial market where AFCI are not yet required. IMHO they do not do what they are intended to do, and should not be required until the technology is perfected.

As a licenced electrician, it would be unethicle for me to suggest that you violate the laws, so I refuse to suggest that you remove the afci breaker and install a standard one in it's place.

tima2381 03-26-2007 12:29 AM

Quote:

Originally Posted by jwhite (Post 38250)
The problem is most likely that the AFCI breaker is too sensitive. Since they have been required there have been constant complaints about them not working as well as they should.

Loads that draw large amounts of current on start up, like vacume cleaners and fans (on high) will make a spark at the switch when it is turned on. The AFCI sees this spark and trips.

I am glad that my current work is in the commercial and industrial market where AFCI are not yet required. IMHO they do not do what they are intended to do, and should not be required until the technology is perfected.

As a licenced electrician, it would be unethicle for me to suggest that you violate the laws, so I refuse to suggest that you remove the afci breaker and install a standard one in it's place.

Jeez, I hope that's not it. If that were the problem, I don't understand how it accounts for my initial problem with the pull chain. Also, the power-hungry computer never tripped the breaker in the 100 or so times I turned it on prior to installing the ceiling fan. It did trip the breaker the one time I turned it on while the ceiling fan was running. Hopefully I'll have better luck with a new fan.

Here's another curiosity (to me, at least). I reviewed some pics I took in the framing stage, and there was Romex running from the computer outlet to an outlet along the adjoining wall. There was also Romex running from the attic to each of these outlets. There are two outlets opposite these which are connected to one another but only one receives wire from the attic. What's the reason for the former, and what's the difference between it and the latter?

jwhite 03-26-2007 04:46 AM

A defective pull chain could also cause your problem.

As for the wires. I cant grasp the picture of what is going on, but my guess is that one of line from the panel and the other load to other devices.

tima2381 03-26-2007 12:51 PM

Quote:

Originally Posted by jwhite (Post 38321)
A defective pull chain could also cause your problem.

As for the wires. I cant grasp the picture of what is going on, but my guess is that one of line from the panel and the other load to other devices.

I was thinking a "line from the attic" means "from the panel", but I suppose Outlet 1 could receive the line from the panel, a line could connect Outlet 2 to Outlet 1, and then a line could exit Outlet 2 back into the attic to feed something else. What would it mean, though, for Outlets 1 and 2 to each receive lines from the panel and also be wired between themselves?

jwhite 03-26-2007 05:56 PM

Quote:

Originally Posted by tima2381 (Post 38370)
What would it mean, though, for Outlets 1 and 2 to each receive lines from the panel and also be wired between themselves?

That someone goofed up.

tima2381 03-26-2007 08:27 PM

Quote:

Originally Posted by jwhite (Post 38408)
That someone goofed up.

How would the outlets behave?

jwhite 03-27-2007 04:27 AM

If a circuit were backfeed to two breakers on different phases, a breaker would trip as soon as the second of the two breakers was turned on.

If a circuit were backfeed to two breakers on the same phase there could never be a problem, or it may never be noticed. It would however take turning off more than one breaker in order to get the power turned off to that circuit. (this is a safety hazzard)

With the second example a simple fault in the circut can cause a more serious problem. For examle an open neutral on one of the legs. Now the current is not traveling to and from the panel in the same cable, which can cause EM interference and eddie currents. Especially if metal boxes are involved. This can become a very serious hazzard.

mikemy6 03-27-2007 11:10 AM

Yes you really need to know if those are both line or line+load wires to the attic I think you have one of those three light plug in testers and this would appear normal if the lines are in phase.
Its 14AwG wire and 15 Amp outlets correct?
I have seen 14 with 20's and they dont seem to hold the stab as well.

tima2381 03-31-2007 10:21 PM

Quote:

Originally Posted by jwhite (Post 38321)
A defective pull chain could also cause your problem.

I installed a new fan yesterday, same make, same model, and it worked flawlessly from the start. So it appears the defect was in the original fan and/or lighting/control assembly. That said, I'm not entirely happy with it, as it does produce an annoying hum, just like the first one. I found a thread on another board mentioning the same thing:

http://forum.doityourself.com/showthread.php?t=262321

I think I may have to look into some higher-end fans...

tima2381 03-31-2007 10:23 PM

Quote:

Originally Posted by mikemy6 (Post 38523)
Yes you really need to know if those are both line or line+load wires to the attic I think you have one of those three light plug in testers and this would appear normal if the lines are in phase.
Its 14AwG wire and 15 Amp outlets correct?
I have seen 14 with 20's and they dont seem to hold the stab as well.

Yes, it's 14AwG and 15 amps. The outlet checked out fine with the plug-in tester and also my voltmeter, so I guess I jumped to the wrong conclusion as already described. :)

jwhite 04-01-2007 05:38 AM

Quote:

Originally Posted by tima2381 (Post 39182)
I installed a new fan yesterday, same make, same model, and it worked flawlessly from the start. So it appears the defect was in the original fan and/or lighting/control assembly. That said, I'm not entirely happy with it, as it does produce an annoying hum, just like the first one. I found a thread on another board mentioning the same thing:

http://forum.doityourself.com/showthread.php?t=262321

I think I may have to look into some higher-end fans...


does it wobble? If it is not wobbling and just humms, the only option is to buy a higher quality fan. If it does wobble then you can try balancing first. there should have been directions for balancing in the box. it takes a long time, but is worth the effort.


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