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Can I wire sockets with 18gauge wire for 40watt bulbs?

fadingathedgesfadingathedges Registered User regular
edited May 2011 in Help / Advice Forum
I have two light fixtures that I am rewiring the sockets on - one four socket fixture and one five socket fixture. I only use and intend to continue using 40watt bulbs. I believe each is wired with a basic 110 jigawatt line. Is the 18 gauge wire I bought gonna do me right? The 16 was much fatter and I didn't like it.

Bonus point question: Can one still buy the rope-style wires, without the asbestos of yore? I'm picturing a modern wire with an aesthetic cord casing - it seems like someone should have done this.



e~ I don't know anything else about my circuit box except that the house is old as balls and probably was at least partially rewired several times.

Post edited by fadingathedges on

Comments

  • bowenbowen Registered User regular
    edited May 2011
    No.

    Looks like 12 is the standard for sockets, 14 for lights, and 18 for low voltage lights.

    http://electrical.about.com/od/wiringcircuitry/a/electwiresizes.htm

  • fadingathedgesfadingathedges Registered User regular
    edited May 2011
    Let's negotiate until you tell me what I want to hear 8-)


    Seriously though, Google results are telling me different things everywhere I look. Do you happen to have experience with this kind of thing?

    What classifies as a low-voltage light? My lamps run 60watt bulbs.

  • SpudgeSpudge Registered User
    edited May 2011
    Low voltage lighting is decorative LED type lighting.

    Old house, you're probably not going to live in it for the rest of your life, the next owners may use 60w (or larger) in the receptacle, etc etc etc make the lighting up to code and just use the 14 AWG

    Better safe than on fire

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  • bowenbowen Registered User regular
    edited May 2011
    Everything I've found low power lighting refers to things below 15 watts. So... nothing other than LED like spudge said. And there's a distance limit of 25 feet from the source, though I can't verify that with a good source. It's in the wall though, why do you care?

  • matt has a problemmatt has a problem Six pack on a dick Registered User regular
    edited May 2011
    No. It's not negotiable. It's a fire hazard and not to code. It is extremely important that you do it correctly, or don't do it. Electrical wiring is not a place you cut corners.

    Low-voltage usually refers to lighting that runs off a DC supply, 12 or 24 volt. Any standard incandescent or fluorescent bulb you use is going to be 120 volts, regardless of the wattage.

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  • MushiwulfMushiwulf Registered User regular
    edited May 2011
    You are rewiring something like a chandelier? And this is the wire from each individual socket and then up the chain to the box? (Or, if a table lamp, out the base and into a cord cap that plugs into the wall?) What size wire was on there before?

  • ThomamelasThomamelas Bro!Registered User regular
    edited May 2011
    No. It's not negotiable. It's a fire hazard and not to code. It is extremely important that you do it correctly, or don't do it. Electrical wiring is not a place you cut corners.

    Low-voltage usually refers to lighting that runs off a DC supply, 12 or 24 volt. Any standard incandescent or fluorescent bulb you use is going to be 120 volts, regardless of the wattage.

    Low-voltage wiring is usually for telecomm, networking, fire, burg, video and access control systems. Electrical sockets, and residential lighting generally doesn't fall into that category. As to why 18 gauge wire isn't a good idea:

    18 gauge wire is rated for about 10 A. What you're proposing will be less then 10 A so on the surface it seems like it should work. Except that the circuit breaker for most lights is going to be rated for 15 A. Meaning it's not going to trip until it hits that point. Which is 5 A over what the wiring itself will deal with. If you're around 12 to 14 A for an extended period of time then there is a chance it will catch fire. This is generally seen as a bad thing. This is why the electrical code sets out very narrow guidelines about what wires you use for what circuit breakers and what circuit breakers get used for what situations. Now you may say "Well I'm never going to go above 40 watts, so fuck it." which is the exactly wrong attitude. If the home passes into other hands, they are unlikely to be aware you cut that corner.

    So it make it brief, it's a fire hazard. Don't do it. The code exists for a reason and the code isn't written by idiots. Follow it.

  • fadingathedgesfadingathedges Registered User regular
    edited May 2011
    Mushiwulf wrote: »
    You are rewiring something like a chandelier? And this is the wire from each individual socket and then up the chain to the box? (Or, if a table lamp, out the base and into a cord cap that plugs into the wall?) What size wire was on there before?

    It's like chandeliers, the wires with the juice poke out of the ceiling when they are taken down. I am wiring 4 and 5 separate sockets on two chandeliers. The existing wire is ancient brittle stuff with rope casing - somewhat like the stuff shown here but very very old:

    PV2BNSTRBUT_main.jpg


    e~ The current wires are very small, I can't tell if they were 16 or 18 gauge inside the casing because they are pretty frayed. The guy who was supposed to be doing this job said that they were only supposed to run 40watt bulbs, and the previous tenant was using 60's in the operating sockets.

  • MushiwulfMushiwulf Registered User regular
    edited May 2011
    18 gauge is fine for that. I haven't seen material insulation (like your picture) at the hardware store, just different colors of thermoplastic (brown, black, a see through gold, maybe white). You may be able to get other insulation types at a specialty store.

  • fadingathedgesfadingathedges Registered User regular
    edited May 2011
    What about the fires? Does the fact that I am splitting the feed into 4 and 5 lines make it okay?

  • MushiwulfMushiwulf Registered User regular
    edited May 2011
    You are wiring a lamp with, at most 5 sockets. The wire is rated for 10 amps. That is over 1000 watts. Unless you think it is likely someone will put 200 watt bulbs in those sockets, you should be fine.

  • MetalbourneMetalbourne Tube's Favorite Registered User regular
    edited May 2011
    Thomamelas wrote: »
    No. It's not negotiable. It's a fire hazard and not to code. It is extremely important that you do it correctly, or don't do it. Electrical wiring is not a place you cut corners.

    Low-voltage usually refers to lighting that runs off a DC supply, 12 or 24 volt. Any standard incandescent or fluorescent bulb you use is going to be 120 volts, regardless of the wattage.

    Low-voltage wiring is usually for telecomm, networking, fire, burg, video and access control systems. Electrical sockets, and residential lighting generally doesn't fall into that category. As to why 18 gauge wire isn't a good idea:

    18 gauge wire is rated for about 10 A. What you're proposing will be less then 10 A so on the surface it seems like it should work. Except that the circuit breaker for most lights is going to be rated for 15 A. Meaning it's not going to trip until it hits that point. Which is 5 A over what the wiring itself will deal with. If you're around 12 to 14 A for an extended period of time then there is a chance it will catch fire. This is generally seen as a bad thing. This is why the electrical code sets out very narrow guidelines about what wires you use for what circuit breakers and what circuit breakers get used for what situations. Now you may say "Well I'm never going to go above 40 watts, so fuck it." which is the exactly wrong attitude. If the home passes into other hands, they are unlikely to be aware you cut that corner.

    So it make it brief, it's a fire hazard. Don't do it. The code exists for a reason and the code isn't written by idiots. Follow it.

    I'm not an electrician.

    But I am an engineer. Listen to this guy. You want to design a system so that the weakest link is what is meant to fail in the case of an accident. In this case, you'd want the circuit breaker to fail before the wire does.

  • MushiwulfMushiwulf Registered User regular
    edited May 2011
    What about the fires? Does the fact that I am splitting the feed into 4 and 5 lines make it okay?


    If you are running each socket with its own set of wires to a central point and then joining them to one wire that runs up the chain to the ceiling, your weak point is the wire running up the chain. It will be carrying the load from all 5 (or 4) sockets. If you want to prepare for the worst case (that someone will try to run 200+ watt bulbs in every socket), you could size that final wire to the breaker (14g for a 15 amp circuit and 12g for a 20 amp). But generally, lamps are wired with smaller wire internally all the time.

  • fadingathedgesfadingathedges Registered User regular
    edited May 2011
    Thanks everyone, I think I have enough info to figure out what to do. I'll try not to burn anything down.

  • fadingathedgesfadingathedges Registered User regular
    edited May 2011
    Actually - another question.
    Mushiwulf wrote: »
    What about the fires? Does the fact that I am splitting the feed into 4 and 5 lines make it okay?


    If you are running each socket with its own set of wires to a central point and then joining them to one wire that runs up the chain to the ceiling, your weak point is the wire running up the chain. It will be carrying the load from all 5 (or 4) sockets. If you want to prepare for the worst case (that someone will try to run 200+ watt bulbs in every socket), you could size that final wire to the breaker (14g for a 15 amp circuit and 12g for a 20 amp). But generally, lamps are wired with smaller wire internally all the time.

    I talked to my electrical engineer dad and he seemed to think that this was the best plan for my situation. His primary safety concerns were:

    1) Don't shock yourself.

    2) The 'workbox' in the ceiling which structurally supports the fixture and feeds down the wires is sturdy but old - the wires have the same cloth material casing as the ones I'm replacing on the fixtures (though they are thicker and in much better shape). Point is - probably not up to code. I am not capable or willing to address this, so I'm going to pass that on to my landlord and let him worry about it.

    3) The act of joining five wires into one larger wire which I run to the ceiling probably requires a specific technique to do properly.

    How to do?

    Is there a widget that makes this safe and easy? Is there a picture and a list of Do's and Dont's that I can learn from? How many beers should I have first? Googling for it hasn't helped, and I'd prefer a "this is correct" from someone with some experience before I trust a picture.

    Thanks again PA


    e~ Man at Lowe's says "just twist them all together in a wire nut".

  • MushiwulfMushiwulf Registered User regular
    edited May 2011
    Wire nut is correct, just make sure it is sized correctly. They have a sizing guide on the box/bag of wire nuts. I think what you are looking for is the Ideal brand, 452 (Red) WingNut. It will hold 2 to 6 #18 wires.

  • bowenbowen Registered User regular
    edited May 2011
    Yeah probably just a wire nut. But it depends where you're joining them. If it's in a wall or the ceiling you'll probably want a small junction box as well. If it's just at the fixture, a wire nut is fine.

  • FiggyFiggy Registered User regular
    edited May 2011
    bowen wrote: »
    Yeah probably just a wire nut. But it depends where you're joining them. If it's in a wall or the ceiling you'll probably want a small junction box as well. If it's just at the fixture, a wire nut is fine.

    Well, if the wire nut is somewhere in the wall, a junction box isn't "you'll probably want," it's code. It also has to be accessible.

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  • fadingathedgesfadingathedges Registered User regular
    edited May 2011
    There is a pair of wire nuts dangling from the ceiling out of the existing box, but I'm talking about an in-fixture nut that brings all my sockets together before running to the ceiling.

  • bowenbowen Registered User regular
    edited May 2011
    Figgy wrote: »
    bowen wrote: »
    Yeah probably just a wire nut. But it depends where you're joining them. If it's in a wall or the ceiling you'll probably want a small junction box as well. If it's just at the fixture, a wire nut is fine.

    Well, if the wire nut is somewhere in the wall, a junction box isn't "you'll probably want," it's code. It also has to be accessible.

    Yeah that's what I figured, I am obviously not a contractor so I couldn't say for certain.

    If he sells his house and someone finds out that it's not up to code he'll probably end up on the hook for the entire house being gutted and redone. Which is fun.

    But yeah, junction box if it's not at the fixture. You'll likely still need wire nuts, and the red one is for 3+ wires, so go with what the other poster said. All in all it's like $15, it's worth it to not have to pay $house.

  • Iceman.USAFIceman.USAF Captain East CoastRegistered User regular
    edited May 2011
    I can't believe nobody has said this yet, but consult the NEC (National Electric Code). It's not the easiest thing to read though, nor is it cheap, but you should be able to get your hands on a copy from a library or other such resource pretty easily.

    And before anyone says it, yes I am an actual engineer. Not electrical, but smart enough to know it!



  • FiggyFiggy Registered User regular
    edited May 2011
    I am not capable or willing to address this, so I'm going to pass that on to my landlord and let him worry about it.

    Wait a second. Landlord?

    Does he know that you're rewiring part of his property without a licensed electrician? Some landlords freak out when you hang up a picture, so I'd be shocked if this guy gave you the go-ahead.

    If you do this without his say so, and something goes wrong, he can take you to court. If that house burns down and you survive, you're still completely and totally fucked.

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  • SoggybiscuitSoggybiscuit My food is teasing me. WVRegistered User regular
    edited May 2011
    Mushiwulf wrote: »
    You are wiring a lamp with, at most 5 sockets. The wire is rated for 10 amps. That is over 1000 watts. Unless you think it is likely someone will put 200 watt bulbs in those sockets, you should be fine.

    Bad idea. Follow the NEC, do it right the first time. You can save yourself a lot of headaches by doing this.

    Make sure you purchase the correct wire type and size. Remember, the ampacity of the wire has to equal or exceed the current rating of the breaker.

    Here is a pretty good chart for reference http://www.stateelectric.com/formcalc/ampacity.asp . It is highly unlikely you will be able to buy any #18 or #16 THHN at lowes or home depot.

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  • MushiwulfMushiwulf Registered User regular
    edited May 2011
    He is wiring a lamp. There is no wiring going on in the walls.

    NEC Article 400, Table 400.4 Lamp cord, voltage 300, AWG 18-16.
    400.7 Uses Permitted (2) Wiring of luminaires.

    We also have 402.5 Fixture wire, allowable ampacities for 18 AWG, 6 amps.
    240.5(b)(2) Fixture wire shall be permitted to be tapped to the branch-circuit conductor of a branch circuit in accordance with the following:
    (1) 20-ampere circuits -- 18 AWG, up to 15m of run length

  • SloSlo Registered User regular
    edited May 2011
    Speaking as an electrician here, a lot of electrical stuff will work if you do it below suggested ratings, but you won't notice for a week, a month, or a year a lot of time. Sketchy stuff, especially when it's not even your house and you're playing with stuff that can seriously damage the property.

    That being said, 18 gauge should be ok for the sockets themselves, but you need to be really careful and tie those wingnuts on properly, because if they get loose, you're going to have some issues (Potentially fiery ones). Also: Running wires in parallel like you're suggesting isn't up to code up in Canada, but then again, I'm a bit confused as to what exactly you're trying to do here.

    I'd never try to do something just barely touching the code limits, let alone something beneath them. Electricity is dangerous stuff.

  • bowenbowen Registered User regular
    edited May 2011
    Sounds like he's making a Y junction of some sort, hence the junction box in the wall. As far as I know, as long as you wingnut it in the junction box, in a wall, you're okay.

    Seems like he's running a length of fire(edit wire, but that is potentially what he's doing) to two different locations. I'm concerned though, because his breaker probably won't trip properly.

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