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Jim Benante
08-13-2006, 11:39 PM
A few weeks ago my wife mentioned the microwave was broken. It is an above the stove unit with exhaust for the stove tops. I wasn't too upset as they aren't that expensive. Then a few days later she tells me it is working again. Then a few days later no dice again. My FIL was in town shortly thereafter and we tested things with a multimeter. We got a reading of 72-73 volts and I hooked up a circuit tester and it read a code for open neutral. We went to the panel and toghtened all the neutral connections. I then tested the other outlets on the circuit. All outlets tested out at 120V except one that wasn't being used, it read 73V. When tested from hot to ground I got 120V so again a problem with the neutral. This is where it gets weird. So we put the outlets back in the wall and whalla 120V. Microwave has power and is ready to go. My FIL was just leaving town at this point in time so he looks like the hero. Well about 30 minutes after they left it was lunch time and my wife was preparing lunch for my son. Microwave not working. A few days pass and after some nagging about getting an electrician I take another stab at it. I disassemble the two culprit outlets and reassemble. 120V on both microwave back in order. A few hours later 73 volts again at both outlets.

Can anyone tell me what to do or where my problem is. There are several other outlets on this circuit and they work just fine. I am confused and tired of this rollercoaster.

Randy Meijer
08-14-2006, 1:49 AM
For a start, I'd spend 3 bucks and buy a couple of new outlets. Cut off about a half inch of the wire going to each outlet to be sure you have a fresh connection at each outlet. It's probably only the upstream outlet that is a problem; but it doesn't cost much to change out both. It is also possible that both of the 73 volt outlets are OK and the problem lies with the wire or outlet upstream of those two.

Jim Becker
08-14-2006, 9:51 AM
I agree with Randy...likely a bad connection on the outlet, especially if they are "cheap, push-in, back-wired" outlets. If changing the physical outlets doesn't fix the problem...call a qualified electrician post-haste. (And don't forget to kill the breaker when you are swapping out the outlets!)

Kent Fitzgerald
08-14-2006, 10:00 AM
Well, you're smarter than I am - I once replaced every receptacle and connection on a flickering circuit before I checked the neutral connection in the panel.:rolleyes:

I agree with Randy that the problem is probably at the next upstream receptacle. If you have push-in backwired receptacles, they're almost certainly the culprit. Replace with wire nuts and pigtails.

Lee Schierer
08-14-2006, 12:50 PM
I just encountered the same thing with a bathroom outlet at my son's house. Sometimes it would work and sometimes it would not,yet the circuit breaker and upstream ground fault was always on. We found the problem to be the push in wire connection on the back of the receptacle. I moved the wires to the screws and everything works fine. I hate push in wire connections.

Jim Benante
08-14-2006, 1:37 PM
Thanks for the help. I will buy a few new outlets. I had kind of planned on trying that anyway.

One thing to mention is that I did these outlets about a year ago and they are the nicer looking type, but are push in. I just don;t get why after a year I am having problems all the sudden.

I'll let you know the outcome.

Don Baer
08-14-2006, 1:43 PM
One thing to mention is that I did these outlets about a year ago and they are the nicer looking type, but are push in. I just don;t get why after a year I am having problems all the sudden.


The problem with the pushin type is they rely on a mechanical tension to carry current. They don't realy grip that tight and with time the spring loaded clips get weak. They are quick to use but they are not as good to use as strewing the wire in.

Kent Fitzgerald
08-14-2006, 2:48 PM
No offense intended, but I've seen cases where receptacles were miswired by pushing the wire into the (rectangular) release slot, rather than the (round) terminal hole. The result is a very weak connection that will sort of work, for a while. It's a fairly easy mistake to make (and one more reason not to use push-in connnections).

Jim Becker
08-14-2006, 3:24 PM
There are cheap back-wire outlets and good back-wire outlets. The difference is money and design. The better ones (which I like) are commercial grade and secure the wire with a screw...you just don't have to deal with getting the right "curve" on the wire first like you do with the normal screw terminals. And they are maybe two or three bucks more each than the cheapies...not a whole lot when you consider things.

For the record, I had a very similar problem to the OP in my previous residence in an upstairs bedroom. The builder's electrician used the cheap push-in, back-wired receptacles and after a few years a few just didn't grip the wire very well, causing really strange and intermittent problems very much like described in post one above. At that time, it took me a long time to figure things out as I was "new" to home improvement...and it was frustrating!

Jim Benante
08-14-2006, 5:27 PM
I agree that the push in are not the way to go. I bought these without considering that they were pushins. I liked they way they look. They are the squared off type and are a nice clean white. They look great and I had used them in another room and a another residence without problems. Maybe I can find some heavy duties that also look nice or maybe they have this same type in a heavy duty type.

It really has to be the plugs as I was able to get it working with only messing with the plugs.

Kent-No offense taken, but I do have them wired correctly.

Chris Padilla
08-15-2006, 4:52 PM
I agree with Randy...likely a bad connection on the outlet, especially if they are "cheap, push-in, back-wired" outlets. If changing the physical outlets doesn't fix the problem...call a qualified electrician post-haste. (And don't forget to kill the breaker when you are swapping out the outlets!)

I believe the correct term for the "cheap, push-in, back-wired" receptacles is back-stabbed.

The kind you want and others have referred to are called back-wired. These have a hole you insert the wire into (use the strip gauge) and then you turn a screw that literally clamps the wire in place. How hard it clamps depends on how much torque you put on the screw.

Jim Becker
08-15-2006, 5:30 PM
I believe the correct term for the "cheap, push-in, back-wired" receptacles is back-stabbed.

That's why you're a REAL engineer and I'm a mere consultant... ;)

And...I really agree with your terminology! Very true. Very true.

Rob Russell
08-15-2006, 8:08 PM
I believe the correct term for the "cheap, push-in, back-wired" receptacles is back-stabbed.

The kind you want and others have referred to are called back-wired. These have a hole you insert the wire into (use the strip gauge) and then you turn a screw that literally clamps the wire in place. How hard it clamps depends on how much torque you put on the screw.

Chris,

Couldn't have said it better myself.

Rob

Chris Padilla
08-16-2006, 11:24 AM
Chris,

Couldn't have said it better myself.

Rob

LOL! I was expecting yet another correction from Mr. Rob "NEC" Russell but I guess this time, I learned correctly (and most importantly, remembered correctly) and thus received, shall I say, adulation?! :p

:D :D

Rob Russell
08-16-2006, 1:28 PM
LOL! I was expecting yet another correction from Mr. Rob "NEC" Russell but I guess this time, I learned correctly (and most importantly, remembered correctly) and thus received, shall I say, adulation?! :p

:D :D


"adulation" ... ackkkk, cough, choke ... something's stuck in my throat ... can we just go with "ya done good"? :D :eek: :D

BTW, back-stabbed vs. back-wired isn't an NEC issue, it's more of a device quality issue.

Jim Benante
08-16-2006, 2:29 PM
Well I hope to buy the replacement outlets this evening. I haven't had time the past few days. I am training for a charity bike tour. It is called the MS 150 and is set up to gathe research funds for multiple sclerosis research. 150 miles in two days. The past 3 weekends I have given up a full day to riding. And I ride about twice during the week before (commute to work) or after work (group rides). I also am doing a small 2 story addition to the house. I hate when little things go wrong when you want to focus on the big project that you started and fear you won't finish before the wet winter starts here in WA. In addition, I have a 1 year old son and the suspect outlets are in his room so late night home repair (only time I seem to have available) is out of the question. I am definitley over extended, but I can say I am enjoying the hectic summer anyway.

I'll let you know how the replacement outlets work out. And maybe I'll post some pics of my addition in a new thread. I finished the concrete work last week. Footer, wall, and slab are in place and waiting for me to figure out the framing that will rest on it.

Jim Benante
08-19-2006, 12:56 AM
Okay, I replaced two outlets which are between the panel and the microwave. Now I get like 6 Volts. I had forgot to mention that this is where I had left off after the redo of the old plugs. So my outlet reader thingy says hot/ground reverse. They are not reversed. I have one more outlet that could be effecting the situation that I will change next. How did I go from open neutral to hot/ground reverse when everything I can see is the same wiring that worked for over a year with no hiccups. I am confused. I'll try the last outlet tomorrow. Could it be the old light fixture that is also on the circuit. It is about 20 years old and has aluminum foil inside of it. I wanted to replace when I painted the boys room, but my wife likes old things.

Randy Meijer
08-19-2006, 3:41 AM
An old pilots saying is "trust your instruments." If your tester says you have a reversed hot/ground, I would assume that it is true and that you have missed something. This is getting very close to the point where you need to call in an electrician unless you are very confident in your electrical skills and are satisfied that this is a problem you can handle. A reversed hot/ground is not good!!

If it were me, I would disconnect every wire to every switch, light and receptacle on the circuit and start from scratch.
(I assume that you have checked your other circuits and they all check out OK?) You might also want to check the attic or basement for any junction boxes in this circuit that might have a wire connection that is failing or incorrect. You might also want to check for any damage to the wiring that may have been caused by rats or squirrels.

Then I would rewire each component...one at a time... starting with the one closest to the breaker box(electrically) and test it thoroughly. Add and test components, one at a time, until you get to the point where the tester says there is a problem. By then, you should have enough information to determine what the problem is.

From your comment about the light, I'm assuming yours is an older house. Years ago, I had some funny things going on at my older home that I couldn't get a handle on and it turned out to be a bad connection in the neutral conductor of the drop coming from the electric company. Symptoms were not similar to yours; but a poor neutral can cause all sorts of funny stuff. Just something to keep in the back of your mind. I think that if you take a systematic approach to troubleshooting your problem, a solution will be forthcoming. Good luck!!

Randy Meijer
08-19-2006, 3:49 AM
Okay, I replaced two outlets which are between the panel and the microwave. Now I get like 6 Volts. I had forgot to mention that this is where I had left off after the redo of the old plugs. So my outlet reader thingy says hot/ground reverse. They are not reversed. I have one more outlet that could be effecting the situation that I will change next. How did I go from open neutral to hot/ground reverse when everything I can see is the same wiring that worked for over a year with no hiccups. I am confused. I'll try the last outlet tomorrow. Could it be the old light fixture that is also on the circuit. It is about 20 years old and has aluminum foil inside of it. I wanted to replace when I painted the boys room, but my wife likes old things.

Is the 6 volts at the new outlets or at the microwave or both??

Is the light up or downstream from the two new outlets?? Is it burning brightly when you turn it on??

What does the 1 year comment mean? Has this circuit been reworked??

Kent Fitzgerald
08-19-2006, 8:43 AM
Jim, the problem still most likely an open neutral, in which case the flaky test readings aren't at all surprising. Do you have any loads plugged into the affected circuit? That would throw your readings out of whack.

It's also possible that you're seeing "phantom" voltages. In AC circuits, a disconnected conductor can act like an antenna, and carry a tiny but measurable (with a sensitive digital meter) current. Likewise, the "hot/ground reverse" indication on the receptacle tester just means that a voltage is present between the neutral and ground - not necessarily a physical reversal of the wires. The neon bulbs in the tester are sensitive enough to pick up a phantom voltage on the neutral.

Unfortunately, you're back to step 1 on solving the problem. Definitely check the connections at all the remaining fixtures on the circuit. If that doens't solve it, you may have a broken wire, which is harder to find and fix. Most likely spot for a break is right where wires enter the fixture boxes. Have you done any drilling in the walls recently that could have hit a wire?

Jim Benante
08-20-2006, 1:27 PM
Jim, the problem still most likely an open neutral, in which case the flaky test readings aren't at all surprising. Do you have any loads plugged into the affected circuit? That would throw your readings out of whack.

It's also possible that you're seeing "phantom" voltages. In AC circuits, a disconnected conductor can act like an antenna, and carry a tiny but measurable (with a sensitive digital meter) current. Likewise, the "hot/ground reverse" indication on the receptacle tester just means that a voltage is present between the neutral and ground - not necessarily a physical reversal of the wires. The neon bulbs in the tester are sensitive enough to pick up a phantom voltage on the neutral.

Kent you got it right. It was an in fact an open neutral at a different outlet. The circuit tester must be as sensitive as you stated to be showing hot/ground reverse. I am no electrician, but I knew I would never screw up that bad to reverse the hot and ground.

I was misreading the direction of the circuit and so the one outlet I hadn't checked was actually pre-funny stuff outlets. It was a back stabbed(no bolt to screw in to hold it in place) vs. back wired. A neutral popped loose. Not sure why after a year it pooped out, but it was no longer stabbed into the back of the outlet. I replaced the outlets with the back wired types and all is well.

Thanks for all the advice and help. No longer do we need the spare microwave taking up valuable counter space.

Jim

Kent Fitzgerald
08-20-2006, 9:15 PM
Glad to hear it's fixed!

Chris Padilla
08-21-2006, 12:21 PM
Awesome! "need a THUMB-UP" sticky here! :)

Randy Meijer
08-22-2006, 3:59 AM
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:D :D :D