When working on your electric, might I suggest purchasing an Ugly's Handbook. It's more or less a simplified version of the NEC, (National Electtic Code) book. For quick reference of whether you're "doing it right". While I was considered a Master Electrician when I worked in the field, my Ugly's was always within easy reach.
I'll look out for one of those, thanks for the tip. I already have a reference card that covers a lot of the most likely code issues I'll face but it's always good to have a decent reference. Some things seem to be a matter of how you choose to do it rather than being specifically right or wrong though, and those are the things I'm trying to figure out how best to do to avoid filling my new breaker panel while also being at least somewhat futureproof. Another aspect with this house is that some aspects of code are more or less impossible to fully follow. Where code specifies the required depth of a back box but the back box of an approved size won't fit between the baseboard and the concerete wall it becomes a matter of figuring how well I can comply and which aspects are likely to be more critical. The theoretical options of chiseling sections out of my exterior wall, or restudding the entire house, aren't going to happen.... Since I can get at the basement space below this particular room without too much trouble I'm considering running a cable around the underside of the room with junction boxes, with each junction box containing a spur to feed a single socket. It's arguably not the most efficient way of doing it but does mean that if I do suddenly find I need a socket to be on its own circuit I can run a new cable to the junction box and just splice everything differently. That basement space is never going to end up as a finished living space (not least because it contains the oil tanks) so the junction boxes will always be physically accesible. It would also offer the benefit of meaning there was only one 3-core cable feeding each backbox rather than two, which would make everything a whole lot easier to work with.
And it's issues like that where the Ugly's comes in handy. Such as, how many 14ga wires will fit in a 4square box? It'll tell you handy little things such as, with each splice, each wire nut is considered a "wire" when calculating fill. And as far as running out of space in your panel. There are twin, or piggyback breakers. Essentially two breakers molded together that take up one slot in the panel. (You just have to pay attention to phasing your neutral (or common) wires.
That's the thing - code says how big a box I need based on how many wires, wire nuts etc I have but can't create more space than is already there. If code says I need a box three inches deep but I only have two inches available then something has to give - some aspect has to be compromised. In some cases I might be able to put a junction box in the basement space below the floor so I only need a single cable to the box but in other cases that might not be an option. I really struggle to understand why it's such a big deal to put two conductors under one screw. In the UK we've used junction boxes that work like that for decades and putting two wires under the same screw in our power sockets is just the way it's done. It also seems like a missed opportunity to save space in metal back boxes - given it's probably fairly standard to have a wire in and a wire out, I wonder why there don't seem to be metal back boxes with three tapped holes for grounding screws - one for the wire in, one for the wire out, and one for the wire to the switch or receptacle. At the very least it would make sense for receptacles to be designed so they had two green screws, just like they have two brass screws and two steel screws. If you've got two breakers in a single space (I've seen the tandem breakers, just never needed them before) how do you phase the neutral cables? Since both live wires would be on the same phase, wouldn't the neutrals also be on the same phase? I'd always assumed with those things you'd run a 12/2 or 14/2 to each of the breakers and each would have its own neutral?
One of the times you'll have an issue with your phasing is if you've ran three wire romex. (1black,1red, 1white, plus ground) as long as your black and red are breakered on different phases, they can share the one common neutral. If you attempt to run both black and red on a twin breaker (same phase) there's a very real problem with overloading the common wire. But yes, if you stick to only 14/2 or 12/2 romex (or mc cable) you'll not have a problem.
Another thought with a box too shallow, or not enough ci. Wiremold makes a nice surface extension box that can be one of two depths which can drastically increase your ci. (If you have the surface area for the outlet extending out of the wall.) Also, the issue of one wire under one screw. On the back of the newer outlets is holes that are "quick slip" connections. (The more expensive ones will sometimes have two holes) with these, you have the potential of putting three wires to the same terminal, eliminating the need to wirenut splice.
Ah, that makes sense. I knew about running 12/3 or 14/3 into two breakers and how it needs to be on a full-size double breaker for neutral phasing. Interestingly some of the wiring I took out from my house had a shared neutral on two breakers that were two spaces apart (and so, I believe, on the same phase). It's something of a miracle my house didn't burn down with some of the - er - interesting electrical work that had been done.
I don't want stuff standing proud of the wall. My receptacles are set into the wooden baseboard and I can't be dealing with boxes that stand proud from the baseboard. I didn't know about receptacles with multiple "quick slip" receptacles, I'll need to keep an eye out for those. The switches I've seen that let you insert a wire into the back of them only let you do that with 14-gauge, which is great for lighting circuits but doesn't seem so good for power circuits. If you can poke a 12-gauge core into a hole in the back of the receptacle that seems like it would make life much easier.
The switches (and outlets) that will only accept 14-ga. Are rated at 15amp. Which protects against overloading. You can rectify that by getting outlets (and switches) rated @ 20amp that'll accept 12ga wire.
One more of T's helpful hints and I'll leave you alone. When dealing with ground wires in a box with an outlet. Instead of wirenuts (which count as a wire) use an uninsulated crimp on sleeve, or barrel. Twist all your grounds together. Leaving two of them longer then the others. (One for outlet ground, one for box ground) slip your sleeve over the two longer grounds and unto the other grounds and crimp. The crimp on sleeve doesn't count as a wire. It also has the pass through capability the wire nut doesn't have. If you started out with three ground wires in your box, added two wires for box and outlet grounding, wire nuted them together, you've got a count of six ground wires in one box. Using the crimp on sleeve, you only have a count of three grounds. Bye Bye!
If you is holding a white whar in one hand and a black whar in the other, and you turn on the switch, if you git all warm and tingly, you got far.
Just remember. Every warning sign you see on every ladder, electric tool, and liquid in a Home Depot is there courtesy of your friendly neighborhood idiot.... ...and his lawyer.
The socket can be rated at 15A but if you've got two of them on the same circuit you could draw 10A through each, both would be within their ratings but the overall circuit would be drawing too much for 14ga wire, right? If you've got a 12ga cable that runs from junction box to junction box with 14ga spurs from each junction box to a 15A-rated receptacle you'd overcome the problem.
Probably more to do with the judge that awarded compensation in place of the simple message "that'll learn ya" than a lawyer.
By the way Tom, please don't think you need to leave me alone. I've picked up a lot of what I need to know, specifically where US code requires something that doesn't always make much sense to me, but it's never a bad thing to get tips and tricks from someone who has been there and done it before me. Whether it's some means of complying with code that I hadn't considered or even just an easier way to work it's good to learn new things.
A rule of thumb for your branch circuits. Try and keep a constant load at 75% or less of the amperage of the circuit. Say, on a 20a circuit, you'll want to keep the constant at 15a or less. According to code, you may use (I'll try and use your term of socket from now on rather than outlet), you may use 15a sockets on a 20a breaker. The screws on your socket, when used as line in/load out, is simply an external splice point and has nothing to do with the function of the socket. Therefore it's perfectly fine to use a 12g wire on a 15a rated socket. It's when you use the quick grip splice point on the back of the socket, the splice is encased in the socket, becoming a part of the device with the potential of overheating the device. Hence the need to reduce the wire size to 14g with the idea that feeding 14g wire through the socket, you'll naturally protect the wiring by having it come off a 15a circuit breaker. Now, I'm assuming that when you're running a 12g trunk line from box to box, it's a 20a circuit you're working with. So in theory, you're not overloading your socket by branching off with 14g wire, that 14g wire, no matter how short the distance, is not properly protected. So, according to code, in a 20a circuit, there can not be any wire, anywhere, less than 12g. (Including ground wire) So, go ahead and use your current wiring method. Just continue from your branch with 12g rather than reducing the wire size to 14g. Use the side screws. If you like the convenience of the quick slip on the back of the socket, upgrade the socket to 20a and the quick slip will accommodate 12g wire.
If it were my house and it was being built from the ground up, there would be nothing less than 20a circuits and 20a rated sockets throughout. The only thing allowed anywhere with 14g wire or less would be a heavy duty extension cord and wiring for table lamps and toasters.