*
The setting is a million dollar home built by a spec “homeowner/builder” that apparently used equally inept friends and/or relatives to help with various aspects of the construction phase….including electrical wiring! There are two problem areas in the 6400 square foot house, seperate floors but virtually areas that are directly over each other on two floors.
Problem 1: With the lights on in one upstairs bedroom, the lights “dim” when a hair dryer or similar device are turned on in an adjacent bathroom.
Problem 2: A similar action occurs in the first floor laundry room when overhead lights (fluorescent) and powered vent are on and the homeowner plugs in the steam iron. You can audibly hear the powered vent slow down when the iron is switched on.
Problem 1 & 2 are not on a common breaker. We’ve had two electricians look at the problem and they seem to dismiss it as not worthy of their time to correct (ho-hum). They may be daunted by the size of the residence and the number of possibities. Using a “plug-in” circuit tester on outlets to check for polarity problems shows everything is fine in these areas. The house has been occupied for six years with no apparent negatives (fires) other than the annoying “dimming”. In case it is relevant, ther are GFI’s in both these areas also.
Anybody out there care to venture a remedy or some way to narrow the possibilities that could cause these problems?
Much appreciated!
Replies
*
Check to see if your "builder" used cheapo 39 cent electrical receptacles, installed in series.
These cheap kind have spring loaded "quick insert" connections on the back, instead of proper heavy duty screw terminals on the side.
If the "quick insert" is loose or poor quality, excessive voltage drop will occur across the receptacle, when a high current load is turned on (like your hair dryer or steam iron).
Hopefully (?) the home DID go through code inspections by the city inspector, which would probably have detected grossly illegal or sub-code wiring practices.
*Espanto,I'm not an electrician so maybe someone can double check this off the wall idea. (Guys this is where you come in) Is it possible that in the confusion two circuits got bridged? Basically tied together so they are running off both breakers therefor loading down when over loaded together? Again, I'm out of my field but it was a wild possibility that just jumped into my head. I'm not even sure if this is possible, any help out there?
*I don't think this is such a mystery. I think Tom is right. Probably overloaded circuits, #14 wire, poor connections, cheap receptacles, shoddy workmanship , long runs of wire, etc. I'd just disassemble every receptacle and check for the basics. Replace what you have to and do the job right!
*
Espanto
Overloaded circuits to be sure. In Ontario we routinely wire whole houses with #14 wire, for all plugs and switches. . . I know, I know, Americans seem to favour 20 amp #12 for the same thing, but when the circuits are properly sized, in other words a max of 12 outlets per circuit with a max of 1500 watts continuous per 15 amp circuit, there are no problems. Perhaps the 20 amp circuits lead to more potential overloading???
In such a large house voltage drop
i may
be a problem, but if you can isolate those 2 circuits and divide each of them up by wiring back to the panel for 2 new circuits your dimming problem should go away
i OR
if the bath and laundry are near each other perhaps one new circuit incorporating the two offending receptacles could be rewired fairly easily!!
*I'll say that I would think #14 wire , long runs, maxed out circuits. Obviously the voltage is dropping off at the lighting, but I doubt the receptacles would contribute, unless the lights are wired from a push-in on the back of a receptacle. How many lights are there in these rooms?One other question - how far is the house from the transformer?-Rob
*My guess, and its just a guess, is that the two circuits while on separate hot circuits, share a common neutral along the way.In other words, some clown picked up a neutral in the ajacent room. Try to isolate the plug or light fixture, using 100 ft extension cords back to the main box if you have to, and go from there.
*
Are these problem areas on the end of the house opposite from the breaker box? I'm not an electrician, but my brother-in-law built a 5,000 plus sq ft home. He was advised to put in a sub-panel on the other end of the house. This avoided long runs and voltage drops. Besides, it was cheaper (and easier) to put in the sub-panel than to run all that extra copper.
If you are going to re-wire anyway, do it right an put in a sub-panel on that end of the house.
*
Sounds like a big house, so long wire runs and poor connections can easily cause problems.
Another possability is that two circuits on the same side of the bussbar may be sharing a neutral. That is, for a typical single phase 110/220 volt AC panel, there would be a red and a black coming in as hot, not including the neutral and ground. There is 220 volts between the red and the black, and 110 volts between either and the neutral.
This is how it works: If the loads on the black and red are the same, there is no current on that part of the neutral as I understand. The sine waves cancel each other out. Hence you can use a cable with 3 wires w/ ground to do two circuits. Red, black, white, ground. Should be the equivilent of two cables of 2 wire with ground (black, white, ground) if wired correctly.
However, if somebody was creative enough to break rules and put both the red and black wires on the same "side" of the panel, the neutral would be overloaded. In such a circuit using 3 wires w/ ground, if each the red and the black are carrying say 15 amps (from seperate 110 volt circuits), the white would be trying to carry 15+15=30 amps, which will cause the lights to dim or the motor to slow, and can cause overheating of the wire or connection of course. The circuit breaker only senses the "hot" sides and does not realize the neutral is overloaded. No protection.
I'd check the panels to see if there are any such cables (3w plus grnd), where both legs (red and black) go to the same "side" of the panel. I am using the term side loosely, and am just an architect, and may be using non-standard terminology. The different legs of the circuit often zigzag back and forth from side to side, and half-sized breakers can complicate things, you need to understand your particular panel. Check the diagram that would be on the inside of the panel door.
They could have made the bad set of connections somewhere besides the panels, but I'd try the panel first, as it is the easiest to find.
Hope this helps.
*My guess, and its just a guess, is that the two circuits while on separate hot circuits, share a common neutral along the way.In other words, some clown picked up a neutral in the ajacent room. Try to isolate the plug or light fixture, using 100 ft extension cords back to the main box if you have to, and go from there.
*
Wow! You've all certainly brought up some interesting possibilities! I'll be trying all your ideas immediately.
I'm particularly intrigued by the errant "Neutral" possibility mentioned by Scooter and Gary W. I'm not an electrician either, but if I were to go to the panel, aren't the neutrals all tied off a common bussbar and therefore the same point?
The red and black tied together also seems plausible. Aside from looking at the panel, does it seem logical to go and pull all receptacle covers and light fixtures in the areas of concern to see if there is a black and red wire tied together?
I really appreciate of all your responses..keep em' coming!
Mucho thanks!
*
Espanto:
From your post, I do not think the #1 and #2 problem are related, but occour at different times. I think long wire runs may be contributing, as well as using the push in terminals on outlets without using pigtails. But the biggest factor will probably be the overloaded circuit idea. Whoever designed this house did it to save money. In this day of 1500 watt hair dryers, you need to put each bath receptacle on its own circuit. Do not use this circuit for even the bath lighting, except if the light needs the GFCI protection the outlet provides. A 1500 watt hair dryer will dim lamps due to voltage drop.Also, the laundry or sewing room should also have a dedicated outlet for the iron for the same reason. A lot of people assume lamp dimming is a way of life, others are more sensative to it. I recall when TV's were more sensative to line voltage, and furnace motors would shrink pictures during startup.
The cure for your house will probably be to pull new dedicated circuits to the iron and bathrooms.
Frank
*Espanto,Frank's got this mystery solved...Add circuits or live with it.Short posting for a happy Joe,J
*All the neutrals ARE tied together. And would be in this case also. That's not the problem.The problem is that apparently two hots which are not out of phase with each othere are using the same neutral.If you've ever seen a chart of voltage in an AC circuit, it is a sine wave. Sort of a zig-zag curved line. The voltage goes from zero up to 130 volts or so, and then down to zero, than down to about -130 volts, then up to zero, and repeats this 60 times per second. They average this voltage off some and call it, say 110 volt (RMS) Alternating Current. Or 115 or 120 or whatever.Let's call this graph the "A" leg. Say it represents the heavy black wire coming into the panel. The other hot leg, the "B" leg, is usually marked red. The neutral is the same size or sometimes slightly smaller than either of the hot wires. This is because it normally carries less current than either of the hots, unless someone did something wrong. It carries less load because the other sine wave is offset 1/2 cycle or you could say it is 180 degrees "out of phase". If you add two identical sine waves that are direcly out of phase, you get a straight line, that is, no current. The peaks of one counteract the negative peak or valley of the other.On the other hand, if you put two sine waves that are IN PHASE together, the peaks build on the peaks of the other. That means, even if you have 20 amp breakers, and we use the example of the two 15 amp loads I mentioned earlier, you end up with 30 amps of load on the neutral, and the circuit breaker doesn't know to trip!You don't have to understand the mathmatics of this completely to understand electrical, but it helps explain why electrician's know higher math than carpenters.It is quite possible that the two circuits that have the similar problem, are sharing the same neutral.Wish I had a blackboard...
*
Gary W,
Actually, I can visualize what you are saying just fine without the blackboard since my background is electronics (not electrical).
So let's get back to how I zero in on how to localize the problem...and a cure or should I resort to Frank D's. suggestion and just bring in new circuits?
What'cha think?
*whoa guys-a lot of wild stuff flying around here-neutrals, hots/ phases etc.It is code ok to share a neutral in some cases but I would not do it because of the bad and hazardus stuff that can happen if you get an open neutral. Just because the two side of the power source in the breaker box are out of phase doesn't cancel the current in the neutral! If both circuits share a neutral, both currents flow in the neutral and you can have current flowing both directions at the same time through the same wire.But really the culprit here is voltage drop as suggested earlier and a likely causes would be long run with light gauge wire and or the push in connections on the back of the plugs/switches. And the push in connections ARE eventual fire starters. The push in connections are higher resistance connections which heat up and the metal parts move with the heating/cooling and have teeny tiny arcs/sparcs causing erosion of the connection metal which eventually can fail or if a high load is left on for a long time can cause fire. I would suggest that identifying the problem should be priority to you. If the system has gone years this way that only means you are that much closer to a failure.This reminds me of the aluminum wire problems of the 70's when copper prices went sky high and aluminum was substituted in many houses, some with disasterous results later on because of high resistance connections.Get competetent electrical help, it may not necessarily be an electrician but maybe an electronics wizzard who knows about house wiring. Not all electricians are good at this kind of troubleshooting just like some engineers can design great stuff but couldn't fix the kitchen toaster if their life depended on it.good luck
*
Espanto,
Your problem is exactly what you are observing. The lites that dim and any other item that loses power need to be put on new circuits to cure all. Forget all the complicated posts...You could have these new circuits run and all the drywall patched and painted in the time it's taken here to overly solve your simple problem.
Start pulling wire,
J
*Right Arm, JackIf he'd started at 9:45 a.m. when I posted he could be done by now. . . showered & checked out the new hairdryer circuit and pressed his threads. Are you gonna slap him Jack or should I. . . maybe Joe is closer. LOLb Beware of de-tails, they're usually attached to something furry!P
*If he comes to the b "First Annual 1999 Fall Fine Homebuilder's Breaktime Poster's Get-together Fest," we can all slap him, then we better pour him his next beer!b Looking forward to the festivities,J
*
Gary W,
I can visualize what you are saying just fine without the blackboard since my background is electronics (not electrical).
So let's get back to how I zero in on how to localize the problem...and a cure or should I resort to Frank D's. suggestion and just bring in new circuits?
What'cha think?
*
Espanto, you haven't given a reply to the question: how far from the panel are these problem rooms? Far from being an esoteric delemma, the root cause is variations in line voltage. The potential mechanical causes are: Long runs of 14 gauge wire (over 50 feet), poor quality outlets and/or poorly made-up connections, and overtaxed (overloaded) circuits. Forego the complex wiring diagrams and disertations, though well intentioned; and pull more wire, buy better outlets, and check all connections on those circuits (upgrade).
Too long 'a post Joe?
*Aw rightWill there be any i dwarf tossing???P.
*Definitely!Patrick, I started a topic on this...J
*Jack, the Fall Classic? Hmmm, Sean Messenger said no party until he gets that super-mega Monitor he's lusting after. 'Til then, all the beer and chip money is being escrowed.
*Hey, Jack. Funny, but you posted a thought I have been having. A Poster's Get Together!!! We could stand around and gawk at each other's wives/girlfriends while we swig Guinness on tap and verbally slap each other. Heck, we could even talk about to vent or not to vent.I suggest a beautiful sunny meadow. It's not far from here.
*RichVerbal slapping is for designers, this should be no holds barred,i bring your own dwarf.
*
George,
Sorry for the oversight. Just went out to take a look. THe lower level laundryroom is approximately 60 feet from the panel and the second level bedroom is about 80 feet. Note that both rooms are amidships of the house and that there are rooms further out (40+ more feet approx.) that do not have similar problems. Your next question will probably be whether they used 12 or 14 gauge wire. I'll have a look tomorrow and keep you posted.
Thanks for your suggestions. They make lots of sense!
*George,Sorry for the oversight. Just went out to take a look. The lower level laundryroom is approximately 60 feet from the panel and the second level bedroom is about 80 feet. Note that both rooms are amidships of the house and that there are rooms further out (40+ more feet approx.) that do not have similar problems. I also just checked the "hot iron" receptacle that drags the powered vent fan down when in use and it is a Leviton brand that has facility to push in wires or wrap them around terminals. In this particular instance, the 12 gauge wires are pushed in and not wrapped. Is the concensus that this method of attachment is not a good thing?Thanks for your suggestions. I'm learning lots!
*George,Sorry for the oversight. Just went out to take a look. The lower level laundryroom is approximately 60 feet from the panel and the second level bedroom is about 80 feet. Note that both rooms are amidships of the house and that there are rooms further out (40+ more feet approx.) that do not have similar problems. I also just checked the "hot iron" receptacle that drags the powered vent fan down when in use and it is a Leviton brand that has facility to push in wires or wrap them around terminals. In this particular instance, the 12 gauge wires are pushed in and not wrapped. Is the concensus that this method of attachment is not a good thing?Thanks for your suggestions. I'm learning lots!
*
Espanto, if the wire is fastened to the outlets by means of the screw snugging a internal plate against the wire, they're ok. If held in place by means of a spring tension device, replace with newer "Commercial or SPEC GRADE" outlets. Hope this helps.
*
George,
No such luck. It's the spring loaded type!
I'll check other areas in the morning. Right now I'm anticipating the worst and rummaging through my Rolodex to find the address of the original spec/builder. May have to run over and show him my new 12 gauge Winchester!
*
Call in the lawyer dogs!
*
Espanto -
Did you check. Was there a lot of 14g Romex used?
I toured a million dollar house under construction. Very nice - but it was obvious that not a lot was being spent on wiring. There were 3 floors (or was it 4), a pair of 200A panels and miles of 14g Romex. What was the voltage drop from lower garage panel to top floor back?
Give me the distance and the wattage and such and ElectriCalc 96 will do the VD calcs for you.
Commercial grade outlets were recommended - way to go. Increased wire diameter is another option, but not as cheap and easy. But - the outlets and the lights are on the same circuit?
ToolBear
*Espanto--Look for a bad splice. Or a damaged conductor that creates a high resistance path.Bad splice--maybe a pigtail with the wirenut not properly installed, or a receptacle outlet (duplex outlet) which has been used as a part of the circuit (i.e., used to connect two or three conductors together). Especially the "stab-in" type backwire ROs. A high-Z splice will pass some current, but when you put a high load on it, the voltage goes south. And you get dim city. Suggest you:-- map all the circuits in the house. This will tell you if you've got overloaded circuits;-- isolate and de-energize the problem circuits. Watch out for common neutrals--you think you've cut power and someone turns on a lamp on a circuit sharing a neutral and LO! you've got voltage on the previously dead neutral. Safest to shut off all power to the house;-- get a multimeter and check resistance of each conductor in those circuits, far end to panel. Use the equipment grounding conductor as your test lead, or better, a long extension cord modified with alligator clips at the ends. If you get more than an ohms or three resistence in either the hot or neutral, start opening the legs of the circuit and see if you've got a bad splice (or maybe an almost-cut conductor somewhere from a drywall nail or screw, or similar).You could add another circuit, but that won't address the underlying cause. Voltage drop due to length of run isn't considered an issue in residential unless you get 100' away from the service entrance.It won't be easy or quick. And there are a lot of other mistakes that aren't apparent. I suggest you find a good electrical troubleshooter.
*Espanto, I repeat my original advice. Start with the BASICS. Don't get carried away looking for some other voodoo problem. If you had all of that other stuff wrong with your wiring , your GFCI breakers would be popping all the time. Other than a basic wiring mistake such as overloading circuits or using #14 wiring for your receptacles, there is a 99.9% chance you are going to find your problem right in your receptacle boxes.And by the way, the only logical reason I know of for using #14 wire, is to save $50 on the cost of your house!
*
b Holy Complexities Batman!
b Why not just bring in the dozers and lawyer dogs...
Devices need to be screwed not stuck, buy higher grade if you want ones that will last in heavy use.
b and separate lites from receptacles if you don't like the flickering. (It should have been done this way, but obviously this job was like 80% of all things MONEY BASED BUSINESS!
J
*
Great advice and comments from all of you! Very much appreciated indeed!
It's obvious that many of you are experienced, knowledgable and very aware about the shortcomings of spring tension insert connections on receptacles....yet they're out there all over the place and obviously in use.
So where the hell are the manufacturers (Leviton, where are you?) that should be reading these forums?
*
Espanto,
All receptacles come with screws. Quality workman who don't like nightmare callbacks like yours...
b Use them always.
Jack
*
Great advice and comments from all of you! Very much appreciated indeed!
It's obvious that many of you are experienced, knowledgable and very aware about the shortcomings of spring tension insert connections on receptacles....yet they're out there all over the place and obviously in use.
So where the hell are the manufacturers (Leviton, where are you?) that should be reading these forums?
*
I think I saw one the other day at H.D. that didn't have no screws.
*Send me proof.
*I have found the switch with no screw terminals, I'm looking for the receptacle.
*The computer here is back from a week "on location".There are tricks to proper use of screw terminals, wrapped about 2/3 or so around, clockwise, be careful that copper wire isn't nicked by the stripper such that a crack can develop. Wiring Simplified is a good bookIf you want to check to see if a shared neutral is the problem with the two circuits in question, you can easily check with a VOM.The reason I think it is important to find the cause of the problem and not just replace a couple circuits, is that you can then figure where they made the same mistake, and fix it at each occurance. Otherwise, the house is a mess of undiagnosed problems, patches, and abandoned wire runs.My first residential wiring project started with the black and white wires reversed. I had understood someone wrong. When I learned WHAT was wrong, it was easy to switch all the terminals back. Didn't have to replace everything. (Silver terminal goes to white, dark brass goes to black, switches are another matter)
*
Espanto, et al;
b I tip my hat to all!
The best trouble trouble shooting is to stop & think it through before you put a driver to the first screw.
I do not suspect common neutrals. A shared neutral between hots on common leg will contribute to heating but not voltage drop. The voltage drop on a piece of #12 or #14 wire at 120v (nominal) 60 Hz is almost flat over a 1 to 30 amp sweep.
Voltage drop is the most likely culprit. Loose connections in wire nuts, switches & receptacles is a great place to check. We got into the debate on twisting wire within wirenuts on another post. The more wire contact you have reduces the resistance within the connection. The same works on the spring contact versus screw terminal receptacles, as the spring contact adds resistance,
b ie voltage drop.
The house was probably inspected to the 1987 NEC (if at all). That was the code change that separated bathroom GFCIs from garages & outdoors.
b It did not require separate branch circuits for bathroom GFCIs.
Problem #1 is likely due to voltage drop of distance & common circuit between bath & bedrooms.
Problem #2 is again voltage drop. I suspect mostly the long run & possibly poor receptacles.
Any receptacle that will see heavy usage (vacuum cleaner, etc.) or high current draw (irons,appliances, etc.) should be no less than spec grade. Industrial grade may be the best choice in certain (kitchen) applications.
Start at the load center. If the house was wired by the DIY class, I doubt they used 3 wire (common neutral) circuits. 3 wire circuits are required to have the breaker handles tied. The handle tie is for visual reference only. It does not give you common trip. The safe method is to use 2 pole breakers (common trip) on all 3 wire circuits.
Make sure the breakers are exercised (off then on again) and all wire connections are tight.
Measure the voltage at the mains.
Go to the offending rooms. Plug in a load (hair dryer or iron) and measure the voltage again. If the voltage is below 115 at the loads or more than 5% between the beginning & end..... voltage drop.
You mention 50 - 80 feet. Is this actual run or a chalk line run? Actual wire footage is much higher than the actual distance. I have seen some stupidity runs )mostly on GFCI) that are 300%.
This time I'm tipping my Blue to all you accomplished trouble shooters.
cheers; JE
*
John:
If the voltage drop on a piece of #12 or #14 wire at 120v (nominal) 60 Hz is almost flat over a 1 to 30 amp sweep, then I conceed.
A common neutral would not be the problem.
*John,Thanks for the concise and precise troubleshooting post...I may have to print it out and stick it with my 3m wire trace kit.Thanks again,J
*
John,
Please clarify your statement:
"The voltage drop on a piece of #12 or #14 wire at 120v (nominal) 60 Hz is almost flat over a 1 to 30 amp sweep."
Voltage drop is calculated using Ohm's Law (V=IR) where
R is resistance of wire, I is current and V is drop. This is a linear equation. If current goes up by 30x (i.e. 1A to 30A), voltage drop goes up 30x (i.e. 1V to 30V, an exageration). A common neutral works when the two 'hots' are 180 degrees out of phase (the currents cancel) and the worst case in the neutral is when one hot has no draw. If the 'hots' are in phase the current in the neutral is simpy the sum of both currents in the hots.
Maybe I misunderstood you.. Did you mean that the voltage
drop was "negligible" on a 50-80 foot run in #12/#14 wire?
*Walter;Good questions. You are correct on the 3 wire (common neutral) circuits. They do require hots from opposite legs. I should have stated:i "The voltage drop on a piece of #12 or #14 wire at 120v (nominal) 60 Hz is almost a flat b line (fixed resistance) i over a 1 to 30 amp sweep." The wire is ab fixed value resistor if the supply voltage and frequency remain the same. The wire resistance drops the available voltage at the load. V=I*R is an inverse relationship between voltage & current, when one goes up, the other goes down. I used the 1 to 30 amp sweep as an approximation of 2 - 15 amp circuits on the same leg sharing a neutral. An Electrical foremen told me the same relationship holds true with intelligence & common sense, when one goes up, the other goes down.Cheers; JE
*Voltage drop is a function of resistance and current as you state, with the resistance increasing as distance increases. This usually stays within the suggested 3% for a branch circuit of 100 ft or less, but remember, for a 120V branch circuit you must include the return leg in your calculations, ie, for a 50 ft run of 12/2 or 14/2 on a 120V circuit, you have 100 ft of wire thru which the electricity must run.
*
The setting is a million dollar home built by a spec "homeowner/builder" that apparently used equally inept friends and/or relatives to help with various aspects of the construction phase....including electrical wiring! There are two problem areas in the 6400 square foot house, seperate floors but virtually areas that are directly over each other on two floors.
Problem 1: With the lights on in one upstairs bedroom, the lights "dim" when a hair dryer or similar device are turned on in an adjacent bathroom.
Problem 2: A similar action occurs in the first floor laundry room when overhead lights (fluorescent) and powered vent are on and the homeowner plugs in the steam iron. You can audibly hear the powered vent slow down when the iron is switched on.
Problem 1 & 2 are not on a common breaker. We've had two electricians look at the problem and they seem to dismiss it as not worthy of their time to correct (ho-hum). They may be daunted by the size of the residence and the number of possibities. Using a "plug-in" circuit tester on outlets to check for polarity problems shows everything is fine in these areas. The house has been occupied for six years with no apparent negatives (fires) other than the annoying "dimming". In case it is relevant, ther are GFI's in both these areas also.
Anybody out there care to venture a remedy or some way to narrow the possibilities that could cause these problems?
Much appreciated!