Putting in new electrical circuits and outlets

Lutron makes good dimmer products, including three-way switches. They have detailed instructions included, and they are very expensive. the last one I installed was over $40. When you get into things like, this that have internal electronics, it's important to get it right the first time. Many devices like motion sensors, and dimmers will self destruct if wired wrong, or wired into a hot circuit. Good luck.

Here is a link that will help you out. www.k3ahformulas/e_drop.htm
Or if that dosen't work try a google search for "wire size formula"
Enjoy the day!!!!!

If you decide to do voltage drop calculations based on simplified methods, or quick calculators found on the net, please find a few techniques and try to find agreement with the results of a few. The reason I say this is that there is at least one available on-line sizing tool that is totally off the wall. It will grossly oversize the wire. This may not be an issue if wire was free, but it has gone from being costly to horribly expensive. On a job like running an underground feed to a sub-panel in a distant outbuilding, oversized conductors could add a couple of hundred dollars of wasted cash to the job. For instance, on another thread, a poster tried to claim that it would be better to ignore my recommendation and switch to the next bigger size of UF cable to supply a few outlets in a shed. This bit of advice would run about $110 more, and isn't necessary. The days of Romex costing $15 a roll are gone, you really have to be careful with not wasting wire, or over-engineering the job.

Some people feel better with 3% voltage drop to electric motors, and assume there will be another 50 feet or so of internal wiring.

Some don't mind a 5% drop with dimming lights & shorter motor life.

My place went from #8 copper overhead going 400+ feet to 'just get by' - to now having underground al wire measured with Roman numerals to size it.

That 'just getting by' wasn't so fun, a $110 investment today can pay a big dividend 10 years from now.

Two different ways of looking at things, is all.

--->Paul

Not to be a jerk or anything but I own a gas powered weed eater so no need for an extension cord.

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It can be done at both switches but not by wiring. These critters talk to each other but it just replace one switch with the other.

http://www.smarthome.com/2494m3.html

Couple of things to think about here. five percent is within acceptable design values and will not result in dimming lights or shorter life of anything. My point with just grabbing a calculator off the net, is that some can be downright silly, recommending wire sizes that are far in excess of what is truely required. Last, when somebody is heading to a fairly close outbuilding, and wanting to run a receptacle and a few lamps, $110 spent on needlessly oversized wire, is not an investment, it is a waste of cash. If the building is sixty feet away, and it's getting fed from a single 20 amp breaker, throwing extra copper in the ditch is a waste. If the material is laying in the barn, no problem, but I don't think most folks are aware of where some of the prices have headed in the last two years. Electrical wire is literally four times the cost it was two years ago.

I don't disagree with you.

The one thing I see, is folks going through the expense of digging a trench, doing some wireing, spending some time, buying some copper, and have a 'barn' where they want just 'a few tools'. Then they start talking about a 110 welder, but only for 'light use'.....

At that point, one is being too darn cheap on the copper..... Put in a good, 60 amp service. One is fooling oneself to think some 10 ga wire running 100 feet to a 20 amp breaker is going to meet the needs one will have. That is being too cheap & limiting. One will either be disappointed & compromised for decades, or will have to throw away all their work & redo it in 5 years when things are even more expensive.

That's a mistake most of us have made I'm sure, & some of us will point that out.

Wiring costs what it costs, we can't turn the clock back. Have to look at our options, and make good decisions on where we want to be a decade from now.

I understand your point, & don't disagree, but people sometimes get tunnel vision on saving $110, and end up severely limiting themselves. That's a bad thing to do too.

--->Paul

NEVER NEVER NEVER-did I say never? Do not take shortcuts with electrical wiring or size to save a little bit. Good way to burn your home down, ruin electrical engines, and have constant trouble. Spend the extra FRNs and do it right the first time. Electrical systems are not the place to save a few dollars. And for small jobs-do it and call no one. Just do it right. If I had a metal box I would take it out and use a plastic one if going through it to the outside.

Theres a old saying....

There are old electricians and bold electricians, but no old-bold electricians.

Do your homework, read, read and read some more, ALWAYS put in lower gauge wire than you need, if you need 14 gauge, think about putting in 12!

You must understand how the electrical service to your house works, you must know what ALL the wires are and why there are there, and what they do.

Until you open your electrical panel, and know what every wire does, think about reading more, getting more advice, or even hiring someone else to do it.

IF you hire someone, make teaching you a condition of hiring them, ask lots of questions and LEARN from spending the money.

House wiring is simple, but it can kill you, or burn your house down, if your not sure, DO NOT GUESS, you MUST KNOW FOR SURE what you are doing.

Sorry to be a wet blanket, but I know this stuff, and while its great to learn and do it yourself (thats how I learned), you really must not skimp or try to 'save money' on wiring or electrical.

Thanks. Remember I live in a suburb, so there's no room for outbuildings here. All my wiring projects will be in-house. There's only about 26 feet between the back of my house and the back fence, after all, and 6 feet to the fence on either side.

But since I'm in California the market value is well over $500K (no, I didn't pay that, I bought here 20 years ago when this was the sticks and cheap--if it weren't for prop 13 I'd have been unhoused by taxes). So it is worth doing the job right, which is why I want to add an extra 20 amp breaker to put the tool/fountain outlet on the house front--the wiring distance isn't that far (I bought 100 feet and now have revised my plans to put only one outlet up, which means I'll need only about 25 feet, but from the sound of it and the cost of copper the remainder of the Romex will probably be a good investment for future years). I'd rather do it this way--the complicated but 'right' way--than just put a box outside back to back with an inside box. I get the gauges mixed up but I bought the thicker of 12 or 14 gauge, interior Romex, designed to handle 20 amp circuits (plugs) rather than 15 amp ones (lights).

To the "experts" in posts # 29 & 30, please actually read and comprehend what I have written, before you make statements that are totally false. Nobody is advocating undersizing anything. There is no reason to spread misinformation like a wire size, properly selected for the load, will ever burn a house down, ruin electrical MOTORS (there is no such thing as an electrical engine) or create constant problems. There are literally billions of installations that prove that everything you claim is false, and based on a complete lack of knowledge. The second post has an equally silly claim about always oversizing conductors. Really? There is absolutely no reason to just randomly oversize conductors in any application, it is a waste of time, resources, and most importantly money. I'll say it again for those that actually read and comprehend things. Copper wire, in the last few months, has been 4-500% higher than historical averages. If you chose to waste money based on a lack of understanding and research, feel free. Most of us don't really have a lot of extra cash to throw away needlessly. There is a lot of good information available both on and off line. If you are serious about doing a safe and rational electrical installation. Forums like this are a great place to avoid. There tends to be a small minority of helpful, knowledgable tradesmen and others involved, and many clueless "experts" who are best ignored.

Tioga, my book on wiring says 14 gauge for 15 amp circuits, for ceiling lights, and 12 gauge for 20 amp circuits, for outlets. It also talks about how to take an inventory of the load on a circuit to decide if larger options are needed.

In my case, I'm thinking about adding switches on existing lights, maybe adding an indoor sconce light or two, and adding an additional outlet on the house for common electric yard tools in the front yard or maybe a small pre-fab patio fountain. So I think these rules of thumb will be sufficient; I'm not adding a detached garage or a barn-addition or wood/metalshop. Just little stuff.

Thanks for looking out for me.