If I am wiring a few receptacles on a circuit, it is my understanding that it is advisable to run them in Parrallel, which as I understand it means they are wired in a way such that I am not running my hots into one side of the receptacle, and then back out the other side of the receptacle and back on to complete the circuit.
I was told that this was the best way to do it as any devices that are plugged into other receptacles down the line will not be pulling poweer through the receptacles that come before it on the circuit. This makes sense to me.
So in a typical middle of the run box I will have three black wires under one nut, the black coming in (feed) the hot going to the next receptacle, and a black pigtail which goes to the receptacle in the box.
My assumption is that teh neutrals will be wired in similar fashion, or is this not necessary as they are not carrying 120v. I have one circuit completed and it works fine the way I just described it.
Are there any inherent advantages or disadvantages to doing it this way. Is it okay either way. I would appreciate any feedback on this matter.
Also, I guess while I’m at it I will complete the picture by saying that the grounds are pigtailed to the boxes (metal) and to the receptacles
Thanks
Andrew
Replies
You don't have to pigtail it to have it be wired in "parallel".
There are two screws on each side of the outlet. They are connected by a solid brass plate designed to take the current through. On one side of the outlet there are two brass screws. you connect the black power wire comming in to the outlet under one screw, and the black wire taking power to the next outlet under the other brass screw.
Repeat this procedure with the two white wires on the other side of the outlet where there are two chrome screws.
You are now wired in parallel, and have saved yourself a bundle of time and wire nuts.
I think I got it backwards. Maybe I meant series. Whats the difference? Anyway, wouldn't the way you just described draw all teh current through the receptacle as I pointed out. Thats not what I want to do. So maybe I meant series. I get the terminology confused
the way you did it is appropriate,, the other way is not allowed by the NEC, the device cannot interrupt the circuit when it is removed..specifically the neutral !!...this prevents a very serious condition if the neutral is shared with a hot from the opposite phase that is energized ..and the neutral is opened.
There is a different between wiring DEVICES in series and CONNECTIONS in series.For power wiring all connections are in parallel for proper operation.However, the DEVICES can be wired in either series or parallel.It is poor terminolgy, but when you wire a receptacle so that the power connects to one set of terminals and the downstream to the other it is can be called series wiring. The reason is that the DEVICE is in series and if removed the downstream devices will be dead."Parallel" wiring the devices connects the source, and load wires to pigtails and the pigtails inturn connect to the device. Thus the device can be removed and not affect downstream operation.As to the orginal question the receptacles are rated for the 20 amps FEEDTHROUGH, even for 15 amp receptacles.I think that the "series" connections got a bad name from use of "back stab" connections. When dasy chain receptacles you ended up with 4 backstack connections in SERIES at each receptacle and 4 places for bad connections and high resistance.IMNSHO using quality receptacles and proper screw terminals (or back wiring pressure plates) pigtailing (parallel) is only marginally better than feed through of the receptacles and the extra work might not be worth it. Speically if this is going into older boxes that are 2 small to start with.Also to the orginal question, with one exception there is no difference between the hot and neutral. The voltage has nothing to do with it. It is the current and the current that flows out the hot side flows back through the neutral side.* The one exception is for multi-wire circuits the neutral has to be pigtailed by code. Becuase losing the neutral connection can allow 240 volts on a receptacle.
Thanks Bill.
Loads of good info there.
My experience has always been w/ older homes and smaller boxes, So I have always used good quality outlets, and "feedthrough" wireing.
For my applications, If I need a circuit to remain working w/out a device, I simply install the wire nuts AFTER removing the device.
I realize that there are probably justified applications for both approaches, and appreciate you clearing up the terminology.
Thanks man......
When I was a master electrician in BC, the amended code requirements there said that "all devices have to wired in such a way that removal of one device will not interrupt the circuit.". This meant that all plug outlets HAD to wired with pigtails. In Alberta, you are allowed to use the device as a "feed-thru" for the circuit.
In regard to breaking only the neutral, all devices downstream from the break will then attempt to return current through the ground wire or not work at all (if you're lucky). Most likely scenario... anyone who touches one of those devices runs the risk of being used for the return current; getting a nasty shock, and possibly getting electrocuted. This was one of the reasons for the "pigtailing amendment".
Also; when tying into the main panel, do not put 2 neutrals under 1 screw on the neutral bus. One of my ex-bosses had done this, and didn't tighten the screw properly. The 2 neutrals came loose, and he got 240V going to the fridge. He had to replace a $1500.00 fridge when the motor and compressor went kablooey.
locolobo
Edmonton, Alberta, Canada
"For power wiring all connections are in parallel for proper operation"thank you for your detailed responseI know it's a lot to ask, but could you elaborate on the above comment. It went over my head a little. Thanks,
Andrew
""For power wiring all connections are in parallel for proper operation"thank you for your detailed responseI know it's a lot to ask, but could you elaborate on the above comment. It went over my head a little. "Think back to Christmas tree lights.The mini's the lights are wired in series. That is the hot connects to one lead on the first bulb, the 2nd lead connects to the first lead on the 2nd bulb and so one and one unit the 2nd lead on the last bulb connects to the neutral. If any one bulb is removed all of the lights go out. That is series connections.Parallel connections are like the standard size lights. The hot connects to one side of the bulb and the neutral to the other size and each bulb is connected the same. Removing any bulb does not affect the others.
Yes, I understand the difference between series and parallel but when the boxes are wired with the hot wires together and adding a pigtail to the hot terminal, then doing the same with the neutral and ground wires to their respestive terminals, a failure in one recepticle will not affect the others down the line. If the hot and neutral are "daisey-chained" by wiring to one hot terminal on the first recepticle and out to the next recepticle by attaching the next leg to the seceond terminal on the first recepticle, electricians call it a series connection. I think this might be a case of electricians calling it series or parallel so they can make a distinction in the field. Technically, it's not series, since that would require the hot to go through the first load to reach the second, and then through the second load to get to the third, etc. The Christmas lights (or, should we call them Holiday lights to not offend someone?) are wired in series because of the Clark W. Griswolds of the world, who just can't plug enough lights into one box.
"I cut this piece four times and it's still too short."
The brass plate is usually thinner in the middle for wiring the two separately e.g., one recepticle is switched and the other isn't. This could fuse if the current down the line is too high, causing the first recepticle after the break and everything down the line to go dead. Wiring it this way is usually called series, although it's not the devices that are in series, it's the recepticles. Parallel wiring is where the wires to the box are twisted and a pigtail from each goes to the recepticle. All 3 need to be wired this way and it's easier to stuff everything into the box. Also, if one recepticle goes bad, the rest of the circuit still works.
"I cut this piece four times and it's still too short."
yup....billhartman already educated me on this.
BTW.....for my future jobs....is doing the "true parallel" pigtailed version the way to go, or only in some instances?
I have been told to wire all boxes in parallel. Again, it's so one bad recepticle won't kill most of the circuit. If the outlets are wired series something draws a lot of current down the line, less heat will be generated in the box, too. That little strip between the two oulets would get pretty hot if you have high current devices like space heaters and irons plugged in. The voltage drop down line from the weak link will reduce the life of the devices. too.
"I cut this piece four times and it's still too short."
Thanks,
What do you think about Bills comments about the 20 amp feed through being ok to use in quality receptacles?
I feel he gave a very comprehensive reply, and I got the impression that I could continue to wire the receptacles as I have done in the past.....Devices in parallel, but wired "in series" w/out the pigtails.
Do the pigtails. If you have part of the circuit go dead, you won't need to search for the cause, it's going to be one outlet. If you don't do the pigtails, it'll be every outlet after the problem but it's human nature to look for the problem where it's noticed, whether that's the location or not. An easier way to do it, although more $ is to buy the wire nut with the wire coming out the cap.
"I cut this piece four times and it's still too short."
Bill Hartmann is very articulate, but I always disagree with him on this subject.even though receptacles have a feed-thru rating, the device is a termination not a continuation of a circuit. but not splicing a neutral is a dangerous habit to form , and Bill agreed !! the NEC states that removal of the device shall not interrupt the circuit...... So , pigtail the hot as well
" the NEC states that removal of the device shall not interrupt the circuit...... So , pigtail the hot as well"That is only for multi-wire circuits.The code has no such requirements on either connection for other types of circuits.
True, but some folks may get the idea that what works in one instance will work in others and a bad habit is hard to break .and multiwire probably more common with circuits run in conduit than with clothesline...
Edited 12/20/2005 8:16 am by maddog3
Just to straighten out some terminology:
Both the feed-through and the pig-tail methods are forms of parallel wiring. Series would be connecting the home run hot to the brass screw on the first receptacle. A wire is then connected to the silver screw and the other end goes to the brass screw on the next receptacle. Another wire connects to that receptacle's silver screw and so on down the line until you reach the last one and then a white wire is attached to the silver terminal and then goes back to the panel's neutral bar. That would be series wiring. Think old fashioned giving tree lights. Not a very good idea.
~Peter
Help rebuild Seattle-Tacoma.
You cover the usual objections to daisy-chaining devices so your is the simplest to answer."I have been told to wire all boxes in parallel. Again, it's so one bad recepticle won't kill most of the circuit. If the outlets are wired series something draws a lot of current down the line, less heat will be generated in the box, too. That little strip between the two oulets would get pretty hot if you have high current devices like space heaters and irons plugged in."1)"it's so one bad receptacle won't kill most of the circuit."Question is it the remainder of the circuit going dead really a bad thing. If Ma Kettles iron lung is on the circuit yes. But the question is why would any critical load, or important load like a freezer full of food, not be on a dedicated circuit. Second question is which is more a hazard? A damaged or worn receptacle that demands attention because the remainder of the circuit is out until it is fixed OR a damaged receptacle which is still live but no one knows about because the rest of the circuit is still running fine.2)"That little strip between the two outlets would get pretty hot if you have high current devices like space heaters and irons plugged in."That little strip is not an electrical weak link. It is rated at the full circuit ampacity for which the device is rated for being installed on. All are required, by design, to be able to carry 20A without getting any hotter than either the wire or the device can handle. The only failures of these links I can remember had to do with either a defective receptacle, either made wrong or beat up in storage or a link which contacted the mud ring or wire and shorted out.The wire too gets warm as current increases but as long as it stays below the limit of the insulation to handle it your OK. This is related to the later voltage drop question. While current loading of every link in the circuit chain is a concern focusing on one part while not maintaining perspective won't get you a better system. While it is true when daisy chained the link at each receptacle carries more load as the receptacles stack and get closer to the feed it is also true that the connections at the pigtails are subject to the same progressive loading as you get closer to the panel. As for pigtailed receptacles being easier to stuff into a box this is more a matter of practice and technique. Sorting and dressing the conductors is necessary but once done it is simple and easy to stuff the box with the wires running in a vertical zig-zag pattern.
When I refer to a circuit, I mean a group of recepticles that, under normal circumstances, add up to the breaker capacity. If the outlets are wired in series without pigtails, all loads after the first outlet are supplied by the strip on that outlet. If there are 6 outlets with current draw, the one outlet is feeding all of them. If the outlets are wired in parallel, as they should be, each outlet handles its own load, not the load from other outlets. Actually, a 20A recepticle is not standard for residential, 15A is. "While it is true when daisy chained the link at each receptacle carries more load as the receptacles stack and get closer to the feed it is also true that the connections at the pigtails are subject to the same progressive loading as you get closer to the panel." The pigtails deal with the load only on the outlet connected to the pigtail. They deal with nothing from the other outlets when the outlets are wired in parallel. If the first outlet in a series connection has a load, there will be a voltage drop after the load. The first outlet will not be passing the current to the rest of the outlets as it would in a series connection. Look up Kirchoff's Law and the principles that apply to it. If the outlets are wired in parallel, they have the same voltage going to them. Remember, when a conductor heats up, the resistance increases.
"I cut this piece four times and it's still too short."
"The pigtails deal with the load only on the outlet connected to the pigtail. They deal with nothing from the other outlets when the outlets are wired in parallel. If the first outlet in a series connection has a load, there will be a voltage drop after the load. The first outlet will not be passing the current to the rest of the outlets as it would in a series connection. Look up Kirchoff's Law and the principles that apply to it. If the outlets are wired in parallel, they have the same voltage going to them."You might have 6" of brass strip and 50 ft of copper wire.Based on your reasoning the wiring for each receptacle should go back to the panel and all of them, in one big pigtail, be connected to the breaker."Actually, a 20A recepticle is not standard for residential, 15A is."But 15 amp receptacles are rated for 20 amps feed through.
Go and talk to an electrician.
"I cut this piece four times and it's still too short."
Re: "Go and talk to an electrician."If only we could find an electrician, or two, to talk to ...ROFLMAO.
.......now that's funny right there.....
"Look up Kirchoff's Law and the principles that apply to it. "Actually it has been found that Kirchoff law is ONLY VALID for perfect absorberss." Kirchhoff's Law: Author's Comments
There was a fundamental mistake…namely, the paying of attention solely to the result given by experimental measurements and entirely ignoring the inner realities of the inner processes.Max Planck, The New Science, 1959.Back to KirchhoffKirchhoff's Law of Thermal Radiation was formulated in 1859. It is at the same time the simplest and least understood law in physics today. Kirchhoff's law was describes how an object radiates when placed in thermal equilibrium within the confines of an enclosure.Kirchhoff considered two types of enclosures, isothermal and adiabatic. An isothermal enclosure was typically made from graphite and had perfectly absorbing walls. On the other hand, an adiabatic enclosure was made from highly polished metals and had perfectly reflecting walls. Kirchhoff believed that provided an object was within the confines of either enclosure, that the radiation emitted (or thermal spectrum) was characterized solely by the temperature of the resulting system (object and enclosure). Thermal radiation became independent of the nature of the emitting object.Kirchhoff's Law is central to the development of thermodynamics. Unfortunately, many believe that a temperature can be obtained from a thermal spectrum without knowledge of whether or not the object of interest was in fact in thermal equilibrium with an enclosure. This can lead to serious errors in that the temperatures obtained can be completely invalid.Recently, the experimental justification for Kirchoff's Law has been re-evaluted. It has been discovered that Kirchhoff improperly overextended his law to include the perfect reflector (an adiabatic enclosure). In actuality, Kirchhoff's Law is valid only for the perfect absorber. The consequences are serious. As a result, blackbody radiation becomes critically dependent on the nature of the object in question. A full treatment is provided in the December 2003 issue of "IEEE Transactions on Plasma Science" by Dr. Robitaille. This is a special issue dedicated to Space and the Cosmos. An APS abstract has also been presented on this topic as found above. "http://www.thermalphysics.org/kirchoff/kirchhoffcom1.htmlYou did not post here under another name and claim that electrical tape could be used stop RFI?Bill Hartmann, BEE, MSEE
Didn't Kirchoff also come up with the 'equal voltage' principle in parallel electrical circuits? The reason I brought it up is that I was talking with someone I know who is an electrician and he started talking about it and it's application in electrical wiring. He learned this during his apprenticeship. No, I never posted under another name and I would never say that normal electrical tape stops RFI. I have used copper foil tape with attached copper screen in cars to get rid of audio system noise, though. And mu-metal to minimize EMI, also in cars. What was the application for taping to block RFI? I would like to hear the argument for that one. How about a nice Faraday cage, instead?
"I cut this piece four times and it's still too short."
Mistress El, or something like that ?
I'm still disappointed that you chased him off - those discussions (probably wrong term) were a blast !
I did not chase him/her/it off.All I did was complain about one message where he/she/it kept insulating me and it was deleted.Did see any more post from he/she/it but I did not think that he/she/it would have been band for that, just a warning.But I looked up the thread.Here is where he/she/it first posted.http://forums.prospero.com/n/mb/message.asp?webtag=tp-breaktime&msg=53896.31And I looked at his/hers/it's profile and found this;lesliek3093
Member Since: 3/6/2005
Posts: 16
Last Visit: Dec-16It appears that he/she/it lurking here.
Wow, somehow I missed that earlier thread. It was pretty entertaining, I'll have to try that RF shielding with electrician's tape sometime. I followed the link over to the Bob Vila site, and noticed at one point that person referred to the "2005 edition of the 2002 NEC."
So it seems to me anyway that it is actually more important to pigtail the neutrals than the hots, as apparantly an open neutral is vey bad.
Could you guys please give me a quick lesson on what happens with an open neutral? I have seen it elsewhere but diddn't quite understand it.
I am interested in learning more about teh principals of electricity, could anyone recommend any good books. I have one of those books, I think black and decker makes it, that talks about residential wiring, believe it or not it's pretty handy and I learned a bit from it.
I plan on buying the NEC and just looking through it, you know a little light reading, to see what I get out of it. But I was looking for a good book that would teach me things like resistence, voltage drop, basic and advanced circuits.
Also I want to learn how to use tools and techniques to test and troubleshoot power wiring.
A residential service consists of two HOTS and a Neutral.....240 volts measured between the hots and110 from either to the Neutral......####single circuit of 1 hot and N ...no problem if the Neutral is broken
a multiwire circuit is both hots and a shared neutral...lose the N connection and 240volts WILL be impressed on everything "downstream" of the break ....VCRs, the new Plasma, lamps ...EVERYTHING.... and then you can go buy new stuff , cuz the old stuff is now destroyed........." Also I want to learn how to use tools and techniques to test and troubleshoot power wiring. "that's nice, but dabbling with electricity is something you should leave to someone who does it for a living, not a hobby ,.... although you seem to understand some of the basics , and some here will encourage you,..... I am not one of them .electrician > 34 years but I ain't a carpenter, painter, plumber,...
I respect that stance you have on the issue of "dabelling with electricity"There are some things I am comfortable enough to try. And things I don't touch with a ten foot pole.I am one to admit they have a lot to learn. I more or less just want to have a better understanding of what I am seeing when I walk a jobsite as electrical rough in is taking place.I am also interested in electrical principals. It's not that I wan't to know so I never have to pay for an electrician again, It's that I wan't to know cause I hate NOT knowing.
Edited 12/20/2005 2:55 pm ET by xosder11
Thank You, I think you can buy a book right here, click onSHOP TAUNTON up top.I understand it covers resi wiring......but have not read itmy only advice now .......ALWAYS wear glasses take off jewelry, and when in doubt, shut EVERYTHING off....
If the second 110 isn't in the circuit, how is it going ot affect the circuit that lost its neutral? If the ground coming in with the service goes away, you'll have problems, but if the neutral at a recepticle goes out, you lose the return path to the panel and the circuit goes dead.
"I cut this piece four times and it's still too short."
...didn't I type that? a single 110v line is no problem if the neutral opens up ...it just goed dead,unless there is another problem
Probably did, when I read it it seemed to say that in a 120V circuit it goes to 240 when the neutral goes away.
"I cut this piece four times and it's still too short."
####single circuit of 1 hot and N ...no problem if the Neutral is brokena multiwire circuit is both hots and a shared neutral...
As in a 240 for clothes dryer, or stove etc?
lose the N connection and 240volts WILL be impressed on everything "downstream" of the break ....VCRs, the new Plasma, lamps ...EVERYTHING.... and then you can go buy new stuff , cuz the old stuff is now destroyed......
If I have this straight, and we are talking about 240 v lines, how many 240's get extended to other 120v outlets etc in a residence? All my 240's are terminated at the appliance, one each for dryer, stove, and well pump.
...A multiwire circuit, is two hots feeding 110v appliances or receptacles....ususally this happens where
conduit has been run, and not NM , very few pipe runs will contain only one circuit.usually rooms with high usage get more than one circuit and the easiest and cheapest method is to pull three wires and alternate the circuits throughout that area...lose the neutral and anything that is running is fried . The easiest way to prevent that, is to pigtail the connections. 240v appliances are not affected , sorry for the confusion.....
> lose the N connection and 240volts WILL be impressed on everything "downstream" of the break ....
Not exactly. What you end up with downstream is a voltage divider circuit, one side goes higher than 120 V, the other lower.
Suppose we have a three wire 120/240 circuit, and out at the far end there are two light bulbs. Between leg "A" and neutral, we have a 100 Watt bulb. Between leg "B" and neutral, we have a 40 Watt bulb. Power (Watts) equals Volts times Amps, so the 100 Watt bulb is drawing 0.833 A, the 40 Watt draws 0.333 A.
Consider what happens during the half cycle when "A" is positive. 0.833 Amp flows thru the leg "A" wire and the 100 Watt bulb. 0.333 Amp of that current continues thru the 40 Watt bulb and the leg "B" wire. The difference, 0.500 Amp, returns through the neutral wire.
Now what happens if the neutral gets broken? There's no path for the difference current, both bulbs must carry the same current. That current will be determined by the total resistance of the two lamps in series, and will determine how they divide up the voltage.
For the sake of simplification, for now let's assume that the resistances of the filaments remain constant in spite of the Voltage and current changes. Not true, but OK for this discussion.
Ohm's law, Voltage equals current times resistance. The 100 Watt bulb has a resistance of 120/0.833 = 144 Ohms. The 40 Watt's resistance is 360 Ohms. That adds up to 504 Ohms for the two in series, across the 240 Volts. The current thru them therefore is 240/504 = 0.476 Amp.
Now what happens to the bulbs? The 100, by Ohm's law, gets 0.476 x 144 = 68.6 Volts. The 40 gets 0.476 x 360 = 171.4 Volts. (Note that 68.6 + 171.4 = 240). That's probably enough to blow the 40 Watt bulb real quick, opening the circuit, and everything goes dark.
With real light bulbs, the filament resistance goes up as temperature goes up. For instance, a 100 Watt at room temperature has a resistance of about 10 Ohms, not 144. So, really, the voltage difference is even bigger than under our simplification.
OK, so much for theory. Now let's send somebody to open up a box at Kirckhoff's house and see if he pigtailed his receptacles. ;-)
-- J.S.
John,I started to read ......and then,I don't have the veracity to post long explanations like yourselfI think in the context of this post, it is sufficient to say that real damage can occur and that the incoming voltage is now trying to get through whatever is "on" I appreciate the refresher
Bottom line, in a loss of neutral, the leg with the lighter load gets fried.
Expensive electronics, even when they're "off", often still draw a fraction of a Watt to just a few Watts. Cheap light bulbs draw a lot more than that. So, as Murphy would have it, in real-world loss of neutral accidents, it's often the expensive stuff that gets zapped.
-- J.S.
.....couldn't agree more, did not intend to be rude earlier....I also found this example of a bad connection overheating
Thank you for carefully explaining how the overvoltage occurs during a disconnection of the neutral, John. Until I drew a sketch of your scenario while reading your post, I didn't understand where the current path was when the neutral was disconnected.
I like to run 3-wire and have receptacles alternate circuits in a run. I like to know that in any room I can plug in my shop vac into one receptacle and my circular saw into another and not worry about tripping a breaker. Except in the kitchen where it's required, I don't split every receptacle.
Personally, I've never had a problem with a poor connection at a receptacle terminal but I've frequently seen problems with bad connections where multiple wires are jammed into a wire nut. So using a pigtail rather than the receptacle screw terminals to make the feed-through connection seems OK to me in theory but not in practice. The potential to fry the devices downstream of a neutral splice remains.
In the case of receptacles run with 3-wire: if you pigtail both the neutral and the hot to the receptacle AND splice the unused hot, six wires and three wire nuts exceeds the permitted maximum box fill for a standard 2.5" deep box, right? That means 3" deep boxes for every receptacle. I guess you could pigtail the neutral alone and just get by, but it wouldn't be pretty. Maybe it's a good idea to have that extra box room anyway, so perhaps it's not a big deal. But given the potential for problems with a disconnected neutral, the fact that 3 wire costs virtually double the price of two wire, the cost of the 3" deep boxes etc., maybe it's better to just run alternating strands of two-wire and be done with it.
"Except in the kitchen where it's required, I don't split every receptacle. "BTW, that is not an NEC requirement, just Canadian.In fact the way that they treat GFCI's, kitchens, and 15/20 amp receptacles are very different from the NEC requirements.
Second question is which is more a hazard? A damaged or worn receptacle that demands attention because the remainder of the circuit is out until it is fixed OR a damaged receptacle which is still live but no one knows about because the rest of the circuit is still running fine.
Wow......can o worms here.
I share the same thought. For the record, I only do elec on my own houses, or helping friends, and even then, it is more of a "replace" than add new stuff. Most of what I know I learned from an old "fuss fart" that did everything "the right way" or not at all, and he never did "pig tails" for common 15 amp household circuits.
I still do not see a viable arguement for adding pigtails to every outlet in a home. I have NEVER run across one yet, and last year I replaced about 100 outlets in various places. Not being stubborn here, just not seeing a clear reason to "go the long route".
Based on High School physics (a looooooong time ago) all recepticels (even w/out pigtails) ARE wired in PARALLEL, but can still fail and interupt a circuit (as if in SERIES). Incedentially, if the strip on an outlet "fails" only 1/2 of that outlet, and the rest of the "downstream" outlets will be affected, not the ones before the bad one, correct?
Right- 1/2 of the recepticle and all others downstream. I replaced mine in my house and just wired them the way they were. The boxes in my house are too small to add pigtails. When my garage was wired, the electrician wired them with pigtails and the inspector asked about it. I asked him to clarify and he axplained the difference.In new construction with larger boxes, I would definitely wire with the pigtails.
"I cut this piece four times and it's still too short."
the electrician wired them with pigtails and the inspector asked about it
Why did he question it?
Not a common practice to him?
Just wondering.
He didn't question pigtails being used, he asked IF they were used because he wants them wired that way.
"I cut this piece four times and it's still too short."
gottit, thanx
Re: ..."all recepticels (even w/out pigtails) ARE wired in PARALLEL, but can still fail and interupt a circuit (as if in SERIES). Incedentially, if the strip on an outlet "fails" only 1/2 of that outlet, and the rest of the "downstream" outlets will be affected, not the ones before the bad one, correct?"Your not the only one who is confused or unsure of what is going on in these devices and how they are applied. I run into electricians, many who are quite good at what they do, who have limited understanding of the intricacies involved. Some of them with the loudest voices are down to mouthing the same generalities they most hear from people with no more understanding of the situation than themselves. Most of the generalities are accretions of repetitions and lore around a kernel of truth but then often misapplied. Too often I hear platitudes such as: 'It's better to pigtail' or 'code requires it' or 'only hacks don't pigtail' being bandied about. Rarely does the explanation get any deeper than 'everyone knows that' or 'because' if they are asked why they make the claim. More than once I have had otherwise knowledgeable electricians cite article 300.13(B) while forgetting that it only applies to multiwire branch circuits. Back to the issue at hand.Receptacles that are daisy chained, I use the term because it summons a mental picture for most people which is actually fairly accurate without summoning up unfounded conclusions, are, as a complete unit, both in series and parallel. If the receptacle is pigtailed off the line so there are only three conductors making up to the receptacle then the receptacle is in parallel to other receptacles. The receptacle could be removed and the other receptacles would operate just fine.If the receptacle is hooked up with five connections the links between the paired screws, brass colored on one side and silver colored on the other, are in series. If removed the links were removed the loads down the line stop working. That said the rest of the receptacle, the part where you stuff the plug into, is still in parallel. So to answer your question:
..."if the strip the on an outlet "fails" only 1/2 of that outlet, and the rest of the "downstream" outlets will be affected, not the ones before the bad one, correct?"If by "strip" you mean the small link between terminal screws
You are correct.In the case of a pigtailed receptacle the connectors that make up the three way connection are as vulnerable as links on the receptacle itself. Possibly more vulnerable as the link typically has no insulation on it, depending on air space for insulation, while a wirenut has a plastic cap which can, and do, melt when overloaded. In both cases there are conductors in proximity with vulnerable plastic insulation protecting it from shorting out. Six one half-dozen the other.I don't begrudge any electrician, assuming they have looked into the situation and truly understand it, an opportunity to make the call as to which method they use. Pigtailed receptacles or daisy chained. Pigtailing is, in fact, vital for the neutral connections on a multiwire branch circuit. A situation where more than one hot feed is sharing a neutral connection. As a separate consideration I don't think multiwire branch circuits are appropriate for residential settings simply because it doesn't save much in labor or material costs while it increases the risk of a fault. I don't particularly like any installation where a single fault can cause equipment damage severe enough to cause a fire. Some are unavoidable but why add one more if you don't have to.My preference for daisy chained residential receptacles is both personal and based on careful consideration of the facts and experience available to me. Each method has strengths and weaknesses. I think I have chosen wisely based on giving safety and economy pride of place. One of the few situations where safety, in the sense many problems will trumpet their existence, and economy, pigtailing involves a few more steps, fall on the same side. That is not to say other trained electricians, assuming they really understand what they are doing and why, in light of probable failure modes over time and tradeoffs made, cannot draw, in good conscience, their own conclusions.
My personal preference is to pigtail, provided I'm doing all the other oddball things that I prefer. Like soldered splices, big 4 11/16" steel boxes, 3/4" EMT, and compression fittings..... Hard on the outside, easy on the inside seems to be my style. ;-)
-- J.S.
Now you're talkin
Thank you for a concise, and well thought out response.
If by "strip" you mean the small link between terminal screws You are correct.
Zactly
Receptacles that are daisy chained...... are, as a complete unit, both in series and parallel.
I am not an electrician, so I may well be wrong (I have been before), and I am definitely not trying to antagonize here, just pondering.........I still think that regardless of being pigtailed, or daisy chained, all residential receptacles are wired in parallel. Since standard duplex residential receptacles have no internal bridge between the hot and neutral slots, they, by themselves would NEVER work if wired in true series. There would be no way for the current to continue.
If they were wired in series (thinking Christmas lights here, let the light "socket" be the outlet, and the bulb be the appliance that bridges the gap in the "hot" wire so as to feed the next one), how would outlet # 2 get current if no appliance was PLUGGED INTO outlet #1 one? Remember, in series only the last outlet would have the "home run" neutral connected to it, not the others. Consequently, none of the other outlets would work either.
A true series connection would require that appliances of some sort be plugged into all of the outlets at all times for the ANY PART of the circuit to work. The fact that the circuit can still work w/out anything plugged in verifies that it is indeed a parallel wired circuit. It is true that removing an outlet will stop the flow of current to all the others, but that, in of itself, does not qualify it as a "series" circuit. The outlet would simply be functioning no differently than a switch (or cutting the wires) in the parallel circuit.
Does this quirky "logic" make sense?
I could be wrong here, cause most of this of new to me, but wasn't Bill trying to clear the air on that issue of terminology when he wrote:"There is a different between wiring DEVICES in series and CONNECTIONS in series.For power wiring all connections are in parallel for proper operation.However, the DEVICES can be wired in either series or parallel.It is poor terminolgy, but when you wire a receptacle so that the power connects to one set of terminals and the downstream to the other it is can be called series wiring. The reason is that the DEVICE is in series and if removed the downstream devices will be dead."Parallel" wiring the devices connects the source, and load wires to pigtails and the pigtails inturn connect to the device. Thus the device can be removed and not affect downstream operation"
Edited 12/21/2005 10:41 am ET by xosder11
That's what I thought after reading Bill's post too.
Though, like I said, the term "devices in series" appears to be a loose definition, since they are, in fact, actually wired in parallel. I suppose this helps to differentiate connection types on the site, so I can see where it would be useful.
I guess the general concession on the "pigtail vs not", is that both are ok in a residential application, but pigtails are necessary for multi-wired circuits.
The way you define series and parallel is the same way I think of it, and the same way they're used in electronics -- desigining amplifiers and such.
In series, elements having two terminals are connected in such a way that the same current flows through all of them. Hook one of them up to the B+ buss or whatever, hook the next one to the remaining terminal of the first, the third one to the remaining terminal of the second, etc. Finally, hook the last one's last terminal to ground.
In parallel, elements having two terminals all have one terminal connected to one buss, and the other to another buss. So, f'rinstance, they all have one terminal connected to B+ and the other to ground. In parallel, they all get exactly the same Voltage.
Things that we plug or screw into our household power systems are all always in parallel. You could, for fun, put a pair of incandescent bulbs in series. They'd be dim, but it does no harm.
To use the term "series" for feeding thru a receptacle may make sense to people who never see the term used in the more common and standard way. But it'll be a source of confusion if they encounter it in any other context. Clearly, it's been a source of confusion here. I'd suggest calling it "feed through" or "pass through" or some such thing. Those are the terms used on audio and video equipment when they give you paralleled connectors on the back, like BNC's, RCA's or XLR's.
-- J.S.
No help, but the way you describe is the way I've always done it...now I'm curious.
4lorn1, what say you?
PJ
Everything will be okay in the end. If it's not okay, it's not the end.
As several other responders have already mentioned, I prefer to pigtail the neutrals and the hots and feed the receptacle from the pigtails. However, whether or not you can take this approach is dependant on the size of the boxes.
For instance, I had to replace a room full of receptacles today in an older home. The old receptacles had been "backstabbed" into cheap receptacles and after years of use these receptacles had poor connections which allowed plugs to fall out of the receptacles or to have intermittent connections. Not only were the plug sockets worn, but also some of the backstab connections were worn which ultimately caused part of the room to "lose power". I would have preferred to pigtail the leads in the old boxes and to feed my new receptacles from the pigtailed leads, but the old boxes were too small to allow room for the wirenuts you would need for the pigtails. What I did use was specification grade receptacles with compression plate back connection terminals. This allowed me to make good solid connections to the existing wires which were very short and still fit inside the old small 14 cu boxes.
Back connections made with receptacles using the pressure plate style of terminals are quite secure both mechanically and electrically, because the entire stripped end of the wire is compressed between two metal plates. Back connections to the cheap receptacles with "backstab" style terminals should NEVER be used since these style of connectors rely on the knife edge of a thin strip of copper touching one point of the stripped lead. Old backstab connections frequently are either loose or so corroded that they make a poor connection. If you have the cheaper receptacles with these backstab terminals, only use their side wiring terminals.
Also anytime you are replacing receptacles in old or new metal boxes particularly small ones, wrap a few layers of electrical tape around the sides of the receptacles to cover the terminal screws before you push the receptacle back into the boxes. The tape makes sure the receptacle won't accidentally short against the metal box if it ever becomes loose.