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At some point I'll need to start figuring out the details of how I'm going to wire up the workshop I'm building. Aside from reading the building code, are there any other recommended resources? Super-high-level thinking at the moment is put a 60-amp breaker on my main panel, run that out to a sub panel, put the following circuits on the sub-panel: * 15-amp lights * 20-amp for half the workshop's outlets * 20-amp for the other half * 30-amp for a 220v circuit That's all approved already by the planning board, but I need to figure out specifics, stuff like what gauge of wire to use for each circuit and for the run from the main panel to the subpanel, how exactly outlets get wired up, how to properly dig the trench the run will be using (and how to protect the trench once dug), how to run wire inside the workshop, etc. Surely there are books that set this stuff out; I'm just looking for a recommendation on one. My electrical experience is next to zero; the most advanced stuff I've done is replacing light fixtures and wiring up dead-simple signal (TTL) lines for robots.
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Jul 28, 2015 22:03
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Yes, this is going to be permitted work. I was hoping however that I could do all of the grunt work myself (like digging the trench, running conduit, hooking up basic outlets, etc.), have a contractor come in and make certain I haven't done anything dumbassed and/or do any complicated bits I'm afraid to tackle myself, and then have the inspector come in. Partially this is an attempt at a cost-saving measure, partially this is a subject I want to learn about.
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Jul 28, 2015 22:33
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Yeah, certainly I don't want to fail inspection. That's just a waste of everyone's time. So what I'm asking for is resources I can use to learn how to do it properly. Hiring someone to come over and teach me is one possible approach, but it seems likely to be more expensive than a book / some YouTube videos / etc. Plus my experience with talking to experts in the past is that they don't necessarily make good teachers; they'll know what to do, but they do a crappy job of explaining why, which is just as important IMO. Granted I'm the guy with no experience here, so feel free to correct me if I'm wrong. But my hope was that I could learn enough that I could just hire someone to come in, look at what I've already done, go "yup, that looks correct", and then finish off the tasks I didn't feel up to handling. Re: California, I'll certainly be reading the code before I start work on the wiring. I did that for the construction aspect of the project, after all. But some basic education would be helpful for understanding the code, just like how I bought some books on house construction before I started reading the code for how the workshop could be built.
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Jul 28, 2015 22:51
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babyeatingpsychopath posted:Really, if you read the code book, you'll be fine. Outbuildings are fairly straightforward, but they may be residential still. Thanks for this and the other info. I guess I'm mostly just looking for a primer? I know when I first tried to read the construction code I was constantly trying to find definitions for jargon terms (like what the heck a bonding screw is), and it wasn't until I'd read some more naturally-written texts that I actually understood what was going on. FWIW because I'm not planning on putting up drywall, all of my interior wire runs have to be in conduit as well, according to the planning department.
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Jul 28, 2015 23:50
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Yikes, okay. That handbook sounds like exactly what I was looking for, except way more expensive than anticipated, probably because it covers the entirety of the code. Maybe I should just go on Amazon and look for a "basic house wiring" book or something. All's I need is enough grounding (so to speak) in the subject that I'll understand what the code is talking about.
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Jul 29, 2015 14:40
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XmasGiftFromWife posted:I was typing some smart rear end response but decided to just advise you to check your library. If they don't own it they can get it through a library loan. Dur, this is a good idea.  I keep forgetting libraries are a thing.babyeatingpsychopath posted:When I rewired my entire house from scratch (including new service panel) before I became an electrician, I used the Black and Decker Complete Guide to Wiring. It's full of great pictures. Then I opened up the code book and actually read the relevant sections for code calculations. The code book isn't that bad, honestly, and the new versions are much clearer than the old. Awesome, thanks for the recommendation. quote:Back in the early days of this thread, people would say "I'm trying to install an X-amp subpanel Y-feet away, and I'm using Z wire. Is that right?" and the pros here (myself included) would run the numbers and give the yes/no. And I'll probably do something similar once I've done my research. At the moment I wouldn't even know what's vaguely close to reasonable, so I'd just be wasting y'all's time.
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Jul 29, 2015 16:47
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Rubiks Pubes posted:I do have attic access so that will make the whole process easier. Is it OK to use higher gauge if it isn't necessarily needed You mean lower gauge: lower numbers are thicker. 14ga is thicker than 16ga, etc.
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Aug 10, 2015 21:34
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H110Hawk posted:Awesome, thanks. I have a 3-pack of tamper resistant leviton 'smartlockpro' gfci's I originally bought for the kitchen. You should only need one GFCI outlet per circuit, since it detects ground faults on the entire circuit, not just for things that are plugged into it.
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Sep 21, 2015 19:46
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I'm eventually going to need to install electrical service in the workshop I'm building in my back yard. I plan to do the wire runs myself, but I may hire an electrician to do the service hookup / subpanel install, depending on how confident I'm feeling. The main problem is that the planning department requires all wiring in the workshop to be in conduit, since I'm not finishing the walls, just leaving the studs exposed. I'm not certain how to go about running conduit into the walls given that I didn't do so at the time they're built. Can you feed conduit in when your max distance between studs is 16" (well, 14.5" given they're spaced 16" on-center)? It occurred to me that I could drill holes from the outside of each wall and install straight conduit that way, but I'd want to do that prior to putting up the housewrap (currently it's just plywood on 2x6s). Is this a legitimate approach? Any other suggestions?
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Sep 22, 2015 22:31
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kid sinister posted:You would need something flexible. You would need MC like Motronic said, or flexible conduit like FMC or ENT. MC would be nice because it already has the wires threaded through. And this is why I ask questions -- I don't know what I don't know. Thanks for the advice, guys; I'll give them a call and hopefully the flexible stuff (to be clear, we're talking about products like this, right?) will be what they were thinking of. As long as the turning radius is less than a foot I should be okay for everything.
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Sep 23, 2015 01:37
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Checked in with the building and planning department, and FMC is absolutely allowed. Thanks for the advice!
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Sep 25, 2015 16:06
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angryrobots posted:Get MC cable when you go to buy material though. It's got the wire already in it. That obviously saves you from having to fish the cable out, but I'd guess it makes it trickier to cut the cladding off where you need to go into a junction box or switch or the like. Would I need a special tool (like a pipe cutter or something) for this? I had been figuring I'd just cut the conduit with a hacksaw.
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Sep 25, 2015 17:58
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kid sinister posted:I did this too, with pliers and wire cutters. MC is covered in aluminum, so it cuts pretty easily. They also make little plastic inserts for MC that go around the wires and you push it in between the wires and sheath. It helps protect the wires against any burrs. Great info, thanks! Always good to hear from the more experienced before trying something for the first time. I think I'll stop by the local scrap-metal place and see if they have any spools of MC nomex I can make use of. I can probably use scraps just fine since the runs won't need to be all that long.
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Sep 25, 2015 20:36
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The plans for my workshop spec 20-amp circuits for most of my outlets, which by my understanding only require 12-2 romex. However I'll be running stuff like power tools and dust collection off of those outlets. Would there be any particular benefit to upgrading those circuits to 10-2 romex? I also have a couple of 220V 30-amp circuits in the plans; is there any reason I should go above 10-2 romex for that?
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Sep 29, 2015 20:40
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Sounds like it's not going to be a big deal then. The runs aren't going to be long -- if I loop around the entire workshop that's still only 80 feet, and more likely I'll just do one circuit down half the workshop and a different one down the other half. Thanks for the info!
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Sep 29, 2015 23:09
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Zhentar posted:The rebar inside of concrete can be a pretty great grounding electrode. That reminds me: when I got the slab poured for my workshop, I included a 25' line of (IIRC) 6ga copper wire to use as a ground. Then I accidentally snapped off the part of the wire that extended out of the slab. Is that in any way recoverable or am I stuck with installing a grounding stake instead?
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Dec 9, 2015 03:18
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dwoloz posted:This is sadly the correct answer (most likely). It all comes down to your inspector though. In my parts, new construction _always_ needs a Ufer ground; cannot sub for a ground rod The foundation inspector recommended it, but the way he described it, it was basically as an easier/better option vs. installing a grounding round. He certainly didn't make it sound mandatory. This is just for an outbuilding though (albeit one that will have its own subpanel), so the rules may be different for stuff like houses.
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Dec 9, 2015 06:05
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Preface: I've never done any wiring work before. I've read some educational material (including a bit of the Black&Decker Complete Guide to Wiring), but that's about it. I have a receptacle that controls the garbage disposal in my sink. It has two outlets, both of which are controlled by the same switch. I'd like to convert one of the outlets so that it's on all the time, so I can use it to run my dishwasher. As I understand it, this would require me to do the following: 1) Turn off the breaker that controls the receptacle. 2) Open up the switch and receptacle boxes. 3) Somehow run a new cable between the two boxes. 4) At the switch box, pigtail the live (black) wire of the new cable onto the input live (black) wire of the switch using a wire nut. 5) At the receptacle box, wire the live (black) wire of the new cable into the input (left side) of the outlet that I don't want to be switched. I may need to replace the existing receptacle with one that allows the two outlets to be independently wired. 6) At the receptacle box, wire the neutral (white) wire of the new cable into the output (right side) of the outlet I don't want to be switched. Pigtail it onto the existing neutral wire using a wire nut. 7) At the receptacle box, wire the green (ground) wire of the new cable onto the grounding screw of the receptacle. Is that it? Any advice for accomplishing step 3? I'd like to minimize the amount of damage I do to the wall here, but I have no clear idea of how the switch and receptacle are currently connected; the switch is up and to the left of the receptacle, far enough that it has to pass through at least one stud. Alternately, I could access the other side of the wall via the bathroom, and just run an additional GFCI outlet off of the bathroom circuit. I have much easier access to the wall that way (no countertops / tile / plumbing in the way the way they are in the kitchen), but it'd mean very nonintuitive house circuits -- one circuit would control my office, the downstairs bathroom, and a single outlet in the kitchen. I mean, not that the circuits in this house make a whole lot of sense to begin with. If I were to do this I'd just pop some of the drywall off and be able to clearly see where the cable needs to go; in fact I think it'd be a straight run down from an existing outlet in the bathroom. And the actual wiring should just be a matter of pigtailing black with black and white with white, right? Opinions?
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Jan 10, 2016 21:54
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slap me silly posted:Maybe or maybe not. Power may be coming in at the switch box, or it may be coming in at the outlet with a loop sent out for the switch. You won't know until you open it up. First case requires the "Somehow run a new cable", which is some underpants gnomes level poo poo by the way. Second case is easier, but you still might need to buy a new outlet if you can't separate the one you have (assuming it's single-gang). I'm pretty sure it's coming in at at the switch; at least, I remember looking at the outlet awhile back and not seeing enough wires for it to make sense that it came in to the outlet, then went to the switch for power. Not really surprised that "somehow run a new cable" is not very likely. This is for a dishwasher though, not a light; is that a better thing to put on the bathroom circuit? 
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Jan 10, 2016 23:50
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magic mountain posted:The proper solution here is really a direct home run and a new dedicated dishwasher circuit but that's kind of a pain in the rear end. Yeah, the wiring in this house in general needs to be updated (I think I still have some knob and tube wiring in the attic, for example). But I can't add another breaker to the breaker box because there's only one remaining spare spot and I need that for when I add power to my backyard workshop. Updating the wiring and adding a new circuit breaker box with room for more circuits is one of those "once I'm more financially secure" projects. Probably also a "once I know I'm going to keep living in this house for the next ~10 years" project.
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Jan 11, 2016 00:11
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I swung by the scrap metal shop today to pick up some armored cable for my workshop project ($2 per pound!). I noticed that they had some 12-4 cable along with the 12-2 stuff I got, and I was curious: is it actually allowed to use an over-specced cable and just leave some of the wires in it unattached? Or are you only allowed to use that kind of cable in situations where you are required to use that many conductors?
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Mar 12, 2016 00:39
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babyeatingpsychopath posted:You can run 12-4 AC/MC if you want, and just mark both ends of the unused stuff as "for future use." No problems there. It beats having to run more stuff in the walls later. There may be hidden gotchas later if you try to just use the extra circuits (breaker ties for everything sharing a neutral, etc) but if you wanna pay for the copper to just hang out in your wall, that's on you. Okay, cool. I wouldn't know what to do with the extra wires honestly, but sometimes it's just easier to find a coil of 12-3 in their "random pile of electrical cables" section than it is to find 12-2.
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Mar 12, 2016 01:32
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Hashtag Banterzone posted:That seems like overkill. Is going 24" deep really necessary? I'd rather not rent a trencher if I don't have to. I asked the local building department here in California how deep the trench had to be for my conduit to electrify my workshop; they said 24".
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Apr 24, 2016 15:10
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You can buy multipack 1-foot-long extension cords. They come in handy surprisingly frequently. Not just for stuff like your vacuum cleaner; you can also use them to get full use out of the ports on a power strip, for example.
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Jun 20, 2016 02:38
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As I understand it (and I don't claim to be an expert), you need drywall between the garage and the house to serve as a firewall, since the garage tends to have flammables in it, but the rest of the garage doesn't necessarily need to be drywalled. Still, it doesn't take much effort do do a half-assed drywall patching job that will meet code. I wouldn't want to leave holes in my ceiling, personally.
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Jul 14, 2016 17:25
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Motronic posted:That's what I do for my barn. It was just easier to throw three expensive GFCI breakers at the problem for the outlet circuits and be done with it. The building department mandated that when I get the sub-panel installed on my workshop, all the circuits be GFCI protected.
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Jul 17, 2016 15:27
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kid sinister posted:That doesn't necessarily mean GFCI breakers, especially if the wiring hasn't been installed yet. Plan ahead for GFCI outlets, they cost 3-4 times less. Or did they specify GFCI breakers? I admit I don't recall 100%, but I'm pretty sure they just said "GFCI protected". Is there a functional difference between GFCI breakers vs. GFCI outlets in terms of protection afforded? It seems weird that the breakers would have more of a price premium than the outlets would. One of my circuits is going to be just for lights, and another is to be 240V; I expect I'll just get GFCI breakers for those. Well, I guess I could install a ceiling outlet on the lights circuit... At least there's no convenience issue, since the panel will be right there on the wall.
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Jul 17, 2016 19:26
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Uncle at Nintendo posted:All this GFI and garage discussion piqued my interest for obvious reasons; since I am going to Lowe's today anyway to buy some stuff to solve this electrical situation in my garage, should I buy 3 GFI outlets? 2? 1? None? You only need one GFCI outlet per circuit; it protects the entire circuit. I haven't been paying super-close attention to your saga in this thread, but do you know how many circuits are in play here? Then get at most that many outlets.
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Jul 18, 2016 14:57
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kid sinister posted:There is no code requirement that exterior lights and outlets have to be on their own circuits, however there are some outlet-only circuits that aren't allowed to be shared at all: kitchens, bathrooms, laundry, etc. Still, it is a good suggestion to have outdoor outlets separate. That way your Christmas lights won't trip the breaker and kill the lights inside. That reminds me: is a kitchen allowed to share circuits with a bathroom, or vice versa? In other words, is the rule "this room must have its own dedicated outlet circuit", or is it "this class of rooms may not share outlet circuits with generic rooms"? I'm guessing the answer is the former (i.e. kitchens can't share with bathrooms), but I figured I'd check.
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Jul 18, 2016 18:10
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Bah, oh well. Thanks for the clarification. For context (pretty sure I've discussed this in the past), I have a switched outlet under my kitchen sink that powers the garbage disposal. I added a dishwasher, and the sensible place to plug it in would be to get it into that same outlet. But that means that every time I want to use the dishwasher, I have to go under the sink, unplug the disposal, plug in the dishwasher, and then flip the switch. Fixing that would require rewiring the switch (the entire outlet is switched, not just one of the receptacles). The only other circuit in the area I can plausibly hook into to add another outlet is the bathroom, on the other side of the wall. Otherwise we're talking trying to fish cable through the wall horizontally without tearing out cabinets and countertops.
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Jul 18, 2016 18:35
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kid sinister posted:First off, which circuit is your disposal on? Have you peeked at that disposal outlet yet? Turn off the power and pull that outlet out of its box. How many wires are in there? What colors? The outlet's a mess (just generally dirty, with old wires), but I've looked at it in the past and am confident that it's a fully-switched outlet. I haven't checked what circuit it's on yet, but I assume it's on the same circuit as the rest of the kitchen outlets.
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Jul 18, 2016 19:30
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kid sinister posted:Define "fully switched outlet". Again, how many wires? I'll get a photo for you this evening, but what I meant was that both receptacles on the outlet are controlled by the switch. If I wanted to have a half-switched outlet with one receptacle always-on, AIUI I'd have to run more wires from somewhere, ideally the switch. Too bad the switch is a couple of stud bays over.
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Jul 18, 2016 21:44
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kid sinister posted:That doesn't necessarily mean that you'd have to run more wires. I can think of 2 situations where you wouldn't need to run more wire: 1. you have one run of /3 into that box or 2. 2 runs of /2 into it. You'd have to pull that receptacle out and peek inside to verify. Not under a window, there's no basement (not even a crawlspace -- the floor is directly on concrete), and there's a second floor above; the kitchen is directly below the upstairs bathroom. And if I did want to rip open the wall of that bathroom, I'd also have to tear out the shower stall. Plus this house almost certainly doesn't use balloon framing so I'd have to drill through the plate between floors. Realistically, the house needs to be rewired at some point, but that's going to be so goddamn expensive and disruptive that I really don't want to deal with it. I haven't really mapped out all of the circuits but at least some of them are screwy (in the "someone tapped circuit A to add thing in room B that is otherwise on circuit C" sense), there's only 8 circuit breakers, and there's still knob-and-tube wiring in at least some parts of the house.
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Jul 18, 2016 22:16
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Here's the switched outlet. For an added bonus, it's on the circuit labeled (at the panel) as "Master Bedroom / 2nd Floor Outlet".   
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Jul 19, 2016 01:59
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kid sinister posted:Why is there a white wire on the ground screw? What is it attached to? quote:How many studs over is the switch from the outlet? I have to eyeball this a bit, but it looks like the switch is a little over 16" over from the outlet. I suppose if the studs were on 24" centers then they could be in the same bay, but it's most likely that there's one stud separating them. My usual technique for detecting studs, of running a rare earth magnet along the walls, doesn't work very well here because the wall is covered with tiles. Trying to detect stud spaces from the other side of the wall is tricky because the switch is located opposite a closet, while the other side of the wall the outlet is on (same wall on the kitchen side) is in a bathroom. I hadn't realized that before. On the plus side, I guess that means that if I need to take out any drywall in the closet area, the patch job doesn't need to be super good. On the minus side, the closet's kind of in the way.
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Jul 19, 2016 03:24
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kid sinister posted:In the old days, electricians used to ground boxes on the outside. Typically, they would run the ground wires back out their respective entrances, twist them together outside the box, then attach them to one of the gang screws on the outside. Do you have a circuit tester or multimeter? Re: grounding: oh, great. I would hope that they grounded to a pipe, since again the pipes are right there. I do have a multimeter, somewhere around here. I had a circuit tester but some mice decided to cohabit with it (it was stored in a small box on the floor of my garage). Maybe I can clean that up to the point I'm willing to try to use it. quote:You could buy a half inch flexibit, cut a hole in the wall a few studs over directly underneath the switch box, drill horizontally over to where the existing box is, then thread the wore through and patch the hole. It sounds like a lot, but that is the best solution I can think of for you. Noted. The horizontal distance is shorter than I'd thought it was, which makes the project seem a bit less intimidating. At least, I can conceive of horizontally fishing wire through one stud a lot easier than I can fishing it through, say, three.
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Jul 19, 2016 14:30
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kid sinister posted:You could buy a half inch flexibit, cut a hole in the wall a few studs over directly underneath the switch box, drill horizontally over to where the existing box is, then thread the wore through and patch the hole. It sounds like a lot, but that is the best solution I can think of for you. Following up on this, the basic procedure would be to open up the box containing the switch, pigtail some NMC to the "input" (always powered) side of the switch, feed said NMC down to where I've opened up the drywall, then feed it sideways through the drilled hole to the outlet. Hook the other ends of the NMC up to the receptacle I want to be always powered, while hooking the existing cable up to the receptacle I want to be switched. And while I'm down there, figure out if I have a cheating ground. Does that sound about right? If I do have a cheating ground, can I just attach the ground to the (metal) kitchen piping? I mean, if the ground is cheated, then it's probably cheated in other outlets throughout the house, and fixing that would be comparable to rewiring the house anyway: something that needs doing, but not something that I really feel up to tackling (both financially and in terms of stress it would add to my life) in the immediate moment. ...stupid homeownership. At least I already have everything I need (NMC, spare boxes if I need more room, wire nuts, drywall tools/patches/mud) except for the flexible drill bit.
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Jul 20, 2016 18:14
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kid sinister posted:It's just "NM". With that old cloth-insulated wire, I would honestly replace the run of cable with some 12-3. Use the black wire for always hot and red for the switched hot. The problem you will run into is that GFCI requirement for the dishwasher and that the duplex on GFCI outlets can't be split. Well, worst case I can install a second outlet next to the first one, and just have one switched outlet and one always-on. quote:A cheating ground is wiring the ground to the neutral wire. Still, one way electricians grounded steel boxes in the past was to attach the ground wires on the gang screws outside the box. Test for a circuit between the hot wire and the box itself. Noted re: testing ground. As for grounding to pipe, I understand that's not ideal, but given that I have a setup that's already not to code (for example, the kitchen shares a circuit with another room), I'm trying to figure out what the safest temporary solution would be (that doesn't involve just having no electricity at all) while I prepare to get the entire house rewired. Presumably a large chunk of metal pipe would make a better ground than a small metal box, right? I assume that the plumbing dates back to the 50's; certainly none of the pipes I've seen have been plastic. quote:Do you have an oscillating tool or a pocket hacksaw? They're great for removing original boxes out their existing holes in the wall. Basically, you pry on the stud side of the box a bit, stick your tool in the gap, cut through the 2 nails on the top and bottom holding the box to the stud, remove the clamps in the box holding the wires, then work the box out of the hole. I have an oscillating tool, yes. Thanks for the suggestion.
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Jul 20, 2016 19:15
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angryrobots posted:I recall reading something about cord- and-plug connected appliances cannot exceed 50% of branch circuit amp rating. Hm, in practice it wouldn't be an issue, since the dishwasher and garbage disposal are never really used at the same time (the disposal hardly ever gets used, in fact), but that's just because of my usage patterns and wouldn't necessarily hold for a hypothetical future owner. I have no idea what kind of amperage they draw. For that matter I don't know what the rating is on the circuit. Hashtag Banterzone posted:Couldn't you just use 1 GFCI and 2 regular outlets? If I can find an earlier outlet on the circuit I can just slap a GFCI on there and protect the entire thing. In that case I wouldn't need two outlets under the sink; I could have a single half-switched outlet. But then the question becomes determining what is upstream from the switch, given that we've already established that the circuits in this house are weird.
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Jul 20, 2016 20:19
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I guess what I could do is take existing input cable to the switch, disconnect it from the switch, connect it to the cable I run to power the dishwasher, and then use the neutral for the dishwasher as the new input to the switch? That way the switch would be downstream of the dishwasher -- that is, there'd be no branch in the circuit. Seems like a weird way to wire things up though.
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Jul 20, 2016 22:05
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