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  • #590885

    3) Any ceiling fixture box can benefit from having three-conductor cable run between it and the switch box. If you ever install a ceiling fan, you can now control the light and fan independently from the wall switches, without needing to rely on a pull-cord. Once again, this is recommended for new construction, not that you should rip open your walls if the wiring is already in place.

    #781411

    Simple yet Brilliant:

    How a three-way-switch works.

    Most of us are familiar with three-way-switches.

    If you have a light that can be turned on or off from two different locations (i.e. a stairway light that can be turned on with one switch at the top of the stairs and turned off with another switch at the bottom and vice versa), you are using three-way switches.

    How do they work?

    Let’s start with the operation of a standard (two-way) switch, which is easy enough to figure out:

    .
    ??? <-switch (in on position)
    Hot ????????????????????????????
    ??? ? <-light bulb (on)
    ?
    Neutral ???????????????????????????

    Electricity flows from the hot wire, thru the switch, into the lightbulb, and out thru the neutral wire.

    If two two-way switches were on the above circuit they’d both need to be in the “on” position for the bulb to be lit.

    This would enable either switch to independently turn the light off.

    …but…

    Neither would be able to independently turn the light on.

    A three-way switch allows both the “on” and the “off” of either switch to operate independently.

    Here’s how:

    .
    ?????
    a? ? ?b
    ? ? ?c
    ?????

    This is a three-way switch, with the switch in the “up” position.

    “a”, “b” and “c” are terminals that wire is attached to via screws.

    With the switch in the “up” position, an electric path exists between terminals “a” and “b”, while “c” isn’t connected to anything.

    .
    ?????
    a? ? ?b
    ? ? ?c
    ?????

    This is a three-way switch, with the switch in the “down” position.

    With the switch in the “down” position, an electric path exists between terminals “a” and “c”, while “b” isn’t connected to anything.

    Now to redo the original diagram with three-way switches:

    .
    ?????s1 ?????s2
    Hot ????a? ? ?b?????????c? ? ?
    ? ? ?c?????????b? ? ?a????????
    ????? ????? ? <-light bulb
    ?
    Neutral ??????????????????????????????????

    1) In the above sketch will the bulb be lit?

    Answer: yes, because

    – The electricity flows into s1-a, out of s1-c, into s2-b, out of s2-a and into the light bulb. The bulb will be lit.

    .
    ?????s1 ?????s2
    Hot ????a? ? ?b?????????c? ? ?
    ? ? ?c?????????b? ? ?a????????
    ????? ????? ? <-light bulb
    ?
    Neutral ??????????????????????????????????

    2) We flipped switch s1. Will the bulb be lit?

    Answer: no, because

    – The electricity flows into s1-a, out of s1-b, into s2-c, but it stops right there since s2-c isn’t connected. The bulb will be unlit.

    .
    ?????s1 ?????s2
    Hot ????a? ? ?b?????????c? ? ?
    ? ? ?c?????????b? ? ?a????????
    ????? ????? ? <-light bulb
    ?
    Neutral ??????????????????????????????????

    3) We flipped both switch s1 and switch s2. Will the bulb be lit?

    Answer: yes, because

    – The electricity flows into s1-a, out of s1-b, into s2-c, out of s2-a and into the light bulb. The bulb will be lit.

    Try this yourself with different switch up / switch down combinations, and you will see that in all cases flipping either switch will reverse the on-off state the bulb is in.

    Sometimes the wiring is done differently (I won’t get into how and why) but the three-way-switch functionality remains the same.

    (lekovod the festival of lights. gong!)

    #781413
    oomis
    Participant

    Oy vavoy, I am SO ONLY calling an electrician for this!!!!

    #781414
    ronrsr
    Member

    Dear O’omis,

    your reaction reminds me of the following joke:

    Q: What’s black and crispy and hangs from chandeliers?

    A: An amateur electrician.

    #781415
    Pashuteh Yid
    Member

    ICOT, how about providing some more info.

    1) Is there a reliable color code for hot vs. neutral, or can it only be ascertained with a meter?

    2) What is major difference between neutral and ground?

    3) Can the electrical box be considered to be grounded? I.e., if no third wire, and there is a need to connect something to a reliable ground, will a connection to the box suffice? For example, when installing a 3-prong outlet where previously only an older 2-prong outlet existed, can one just assume the ground terminal will be grounded by virtue of a connnetion to the box?

    4) If a line is rated at 15 amps, what is highest one can safely use continuously, i.e., for an air conditioner? I have heard up to 80% or 12 amps. Does the number on the circuit breaker always correspond with the actual gauge of the wire used?

    5) In older houses, does the wiring ever fray and present a fire hazard over the years, or can one assume the insulation remains effective even after many years?

    Thanks

    #781416

    Pashuteh Yid-

    Excellent questions, by which I surmise you know at least some of the answers.

    1) Is there a reliable color code for hot vs. neutral, or can it only be ascertained with a meter?

    The reliability of correct color-coding is only as good as the reliability of the person who did the work.

    Standard two-conductor cable should use black for hot, white for neutral.

    Standard three-conductor cable should use the black and red as the hot circuits, white as neutral. The two hots should not be on the same leg of the breaker panel.

    If you need to use the white wire as a hot (for instance switching a dedicated 110 circuit to a 220, or simply running a 220 line) the usual practice is to wrap a band of black electric tape around the insulated end-portion of the white wire to show that it is being used as a hot.

    2) What is major difference between neutral and ground?

    They both end up connecting to the same place (the ground).

    3) Can the electrical box be considered to be grounded? I.e., if no third wire, and there is a need to connect something to a reliable ground, will a connection to the box suffice? For example, when installing a 3-prong outlet where previously only an older 2-prong outlet existed, can one just assume the ground terminal will be grounded by virtue of a connection to the box?

    NEVER assume anything.

    If the box is properly grounded and the outlet is correctly fastened to the box there should be no need to attach a grounding wire to the green ground screw of the outlet.

    4) a) If a line is rated at 15 amps, what is highest one can safely use continuously, i.e., for an air conditioner? I have heard up to 80% or 12 amps.

    80% for continuous load is correct. Breakers and fuses are sometimes designed to allow a brief surge above the maximum designed amperage, for the startup of appliances.

    b) Does the number on the circuit breaker always correspond with the actual gauge of the wire used?

    It always corresponds with the minimum gauge of wire that should be used.

    5) In older houses, does the wiring ever fray and present a fire hazard over the years, or can one assume the insulation remains effective even after many years?

    Since the only other option is rewiring the house, we often by necessity operate under the hope and assumption that existing wiring is OK.

    Here are two of the most common issues with older wiring (assuming it was done properly to begin with):

    a) Old wiring with cloth insulation. The insulation can become very brittle and crumbly over time. This most often presents a problem when you open a switch or fixture box to change something, and the manipulation of the wires causes the insulation to crack off or disintegrate. It’s a royal pain to work with this older wiring.

    b) Aluminum wiring. This was used for a relatively short period of time (about forty years ago). The problem with aluminum is that it expands and contracts differently than materials it was connected to, which can lead to loose connections, which may cause arcing (heat = fire hazard) and shorting.

    As far as I know, copper wire itself remains stable over the years.

    Fraying would result from physical wear, such as an extension cord that is stepped on and pulled.

    A couple of side points:

    Splices should always be twisted in a clockwise direction, so the fastening of a wirenut over the splice is in tightened in the same direction.

    #781417
    oomis
    Participant

    “Dear O’omis,

    your reaction reminds me of the following joke:

    Q: What’s black and crispy and hangs from chandeliers?

    A: An amateur electrician. “

    Oh G-tenyu! LOL!!!! (sick joke)

    #781418

    I really strained my eyes last night

    (No, I don’t need an optician)

    I worked ’til 10 by candle light

    ‘Cause I annoyed my electrician

    😛

    #781419
    Pashuteh Yid
    Member

    “Oy vavoy, I am SO ONLY calling an electrician for this!!!!”

    Oomis, do you mean to say that if your best friend woke you up in the middle of the night and said please help me, I need you to install my new crystal chandelier right away which I just bought in Tiffany’s, because company is coming, you would not rush over at 3 AM? What kind of a friend are you?

    #781420
    Pashuteh Yid
    Member

    ICOT, thanks for all the detailed info. A few more questions for do-it-yourselfers:

    These concern mechanical mounting issues:

    1) If I want to install a reading light on the wall over my bed, where is it safe to put the screws? On one hand I have heard you can damage a beam if you screw into it. On the other hand, I don’t know what the walls are made out of. I assume it is sheetrock. Is that strong enough to hold the light without risk it will fall on my head? So is it better to screw into a beam or to davka avoid beams. In older houses, are the walls generally stronger or not?

    2) Same question regarding installing a light in the ceiling. Should one put into beam, or avoid beam? What if it is a very heavy chandelier like Oomis’s friend wants her to put in? How do you properly support the weight?

    3) Same question if one is installing bookshelf brackets into a wall which may hold heavy books? How do you support the weight?

    Thanks again for your expertise.

    #781421

    Pashuteh Yid-

    1)Reading light-

    d) Lath-and-plaster (commonly found in older houses) is stronger than sheetrock. Also, the odds are good that your screw will go thru a wood piece of lath which will hold a lot better than sheetrock.

    e) Speak to the salesman at the store you buy the reading light re: its weight and support requirements.

    2)Ceiling fixture-

    a) Fixture boxes should always be secured to a beam.

    b) For heavy fixtures or ceiling fans make sure you use a box that is properly secured and can support the weight and vibration. You may want to get a fixture box with expandable brackets so that it can be attached to two beams (especially since attaching a box flush on a beam may cause the box to protrude below the ceiling). In a finished space this can mean some chopping and patching.

    3)Shelves-

    a) Depending on the weight of the shelves and their loads, you can use anchors, toggles or go straight into the studs.

    An electronic stud-finder can be bought cheaply at hardware stores and is quite useful (pretty much a necessity) for projects like these.

    [not sure about the “expertise” part, but it’s a pleasure to help]

    #781423
    Pashuteh Yid
    Member

    ICOT, thanks again. Now how about some lessons on plumbing. After that, please tell us whether a do-it yourselfer can redo a basement. I personally know a doctor that built himself a complete and beautiful office suite in his basement with his own two hands. Carepeting, ultramodern walls and shelves, looked totally professional.

    #781424

    Pashuteh Yid-

    Sounds like you answered your own question.

    Many (possibly most) people are more capable than they think they are.

    The best case scenario for finishing a basement is when you start off with a completely unfinished space, high ceilings, even floor, and no outside water seeping in.

    2) Have completed the floorplan and priced all the materials you plan on using.

    3) Understand the amount of time needed to complete this project.

    4) Understand the amount of effort needed to complete this project.

    6) Have spoken directly to other non-professionals who have done their basements (elements of 3 and 4).

    #781425
    Pashuteh Yid
    Member

    ICOT, another question: The newer energy saving fluorescent bulbs say not to use with dimmers. If you have sliding dimmers in wall, is changing to a switch just a matter of unscrewing wires from dimmer, and putting them right back on a switch (which you can buy for about 2 dollars at Kmart), or is there any difference in the wiring to note?

    Thanks

    #781426

    Pashuteh Yid-

    The wiring is exactly the same.

    #781427
    The Best Bubby
    Participant

    ICOT: You should be a teacher of electrics – You are so patient and B’H knowledgable to help other people with their queries. Tizke le mitzvot!

    Gut Shabbos!

    #781428

    The Best Bubby-

    Thank you for the kind words.

    #781429
    anuran
    Participant

    I can only try,

    Thank you for your clear, accurate, informative advice. It is (literally) a lifesaver.

    We live in a 1908 house. A few years back the original-issue galvanized steel plumbing in the bathroom gave up the ghost. We had a contractor come in to redo the whole thing. I got a call one day “Could you drop by on your lunch hour? We need to talk about a change-order.”

    When I got there he had the electrician. The electrician was deep inside the wall which connects the bathroom and my man-cave/study. They showed me how the outlets and lights in my study were in series with a light light in the closet. The juice only flowed when the light was on. There was no light bulb. The outlets only got power because someone had wedged an old shotgun shell under the switch to create a partial short.

    Just about the first words out of the contractor were “Please, please, please let us fix this. Otherwise, when the house burns down and you die I won’t be able to make any more money off you.”

    I think I broke a few important laws of physics with how fast I signed the change-order….

    #781430

    anuran-

    a) Did you mean the shell was wedged into the fixture? That would sound similar to jamming a penny into a fuse box when a fuse blew (something that supposedly was often done in the old days).

    #781431
    anuran
    Participant

    a) It was wedged behind a key-style switch pushing the contact on the switch onto the contact on the fixture much like the penny in the fuse box.

    b) The end was still sealed. The primer was undented. I don’t know if it would still have fired… how long has it been since they made 16 gauge shells out of cardboard? … but I wasn’t interested in finding out.

    c) Ain’t that the truth 🙂

    I’m really afraid to open the walls…

    I noticed a circular from the IBEW local advertising a seminar on aluminum wiring for home construction. I don’t really trust the stuff, but they claim it’s fine if you do it right. Any thoughts?

    #781432

    anuran-

    I noticed a circular from the IBEW local advertising a seminar on aluminum wiring for home construction. I don’t really trust the stuff, but they claim it’s fine if you do it right. Any thoughts?

    Wikipedia has a pretty good listing on aluminum wiring (old and newer alloy), the issues and problems that can occur with it, and specialized switches and outlets made for it.

    #781433
    Pashuteh Yid
    Member

    ICOT, On your advice, I bought a bunch of switches at KMart to replace the sliding dimmers so I can use them with compact flourescent bulbs and save money. I have wired outlets and swithces before quite a few times. You mentioned that the dimmer is wired exactly like a switch, and should be easy to replace.

    However, I found that the dimmer has its own leads which are hardwired into the unit, and the unit cannot be opened. These leads (black) which incidentally are quite a bit thinner than standard wiring were spaghetti wired via splices into who knows where. There are two dimmers and one switch side by side in one box covered by one plate. I could not trace where all these twist splices were going to. I also seemed to see one group of multiple white wires all twisted together with some copper wire wrapped around all of them seemingly to hold them together.

    The whole thing got me very nervous and I decided not to do it myself, and to find somebody to do it. Why would dimmers have special leads (both on the bottom of the sealed unit, not on the side, like the screws on switches).

    Also, when there are multiple switches for one room (many lights) in one box, is there always a bunch of spaghetti connecting them together, rather than one cable per switch?

    I have an electronics background, and we always solder (to a citcuit board or terminal), rather than wrapping wires and putting caps on them, but do not have much experience with home wiring, which is why I wanted some advice before going in there. How are multiple lights in a room normally handled? I assume they are on one circuit, but I turned off the entire mains before beginning work. I understand they are probably in parallel, but my question is in practice, do you always see these kinds of splices in a box, or are there dedicated wires for each area of the ceiling connected to dedicated switches in the box? Thanks.

    #781434

    Pashuteh Yid-

    First of all, you did exactly the right thing by getting a getting a pro when you found the wiring more complicated than you were comfortable with.

    The explanation below is based on the assumption that you have a “switch before” arrangement – the electricity goes to the switch boxes before it goes to the fixture. It also assumes there are no additional splices in the switch boxes.

    The setup you described as I understand it is three switch boxes ganged together, with each switch controlling one or more fixtures.

    There should be four cables in the box – one hot/neutral going into the box, and three going to the fixtures.

    The switches/fixtures are wired as parallel circuits like so:

    Hot
    
    | | |
    s1 s2 s3
    | | |
    f1 f2 f3
    | | |
    Neutral

    The way this is accomplished is:

    1) Three pigtails (short pieces of wire) are spliced to the hot wire in the switch box. A larger wire nut may be needed for this splice – some large wire nuts look a bit like a deflated balloon. Additionally, care must be taken to ensure all wires in the splice have good connections.

    (Your previous setup probably had the three dimmer leads spliced directly to the hot.)

    [An alternate arrangement that uses jumpers from switch to switch by using the screw terminals and connector holes in back of the switches won’t be discussed here.]

    2) Each pigtail’s other end is connected to a switch’s screw terminal.

    3) The other screw terminal is connected to the black wire of a cable going to a fixture.

    4) The white wires returning from the fixtures are spliced directly to the neutral in the switch box.

    I also seemed to see one group of multiple white wires all twisted together…

    This sounds like “4)”, above.

    …with some copper wire wrapped around all of them seemingly to hold them together.

    I’d have to see this to understand, but it doesn’t sound right.

    Also, when there are multiple switches for one room (many lights) in one box, is there always a bunch of spaghetti connecting them together, rather than one cable per switch?

    It may look that way, because of the need to connect each switch to the one hot coming into the box, as well as the fact that the neutrals from the fixtures end up spliced together.

    How are multiple lights in a room normally handled?

    Generally, as I described above.

    I assume they are on one circuit, but I turned off the main before beginning work.

    They are almost definitely all on one breaker. You can just flip breakers until all the lights you will be working on are off. (It is uncommon but not unheard of to have circuits from more than one breaker in the same box, so you should make sure all the lights go off.)

    I understand they are probably in parallel, but my question is in practice, do you always see these kinds of splices in a box, or are there dedicated wires for each area of the ceiling connected to dedicated switches in the box

    The cable from the switch to the fixture will be dedicated.

    Your arrangement is probably a single two-conductor cable going from each switch to a fixture box. There will probably be a splice in the fixture box to an additional cable if more than one fixture is on the line. (“Probably” and not “definitely” because there can be two separate cables to two separate fixture boxes with the splice after the switch in the switch box.)

    If you have outlets or other fixtures running from your switch boxes it can be more complicated. I omitted possible three-conductor cable arrangements from the explanation above because I don’t think it’s likely you have such a setup (it would be likelier with two switches).

    Overloaded boxes are not uncommon (more connections and cables than code allows), which can certainly give it a “spaghetti” appearance (not that that’s what your box has).

    Switch boxes are sold in differing depths – deeper is always better if you have room for it, to allow more room for wires, splices, and bulkier switches (timers, dimmers).

    #781436

    Pashuteh Yid-

    I see that book is available (used) on Amazon, but you probably should buy something a little more current than a 1980 edition.

    #781437
    happyOOTer
    Participant

    Hey, are you guys licensed?? LOL…

    I have to say I am very impressed that frum yidden know this stuff (not my experience, excpet for the real electrician we had to hire)

    anuran – (picking my jaw up off the floor) If people stop accepting your Shabbos invitations, it’s nothing personal, it’s only out of fear…

    #781438
    Pashuteh Yid
    Member

    ICOT, I just checked, and I have a copy of a Time/Life book called Basic Wiring from 1978, I believe. I passed by a garage sale a while back, and it was like a dollar or so, so I bought it. Very helpful, and probably very similar to the book you mention.

    The theory of electric wiring is very straightforward, however, I don’t have shimush (practical experience). What was bothering me was the use of those caps, which seem like such a poor and unreliable way to connect wires compared to soldering. In electronics, you would never ever wrap wires to make contact. Either you would solder to a terminal, or screw it on to something. If you needed to connect multiple wires like for lights, you would connect short leads to each screw terminal, from light to light in parallel. There is nothing stopping you from screwing multiple wires to a single terminal.

    So for house wiring, I have done the things that involve screws, like outlets and switches, but that assumes the right wires are right there. However, when you have to plan for multiple connections on one line or box, you can’t screw multiple 14 gauge wire onto one screw. I doubt it would fit or hold properly. So from reading the book, I see that the use of these caps is industry standard for everything, and not considered shoddy.

    My questions are when you have to connect multiple wires (3 or more in one splice) what is the best way. You mentioned a wire nut. Please explain what that is in more detail. Also, when working with caps, do you twist the wires first, or simply place them side by side and twist the cap over them. Do they make caps meant for multiple wires together?

    #781439
    Pashuteh Yid
    Member

    BTW, a riddle. ICOT mentioned you need two wires for each light, one for the new electricity, and one to take out the used. Why bother with the second. Why not just supply new electicity to the light with one wire?

    #781440
    haifagirl
    Participant

    Why not just supply new electicity to the light with one wire?

    I know absolutely nothing about electricity. But don’t you need a complete circuit for the electricity to flow? And with only one wire, wouldn’t that be like breaking a connection somewhere in the middle?

    #781441

    Pashuteh Yid-

    …I don’t have shimush (practical experience).

    The most important thing is safety. With experience you will become faster and more proficient at doing the job neatly (i.e. technique for tucking the wire neatly into the box before closing it, running the wire within the breaker panel, etc.)

    However, when you have to plan for multiple connections on one line or box, you can’t screw multiple 14 gauge wire onto one screw. I doubt it would fit or hold properly.

    This is a common no-no. One wire per screw terminal is the rule for switches, outlets, fixtures and breakers.

    I’ve seen this violated by do-it-yourselfers and occasionally contractors.

    It is also a code violation.

    …I see that the use of these caps is industry standard for everything, and not considered shoddy.

    Here’s a little experiment: Splice two or three wires together and screw a wire nut onto the splice (use loose wires – I’m not suggesting you try this with existing house wiring). Try to pull the wire nut off (don’t unscrew it, pull it). You’ll be surprised at how firmly it’s gripping the wires.

    My questions are when you have to connect multiple wires (3 or more in one splice) what is the best way. You mentioned a wire nut. Please explain what that is in more detail. Also, when working with caps, do you twist the wires first, or simply place them side by side and twist the cap over them. Do they make caps meant for multiple wires together?

    “Wire nut” and “cap” are synonymous.

    A splice, whether it’s two wires, three or more, must always have the wires securely twisted together before the wire not is fastened. For a two-wire splice I’ll use a wire stripper (not a knife) to expose about 3/4″ – 1″ of copper and twist them securely together with a lineman’s pliers. More wires in a splice will require longer exposed copper. The splice needs to be long enough to not only be secure from parting, but have a good connection. Using only a wire nut w/o twisting the wires together is asking for trouble; the wires may part or – much worse – overheat due to a poor connection and the resulting resistance. Wire nuts of different sizes are sold – use one appropriate for the gauge of wire you are using (in household wiring 12-guage [20 amp] and 14-guage [15 amp]

    #781442
    Pashuteh Yid
    Member

    Haifagirl, you’re on the right track, but I want to know why you need a complete circuit. Why can’t it just go to the appliance you’re using and stop afterward.

    #781443
    haifagirl
    Participant

    Does AC change directions?

    #781444
    Pashuteh Yid
    Member

    Haifagirl, yes it does. You are getting closer now.

    #781445
    anuran
    Participant

    There’s a knot I learned years ago from a very old electrician for joining wires. It’s a lot like a True Lovers’ Knot. Holds pretty securely and can be put into one of the splicing nuts. Does anyone younger than about 90 still use it?

    #781446
    nnnnnn
    Member

    Haifagirl, Pashuteh Yid,im not sure i know exactly why u cant use one wire to run the appliance but think of it like this, electric current in a wire is kind of like water in a pipe, what if a radiator only had one pipe of hot water going to it and no second pipe for the return, the hot water would not be able to reach the radiator because it has nowhere to go afterward likewise with electricity.

    #781447
    Pashuteh Yid
    Member

    Nnnnn, That is correct. As the first electrons go into the light, they will cause charge to build up, since they have nowhere to go. Charge repels other charges of similar type, so they will prevent any more charge from entering the light, and the current will be zero, so no heat will build up to heat the filament.

    Now for my next questions, is there any heichi timtza (set of circumstances) in which you could light a bulb with only one wire to the bulb? Also, are there any circuits that work despite the fact that there is an insulator breaking up the continuous metal connections.

    #781448
    Pashuteh Yid
    Member

    Due to the great interest in my riddle, and the overwhelming number of responses (zero), here is the answer.

    If the voltage is constant, you can only complete a circuit with a wire for the electrons to leave. But suppose you had a voltage that was steadily increasing (ramping up). Then the incoming electrons have more potential than those already there, and will keep squeezing them and pushing themselves in, even thought there is nowhere for the others to go. One could theoretically light a light this way.

    This is called capacitance, and capacitors are an important circuit component. They are basically a sandwich of two conductors and an insulator in between. Despite the fact that direct current (DC) cannot get through, alternating current (AC) can effectively flow in the circuit. While our homes do use AC, the capacitance of a light ciircuit is too low to create enough current to light the light at 60 Hertz. A much higher frequency, or a bigger capacitance would be needed.

    For example (DO NOT TRY THIS) if one would connect a big metal plate to the dangling end of the light circuit, it would probably light up to some extent, because the plate makes room for more electrons to enter before they feel squished. They can spread out (higher capacitance).

    I believe most touch screens like on a GPS work through capacitance. You can influence a circuit even though your finger is insulated via the glass.

    #781449
    anuran
    Participant

    PY, eventually the dielectric in any capacitor will physically break down, and the current will find somewhere to go. Often in a spectacularly exothermic display.

    #781450
    nnnnnn
    Member

    can u explain watts, amps, and volts

    #781451

    nnnnnn-

    can u explain watts, amps, and volts

    Think of a stream 10 feet wide, in which the water runs at 5 miles per hour.

    Let’s say that every second 100 gallons of water flow past a specific point.

    Increasing the speed of the water to 10 miles per hour would be analogous to increasing the voltage.

    Widenening the stream to 20 feet, while keeping the flow at 5mph would be analogous to increasing the amperage.

    In both cases, we will now have 200 gallons per second flowing past that point.

    Wattage is the total electric power. You derive this number by multiplying amps times volts.

    The amperage needed by a hundred-watt bulb that uses standard U.S. household current can be derived as follows: 110(volts) * ?(amps) = 100(watts). The amperage required is .90909 amps.

    A transformer that raises or lowers voltage is simply changing the voltage and amperage numbers, but the wattage remains the same.

    A couple of unrelated side points:

    a)

    A water-heating system’s radiator will need two pipes; one to bring the hot water and the other to take the water back to the boiler for reheating.

    A steam-heat system will only have one pipe; to bring the hot steam. As the heated steam enters the radiotor, the cold air escapes thru the valve located on the opposite end of the radiator. Once the hot steam reaches the valve, an expanding part in the valve pops up and cuts off the flow of escaping steam. Once the steam cools, it condenses into water, and trickles out of the radiotor thru the same pipe as the steam entered. It is then returned to the boiler for reheating.

    Common problems with steam heat systems are:

    -Valves that don’t cut off when the hot steam hits them. If you see steam escaping from a rediator’s valve, try tapping it gently to see if this will jar the mechanism into closing.

    -Steam leaks along the pipe’s joints.

    (the above two problems can result in leaking steam, dripping water, and the boiler running dry too quickly).

    -A radiator’s air release valve installed on the same side of the radiator as the steam pipe. This causes the valve to close before hot steam has entered the entire radiator, and the room will not heat (or take too long to heat).

    b)

    A/C current doesn’t really run thru a capacitor, but for all practical purposes it’s as if it does. A capacitor prevents more than a certain amount of current from building up on each side of its plates. With DC current, that amount builds up, and then no more can get by. With AC current, since the electrons are basically vibrating back and forth (rather than moving in one direction), nothing builds up on the capacitor’s plates.

    c)

    “Pashuteh Yid”s theory of attaching a large metal plate to a bulb, on the side opposite the hot wire, and seeing the bulb light up slightly is correct (at least with AC; I never tried it with DC). I know this because I once fixed a circuit where the neutral had detatched from the neutral bus bar in the breaker panel, and when a light switch was flipped on for that line, it glowed dimly.

    #781452
    nnnnnn
    Member

    why cant u put a 100 watt bulb in a 60 watt fixture?

    #781453

    If you put a 100 watt bulb in a 60 watt fixture, the fixture can only supply 60 watts, so the extra 40 watts has to come from the free electrons in the surrounding air. This causes a large amount of positively charged air to be localized to one place. If lightning is then present in the area it will be attracted to that area which is, of course, quite an unsafe situation.

    ICOT might have a different explanation though.

    #781454
    nnnnnn
    Member

    so ur saying its only dangerous if there is lightening around?

    #781455

    Well, according to my explanation, that would be correct. But don’t do it until icot gives his point of view.

    #781456
    nnnnnn
    Member

    roger

    #781457

    YW Moderator-80-

    nnnnnn-

    That’s an interesting theory, but it isn’t how it works.

    A 100-watt bulb in a sixty-watt-max fixture will light up, in all likelihood to its full luminescence.

    As with any electrical appliance, it will attempt to draw the full amount of juice it needs to work properly from the circuit it’s hooked up to.

    Here are the hazards of using a bulb whose wattage is higher than what the fixture’s rated for:

    1) The bulb itself burns much hotter than a lower-wattage bulb. This can cause the fixture (or the ceiling, wall, etc. that it’s installed in) to melt, get damaged, or even ignite.

    2) It can cause the insulation of the fixture’s wiring to melt or become brittle, also causing a fire hazard. Since the fixture is damaged, this hazard remains, even after switching to an appropriate bulb.

    3) By drawing more current than the fixture is designed for, it can overload the fixtures wiring, causing it to become hot. The heat can damage the insulation, and if it gets hot enough, start a fire.

    4) One should never overload any extension-cord, appliance, or circuit – it’s dangerous and a fire hazard.

    Here is a complete list of when it’s OK to install a bulb whose wattage is higher than what the fixture is designed for:

    Never.

    I’ve even seen properly installed and used fixtures whose wiring was damaged and/or brittle due to the heat generated by the bulb(s) – kal v’chomer the damage that can be done by overloading.

    Please – don’t even think of overloading a fixture with high-wattage bulb it’s not designed for.

    #781458

    Okay, maybe the lightning was a stretch, but if you walk too close to one of those overwatted fixtures, the positive ions in the surrounding air will pull electrons from your body. And I think we all can agree that electrons are necessary for good health.

    #781459

    YW Moderator-80-

    I’d agree, but it wouldn’t mean much – I’m afraid I have no clue regarding ions, electrons and their effect on a person’s health.

    (note, I didn’t start a thread titled “miscellaneous health tips” – although I do have a theory that one shouldn’t let the potato-kugel level of one’s blood get too low.)

    #781460

    The potato kugel thing, as far as I’m concerned is not a theory but a fact, and I intend to live my life as such.

    As far as the electrons, of course you know their effects on a persons health. Just imagine what would happen if all the electrons left a persons body. You would have nothing left but protons and neutrons. If you know even grade school chemistry you would know that is not compatible with life, let alone health. ergo…

    #781461
    squeak
    Participant

    This may be a pashute question, but I want reassurance. A friend offered to swap out a light fixture and replace it with a ceiling fan. He showed me the wiring and said that he could connect the wires so that the light would be controlled by both the wall switch and the pull chain, but the fan itself would only be controlled by the pull chain (this would be the ideal set up for me because there is only one wall switch).

    This is how he wants to do the connection: The current fixture has two ends of wire, each end having a black and a white wire (and a bare ground wire). The ground wires are connected to each other and the metal part of the fixture. The black wire from one end of wire and the white end from the other end of wire are connected to the fixture’s wires. The other two wires are connected to each other. He said that this is a spliced wire that continues through the ceiling to other rooms and he can connect the fan to the splice, making it live and therefore operated independently of the switch. The light wire and the white return wire he would connect normally to the same black and white wires the old fixture used.

    Does this sound right to the experts here? Should I trust him to do it this way, or should I tell him to just do the basic connection (i.e. fan and light wires connect to black hot wire and both are controlled by the switch).

    Thanks!

    #781462

    Hey, for real-are you guys licensed?

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