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I also wholeheartedly approve of this thread. I have a house that was built in 1947. I think I am only the second person to ever live in it. Prior to my purchasing this house it was rehabbed by some investor guys. The contractors did a "decent" cheap job. They clearly cut a bunch of corners in several places but I have learned to live with it. They didn't pull any permits for their work though and it's obvious that it wouldn't have passed if they had. So, regarding the electrical work in the house. I have replaced a couple of cheap duplex outlets that were getting hard to plug in/out of. The wiring on the old circuits appears to be a cloth/really old rubber variety and crumbles away when you bend them. This happened on one of the outlets to a small portion of the hot wire. I wrapped the small portion in electrical tape and shoved it back in the wall. What kind of wire exactly is this likely to be? I can't recall exactly now but I am fairly certain even the old wiring is 3-wire. The new circuits they ran don't make any sense. I have all sorts of circuits with only one outlet on them. A bathroom they made upstairs has a single GFCI outlet near the sink and another outlet on the floor which is on a different, non-GFCI, circuit. All sorts of craziness like this. There are also outlets at the kitchen countertops that are not on GFCI circuits (some are old, one is definitely a new circuit). The circuits run to the bedroom are not AFCI protected, though to be fair I do not believe any work was done on them. Anyway the new circuits are all 12/2 (w/ground) Romex. My basement is unfinished and there are several spots where the wires are run on the bottoms of the floor joists, which as I understand it is against code. There are also several spots where they just drilled a single 3/4" hole and shoved like 7 12/2 Romex wires through it. I am pretty sure this is a situation where the current capacity of those wires must be derated. I am sure they did not do the math on it. I also ran a dryer circuit myself and made a mistake regarding code. I used NM-10/3 wiring, but just ran it along the bottoms of the floor joists. I was going to use FMC 10/3 but some dumbass at Lowe's was like "Oh you don't need that, this stuff is half as expensive" and I believed him against my better judgement. One day perhaps I will replace the wire with a proper run. In the course of remodelling the house I am sure they replaced the breaker box with a brand spanking new Sqaure D QO (maybe QOU, can't recall at the moment) 100 amp panel. I believe the service to the house is 100 amp as well. I should also mention I have an AC unit (that they also installed) which has a heat pump and electric auxiliary heat. Amazingly we have not tripped any breakers with the heat pump/aux heat, dryer, and whatever appliances running. I was sure worried we were dancing close to the 100 amp limit. Prior to them installing this breaker box I am pretty sure it was just a fusebox or something, though I have no evidence of it. The service to the house, well there is no ground rod that I can find. It looks like just hot and neutral to the pole, so I assume the ground is wired into the neutral in the breaker bus bar. I gather from this thread that this is very bad and I should have a real ground rod installed. Would installing a ground rod constitute an "upgrade" that would require all upstream wiring to be brought up to code? I will take pictures of all of this shortly hopefully. I'm just curious what the relative "omg you need to have that fixed by a professional" factors are for all of these things. I'm an electrical engineer (though I do communications systems/signal processing), so I am familiar and comfortable generally with electricity but by no means a mains power specialist or professional. I'm a bit OCD as well and thus all of these possibly minor things really bother me. I don't like half-assed and possibly dangerous work, especially in a house I live in. Lastly, I want to install a fan in a box that just has a light right now. The light is on the same circuit as another light and are controlled by two switches (as in two switches both control both lights). I want to remove the second light from the switch circuit. I am pretty sure this will require running some new conduit to it. This fan will be on my top floor. I live in a cape cod house, so this is also my attic. I have access to a crawl space where there are outlets fed by some old looking FMC, haven't looked at the wires yet. Can I just branch off of a duplex outlet inside of the box or do I need a separate junction box before the outlet? I gather from reading that I would be okay just tossing the new FMC through the 4-5" of clearance between the room insulation and roof until I got to the triangular void at the top (which I have no way to get in to, aside from taking out the ceiling drywall). Then it would just be a hide and seek game to get it pushed over to the hole. I would probably put the new set of switches above the duplex I branched off of. Is this a reasonable approach? Thanks! Lucid Smog fucked around with this message at 08:18 on Mar 30, 2009 |
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Mar 30, 2009 08:16
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Elendil004 posted:It's not what I'd call a duct bank though, who knows. Do you know what fiber optics run per foot? Are there differing grades of cable? There are several different types of fiber optic cable. There are multimode and single mode fibers. Chances are you want multimode fiber for this. The fiber itself is really all the same except for the actual sizes of the fiber (inner and outer jacket measurements). The outer jacketing however comes in many different styles. Cheap, plenum (fire safe), armored, liquid filled for direct burial, etc. Fiber itself is very inexpensive, though you have to buy thousands of feet for it to be "really" inexpensive. For a 500' run you should be alright. Your problem is going to be terminating and pulling the fiber. Terminating fiber is very expensive and not something you are likely to be able to accomplish on your own, nor will you have the expensive toolset to do so. If you want a custom built to length fiber pre-terminated, it will cost like 500% more than just the fiber itself easily in my experience. Also, you can't just take a 500 foot cable and yank it down the tube. The stress on the cable would likely be too great. You would probably want a wire backed cable so that you could pull the wire, rather than the plastic covered glass. You will get absolutely no interference in the fiber from electrical or anything else for that matter. However, no, you can't run an analog phone over fiber. Analog phone lines aren't "data" and they carry voltage, which fiber is incapable of doing. There might be some crazy device that will convert analog at both ends for phones, but it would likely be very expensive since they probably only sell like 20 a year. You can run data over the line and use media converters at both ends to get it to get to Cat5 again. You could run VoIP over this data network. Another thing to consider, though I'm not sure it's totally appropriate for your application: often when running fiber over a decent distance you will run at least 2 pairs of fiber. The fiber is generally inexpensive and the hard part is actually running it. That way if one ever fucks up for some reason you've got a spare already, or if you want more capacity later you can do that. Also, in regards to the 100m Cat5 distance limitation: you might get away with a longer cable run. Performance will be degraded, for sure, but I would guess that some data would still get through successfully. You would have to decrease the MTU of both link ends though, by a lot. One of the reasons for the 100m limitation is because it guarantees the the "carrier sense" collision detection can work. Basically it means that both ends can't transmit at the same time and not notice that they did this. It has to do with the speed of electrons down the cable and the amount of time it takes to send 1500 bytes over Ethernet. Lucid Smog fucked around with this message at 03:11 on Apr 13, 2009 |
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Apr 13, 2009 03:01
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Elendil004 posted:thanks for the advice, I might have somebody at work who can terminate the optic cable for me so that might help. Thanks for the advice on the wire-backed cabling, sounds like a good idea. If you know someone who can terminate the fiber, that's great! I have never actually gotten a price on terminations, but I have somewhat guessed that it's around $100 per termination. If you pull four strands, that's eight terminations. Yikes! I couldn't find a link to this one place I found that was pretty well priced and had every kind of fiber cable in bulk you could want. I'm sure I've seen them wire backed before, though some have pulling eyelets that you can use to some effect as well. For your distance and application you're going to want 62.5/125 multimode fiber with either ST or SC terminations (the termination type doesn't really matter, as long as you have either a fiber card in a computer/router/switch or a media converter with the same type of jack). Regarding the phone line: if you don't want to run 500 feet of phone cable (I'm not even sure you could, the voltage loss over 500 feet of low voltage cable might be a lot) you could pretty easily run VoIP over the fiber data link. Buy an FXO device and put it at your house where the physical POTS line from the phone company is. Put an FXS device at the other end. Buy the same equivalent models from the same company. It should be pretty straightforward to tell the FXS device at the far end that no matter what you mash in for numbers, just forward it to the FXO device. It should also be pretty simple to tell the FXO to just willy-nilly dial out whatever numbers it receives on the POTS line from the FXS device. Then it will appear as though you have normal phone service and none will be the wiser that there's actually a VoIP step in the middle.
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Apr 15, 2009 14:19
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Elendil004 posted:Do you have a link to any resource that describes the different (ST/SC) terminations and the types of fiber? Why is 62.5/125 the best for my uses and what does it mean? 62.5/125 indicates the size of the actual fiber and the jacket, in millimeters. Basically multimode fiber is useful for shorter distances, like less than a few thousand feet. It allows you to use cheaper electronics (like an LED media converter). If you use single mode fiber all the junk that goes along with it will cost more. Wikipedia has a good article (which also seems to suggest that 50/125 is becoming the new standard since you can use a laser rather than an LED and get 10Gb/s, if that matters to you): http://en.wikipedia.org/wiki/Multimode_fiber There is also a Wikipedia page on fiber terminations: http://en.wikipedia.org/wiki/Optical_fiber_connector Basically the most common terminations you see on multimode fiber are ST, SC, or LC. There really isn't much difference between them, from your perspective. It's mostly just what type of equipment you have and how many fiber connections you need. For you, ST or SC are good because there is a lot of relatively cheap media converters around that are built for ST/SC terminated 62.5/125 multimode fiber.
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Apr 15, 2009 22:13
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Big Steveo posted:As an electrician in Australia, I am horribly confused with all you American talk. As a curiosity, anyone care to give me a low-down on the following: I'm just an electrical engineer, so I will leave many of the comments to actual professional electricians, but I will answer a few things (to the best of my knowledge) quickly: 1. Who knows. History. We have a whole country full of 120V distribution equipment and devices which use it. I think a switch to a higher voltage will probably never happen. People are generally not even aware that there could be another option and that it might be better (from a cost perspective at least). 2. Yes, it is because of the lower voltages. It's equivalent to having 100A service in Australia, which I would guess is probably not too abnormal? Yes, it would be beneficial to switch to a higher household voltage if only to save on the cost of copper conductors. Many industrial applications (well, in a data center at least) can/will use a tap across two phases of a three phase supply, which in our case is about 208V (our standard three phase supply voltage is 415V I believe). 3. I've not seen cables that look exactly like that (except the top one). What you appear to have there is what I would call NM ("Romex") cable. It's a plastic insulated jacket around the conductors. The conductors run together through the cable, not separated like in your picture. The ground conductor is typically not shielded (covered in plastic). You can look up tables for such things. By gauge people mean AWG, American Wire Gauge. Current code requires AWG 12 for most runs and can be used up to 20A; this is about 2.05mm/3.31mm^2. AWG 14 is permitted for end runs to lights and can be used up to 15A; this is about 1.63mm/2.08mm^2. 30A circuits requires AWG10 and, at least in the few cases I've needed it, are generally 240V circuits. (American homes are fed from a 3-tap transformer and thus get the center tap as "neutral", 180 degree phase as +120, and the out of phase equivalent at -120V. The breaker boxes are wired such that one leg uses the -120V as neutral and "neutral" as hot, so you still get +120V while the other leg uses "neutral" as neutral and +120V as... +120V) 5. Residual Current Devices are called Ground Fault Circuit Interrupters (GFCI) and are required in all circuits in damp/wet areas, outside, in bathrooms, and at kitchen countertops.
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Apr 27, 2009 05:09
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grover posted:Why are you using 50Hz in Australia instead of the much better 60Hz? I have heard many times that having a higher voltage will result in more electrocutions. I don't get it. Yes, an arc will occur over a larger distance... but most people are not ever near electrical arcs. It seems just as dangerous to me. There seems to be some endless debate about whether it's "better" to have more voltage/lower current or vice-versa, but it sure seems like a moot point. I've heard from some British electricians who have seen U.S. electrical work that they are amazed at how "lax" American rules are. I didn't ask specifics but they were sure under the impression that most U.S. homes would fail a U.K. miserably. All hearsay though! I just looked it up: the 2008 code does require AFCIs basically everywhere! That's crazy. There are none in my old house. I've heard that they have a much higher tendency to trip incorrectly than normal overcurrent protection breakers. Is that true or just people wanting to complain about something? edit: I have a question about wiring in a U.S. home. I have a 10/3 NM, 12/2 NM, and 12/2 MC cable. I have an unfinished basement with a cinderblock foundation. I want to put some outlets on the walls. I plan to run a 4"x1"x4' board from the ceiling joists where the NM wiring is run down the cinderblock wall and fasten it with masonry screws. Then I want to mount a handy box to said piece of wood and run a cable to it. Can I just run MC cable and secure it properly, or does it have to be in EMT or Schedule 80 PVC up to the joists? Can I run MC cable EMT/PVC (I have more of this than 12/2 NM). I am guessing I cannot just staple NM to the wood as that is pretty exposed. Similarly I ran an outlet for a dryer when I first moved into the house and definitely didn't do it right. I want to go back and fix it now. Here's what it looks like (including my breaker box):  Click here for the full 1000x667 image.  Click here for the full 410x1000 image. Things that I think are wrong: NM cannot be just attached to the bottom of the joists like that, it needs to be up at least 1.25" in holes drilled through it, or protected in EMT/PVC 80. I used some EMT straps near the end by the dryer outlet (you can see them in the picture). I just didn't know any better, but I have NM staples now. I haven't changed them out because I think the NM has to go anyway. Also I think the NM running along that wood has to be protected too. Everything except that orange cable coming out of the right side of the breaker box (10/3 dryer wire) is not my doing. I put those orange labels on all of them to identify which circuit they were so I trace them all out. Anybody notice anything really egregious just from that picture? Lucid Smog fucked around with this message at 14:00 on Apr 27, 2009 |
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Apr 27, 2009 12:34
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IsaacNewton posted:I'm not an electrician by any stretch (and I'm Canadian anyway) but AFAIK that panel should be on a plywood sheet or something so that the wires can be stapled close to the panel. That would have been a good idea, the plywood. There is plywood around it to staple things to, but generally they just unstapled. Oh, I didn't realize it was that tight. I had an extra ten feet, but didn't want slack in the line so purposefully removed as much as possible. grover posted:Twice the voltage = twice the current. Ohms law. Twice the current means a higher incidence of fatal current going through the heart. Ohm's Law is V = I * R. If you increase the voltage by a factor two, the equivalent current is decreased by a factor of two for the same load. That's why you can run smaller conductors at higher voltages (and main distribution lines aren't 1 meter think copper). So, you increase the voltage to 240V but the current for the same body resistance is also half. If anything I would consider it safer, as I am usually quoted a current to stop a heart (in the low milliamps range) rather than a voltage. Though I am certain that the voltage has a role to play in killing someone. Either way, you can get electrocuted and have it completely bypass your heart. You're likely to feel very bad and have muscle spasms, but not die. Or you can be that unlucky bastard who gets killed by a ringing phone line.
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Apr 28, 2009 01:59
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babyeatingpsychopath posted:You can run NM exposed if you want, but you can't staple it to the bottoms of the joists. If you don't want to drill holes in your joists you can run it in EMT which would be strapped to the joists. NM cable must be secured within 12" of any box and within every 4.5 feet thereafter. Run between holes in joists counts as supported. Cool, thanks for the info. I didn't realize I could run it exposed on a wall but not on the joist. There are already enough holes in that joist, I don't really want to be cocking my head up and drilling another 30. I'll probably run it through EMT, as soon as I find a cheap way to bend it (current thinking is to buy a $33 bender from Lowe's and return it). Can I use 3/8" EMT for 10/3w/ground or do I need to move up to 1/2"? I've never been clear if I could run NM in EMT of it had to be bare THHN/THWN. The MC will be running parallel to a joist so that is nice and easy. There are no plans to finish any of the basement in the near future, so I will leave the MC/NM as it is probably. Also here's a few more pictures of dubious work:  Click here for the full 1000x634 image. This picture depicts the bulk of cables that somebody else put in, along with my dryer wire, my ancient unused telephone service entrance, the incoming RG-6 cable line, and a white Cat-5 ethernet cable.  Click here for the full 1000x867 image. Here you can see how many of the circuits are run, through a single 5/8" hole I believe. I'm pretty sure if you do this you can to de-rate the current carrying capacities of those wires for heat. For some dumb reason many circuits are 14/2 romex. The yellow run runs to a bathroom that the people who flipped the house before I bought it installed (it powers a GFCI receptacle and a single light). All the 14/2 cables are on 15 amp circuits and nearly all run to the kitchen to power outlets and dedicated receptacles for things like fridge, microwave, range (gas range). Thanks for your input!
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Apr 28, 2009 03:27
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grover posted:No, that's completely N/A. Think about it. R will change if you've got sweaty hands, but it isn't going to change depending on which wire you grab. Double V, and you double I, too. The power through your body actually quadruples when you double the voltage. Yes, you are right. I was confused. I was stuck thinking of high voltage transmission lines. There there is an inverse relationship between current/voltage there thanks to the transformer. The point being that a constant power level is maintained but the current is decreased by many factors which mitigates line loss. Line loss being proportional to current^2. If you only change one variable by a factor you do increase total power dissipation by a factor of four. I can see why 220 might be a bit more dangerous. (of courses, their circuit breakers are probably 7.5/10 amps since they don't need to deliver any more power to the household circuits than we do)
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Apr 28, 2009 13:43
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Big Steveo posted:I'm reading from the AS/NZS3008 (Australian/New Zealand Selection of Cable) The cables are like that for about 2" every 16" or so inches (every time it goes through a floor joist). The yellow cable is a 12AWG power cable while the white ones are 14AWG. They probably should be derated to some degree, but I think those cables are the least of the fire hazards in my house. I really need to go install AFCI circuit breakers all up in my panel because there is tons of old cloth jacketed cable in corrugated metal conduit (does this conduit act as the ground? There are only two cables in these conduits I've seen but all the handy boxes have been metal so I'm guessing/hoping there is a real ground).
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Apr 29, 2009 12:55
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How can I trace circuits without having them be live? All of the old wiring in my house is in some sort of corrugated metal shroud (looks like AC/MC) and the actual wiring is two-wire cloth (well, looks like cloth) insulated. I have a conctactless voltage probe but it doesn't work through the metal shroud. I am not interested in getting electrocuted, but I can't think of any other ways to figure out which run goes to which outlet/switch and where the power is coming from. I was planning on opening up the junction boxes in my basement and probing the wires with the contactless voltage probe while having my wife flip some switches to try and figure it out. Later work will probably see me turning off the breaker and actually disconnecting some of the junctions so I can see which direction the circuit is going. Safer/better options would be appreciated.
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May 2, 2009 14:12
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chryst posted:These seem to trace from an outlet to the breaker. Is there something like this that'll trace the wires inside the walls, so I don't have to tear out drywall to figure out where each branch ends up going when I want to run a new 3-conductor wire? The Amprobe ECB50A appears to serve this function. It was on the Grainger website too, but the site I linked is cheaper and has links for the instruction manual and datasheet. Is it not really going to work, babyeatingpsychopath? I'm tempted to order it tonight, though I am suspect that it will work through AC/MC conduit as metal has a way of shielding low frequency signals.
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May 5, 2009 01:07
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babyeatingpsychopath posted:I'm not going to say it won't work, but I'm inclined to believe your suspicions that it won't work on that cable, which is probably BX. The tester like that (I think it was a Greenlee) didn't work if the cable passed through a metal stud. It would find the cable until it went through the stud, then locate the whole stud with nothing past that. The transmitter says 8-10kHz; it may sufficiently energize cable armor to work fine. For $70, you have a really good circuit tracer if nothing else. I bought that Amprobe circuit tracer. I am still getting used to it, you're right about it being a bit tricky. It makes sounds like those cheap Halloween scary toy things. It does appear to work through the BX cable, and it does also appear to work through a plaster wall (and more BX cable). It also looks like it injects the signal through the ground lead (and possibly through the hot as well), because even circuits that are switched off (with a switch, not the breaker) still set it off. Also my ground wire from the breaker to the cold water pipes always sets it off too. I think it will have been a good investment, though I am still trying to get used to it.
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May 9, 2009 18:09
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I know that I need 40% fill for 12/2 NM cable. How big of a hole do I have to drill through my joists for it? Is 3/4" sufficient? edit: Also I am under the impression that I can run NM cable along an unfinished basement wall to receptacles and such. But I am not allowed to run NM (unprotected) along the ceiling joists of said unfinished basement. What's the reasoning here, assuming I'm even right? I feel that I am much more likely to gently caress up cables at eye level than ones over my heard. Seems like the ones on the wall need protection too. Lucid Smog fucked around with this message at 12:37 on May 28, 2009 |
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May 27, 2009 19:34
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fast5c posted:Your advice was spot on, thank you! It worked perfectly the first try...well sorta. CFLs and most dimmers work at increased frequencies from the 60Hz coming into your house. You are hearing harmonics caused by the device. I don't think there is anything you can do about it, other than listen to loud music and damage your ability to hear high frequencies. Most dimmers nowadays I would describe as "switching" dimmers, meaning they modulate the power on and off to the light which changes the duty cycle. This is how you're actually using less electricity when the lights are dim, the light is actually being "shut off" and "turned back on" many many many times per second. You could maybe find a dimmer that was just a simple rheostat/potentiometer, which means that it will always be drawing full power and just dissipating that which you don't want in the form of light as heat at the dimmer. It sounds dangerous to me and I doubt you could find something like that at Lowe's.
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May 29, 2009 12:48
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