electrical rough-in - another request for advice, etc

[Mia]

The electrical rough-in will be our next major undertaking.  So I'd better get busy & finish the detailed wiring diagrams.

Did most folks in this forum do their own wiring & their own diagrams for their homes?

We (by that, I mean my husband  ) have a little experience with wiring, such as adding a light to the garage & replacing a light switch.  But mostly we will learn as we go, as we have all along.  Our basic reference book is Black & Decker's, "The Complete Guide to Wiring," 2011 edition, the only book that I have bought new in years. We do have power to the house & to the large service panel in the basement.  And my husband has wired 3 or 4 outlets, included the dedicated circuit for the range & another to the hot water heater.

I don't have any specific questions at this time, just want to know if anyone can tell me how to minimize problems.  After all, I won't live long enough to make all the mistakes myself (especially wiring mistakes) so I have to learn from others' mistakes.

Thanks again.

[MountainDon]

I'm not familiar with that B&D book. Is it thorough enough to enable the reader / DIY'er to design systems that will meet the National Electrical Code, is the primary question? There are rules on the number of outlets / lights per circuit per wire size. Numbers of outlets and how they are divided for a kitchen is different from the rest of the house. It is not hard, but does require some study. In many places the homeowner is required to pass a test in order to do the job legally themselves. That is probably a good idea as it should help prevent some potentially fatal errors. An electrical error can easily kill someone faster than some framing errors. Neither are good but the electrical issues are more quickly lethal.   I've studied and passed the local electrical DIY tests three times in the past 20 years. The reference materials I used were bought at Lowes / Home Depot. Not the B&D book but a book that relates directly to the NEC. Sorry I don't remember the name. Available in any good electrical supplies section in the stores here. It doesn't tell you how to wire a three way switch like the B&D book likely does. But it advises on how many circuits, types of protection, etc etc. With that you can draw out your own system, submit the plan and get approved. or not.

[Mia]

This B & D book says that it is current with 2011 - 2013 electrical codes.  It doesn't cover every step from the service panel to running the cables & wires to the finished result.  (I haven't found a book that does.)  But it does have lots of photos & readable instructions & sample wiring diagrams & basic information.  I know we need a dedicated circuit for the water heater & for the range & for the dryer & for the microwave, etc.  I know where we must have GFCI receptacles.  Smoke detectors should be hard wired, in series, with battery back-ups.
Oh yeah, and I know that wearing rubber boots won't protect you from a shock if your hands are wet.  I learned that from an electric fence.   
I don't know if we can run the wiring thru the joists in the basement or if we're supposed to run it directly upstairs & then thru the walls (20 inches above the floor level) but I am going to ask that question of the county building department.

Thanks, Don.

[MushCreek]

You need to find out what NEC code you are required to meet, and then see if you can get a copy of it. Things are changing rapidly. I know that the version our area is under also requires Arc Fault circuits basically everywhere there is an outlet except outlets already covered by GFIC. Tamper-proof outlets are also required.

It isn't hard, but it is complicated (if that makes sense!) meaning that there are a lot of little things to consider. Interpreting the Code can be tricky as well, and your local inspector may have a different interpretation than one in another locale. For instance, it states that you must have at least one outlet 'at' a peninsula in a kitchen. At? Does that mean I could have one on the wall where the peninsula starts? To me, that meets the definition of 'at'. But the inspector might want an outlet 'on' the peninsula. There's no point in arguing semantics with an inspector (or anything else).

I'm not familiar with that book, either, but it sounds like a good go-with along with a copy of the current Code. The Code won't tell you HOW to do anything; only what is required.

[NM_Shooter]

Depending on the tolerance of your local building codes, you may be able to pull a permit to do this yourself.  As Don pointed out, you may have to take a test to qualify. 

One of the best electrical resources I had to help me pass the test was a spiral bound book, sort of a cliff notes version of the NEC that I bought at Home Depot.  I wish I could remember the title.  I'll see if I can look it up... there is a plumbing version of this too. 

Bottom line is that the electrical is probably the easiest part of the build.  You definitely have the skills to do this.  Get to be friends with the electrical inspector. 

Some of the gotchas are making sure that boxes and switches are at the right height, not overfilling boxes, ensuring that all wire splices are in an accessible box, and that your grounding is correct.  There are a lot of details, but this is not like framing.  If you make a mistake, you can easily fix it.

Good luck!

[davidj]

The B&D books are good books for showing the details of how stuff is done - great pictures.  The plumbing one helped me a lot.  But I'm not sure you'd be able to get enough info from them to work out all of the more obscure electrical code requirements though.  The "Code Check" books are the best way of doing that:

http://www.amazon.com/Code-Check-Electrical-Field-Wiring/dp/1561584088

They also do a general "Code Check" book, including a California-specific version.  I already had that but I bought the electrical one too as there really is a lot of detail and it's probably pushing it to do a whole house just from the general guide.

[NM_Shooter]

That was it!  Code Check.  Thanks!

[mfsangel]

For the efforts of full disclosure I am an electrical contractor so I can give you any advice you could possibly want regarding your electrical installation.

If you have any questions, let me know and I will answer them as best as I can.

Good luck,

Yours,

Roger

[MountainDon]

Thanks for that offer, mfsangel.

[archimedes]

Another thing you might want to consider.  Find an electrician to draw up the plan and answer any questions you have.  You drill all the holes,  run all the wires - you basically do all the physical work. 

A friend of mine hired an experienced electrician (who worked for a large local electrical contractor) who came by on his day off.  They paid him a few hundred $ but it saved them a lot of head scratching time.  From the electricians point of view he  didn't have to do any physical work on his day off.

[Mia]

Thank you for all the information & encouragement!  I will look for that code check book.
Electrical still seems way more complicated than framing.

A couple more questions - for outdoor lights, can we use the circuit in the closest room for an outdoor light?  That would be, back door light on laundry room circuit, front porch light on living room circuit, deck lights also on the living room circuit. 
And if we want a couple exterior outlets, I suppose they need to be GFCI & have weather-proof covers.  Can those outlets be on the closest interior circuit?  Maybe that depends on local code.

Hiring a professional to draw the diagrams is a great idea, we might do that.  But not right now - we will have our first electrical inspection on Monday, Nov 5th.  We are not ready, but it has been 180 days since our last inspection, so we can't put it off.  Probably should unplug & stow as many of the extension cords as possible, I kinda think the inspector wouldn't like to see how many extension cords we have running all over the place.

Other little problem is that we are running out of money.  So, once this inspection is done, even tho we know we will fail it, we have to clean out & clean up the house in town that we are living in. That will take some time & money!  Plan is to rent out that house & live in our '78 motorhome while we continue building our home.  We did live in a 24' motorhome for a year once, so it will be sorta like that.  But were in our 20's then, & didn't have so much stuff.  Now we are in our 60's & have a lot of stuff, & I have an office job, not a production job where I could where scruffy clothes to work.

Everything takes longer, & costs more, than you think it will.

[mfsangel]

Regarding your lighting that should not be a problem. A general rule of thumb is to look at your loads on a circuit when determining how much to put on it.

Lighting generally is very light as far as loads go. The way to figure out your loads is to take the wattage ratings and add them together. For instance, lets say you have three light bulbs running that are 60 watts each. Add them together and you get 180W. You can then divide them by the nominal voltage. In the United States lighting usually is 120V powered. So this math puts us at 1.5. This is the power in amperage so it is 1.5 amps.

So the simplest way is to see what is on your various circuits and therefore you can calculate the loads. If you have appliances they generally have a nameplate rating that will either be expressed in watts or amperage or both. So in the above example let's say you have a 1000W microwave, four can lights and a vent hood for the kitchen. You usually will see appliances with dedicated circuits but this is for an example.

So the can lights have four 65W bulbs (you will have to check your lighting loads). So 65Wx4=260W + 1000W for the microwave = 1,260W. Divide this by the nominal voltage and you come out with 10.5 amps.

Ohm's law allows you to reverse the math or just use basic algebra. So if you know the amperage and voltage you can solve for watts. Volts times the amperage=Wattage

So if the breaker rating is 15 amps (#14 wire) we can take that with the nominal voltage and solve for the maximum circuit wattage. 120V X 15 amps= 1800W. You can see that you would not want to exceed the wattage or the circuit will start to trip the breaker. The breakers are designed with a thermal metal strip that heats up as more power/amperage is applied. They are designed to spring open and throw the breaker handle after the thermal overheats. When it cools down again the breaker will be able to be reset.

Another example would be a 20A rated circuit. This would be #12 wiring and would consist of 20A times the voltage (120V) = 2400W. This is the maximum power available for this circuit.

So for instance you can easily run a 1000W microwave and a 1000W heater on the same 20A circuit (2000W is less than the 2400W rating). Also it is noteworthy to mention demand factors. If you never run items together, the maximum loads are not relevant since you will never go past the breaker rating.

The last factor to address is how the National Electrical Code addresses minimum code requirements. This can be found in Article 210 of the NEC (National Electrical Code).

The code has demand factors built in depending on occupancy.

Basically on a single family dwelling unit they have a volt-amps for square foot. Volt-amps=Watts. As in Volts X Amps = Watts as I showed above.

So dwelling units are 3VA or Watts per square foot. You take the square footage of your dwelling space. This usually excludes your garage since it is not considered living space.

So if your house was 1200 Square feet you would multiply that by 3VA to come up with 3,600VA. This is general lighting loads typically and most people wire this in #14 wire (15A rated wiring). As I showed above 15A x 120V = 1800W. So divide the 3600W by the 1800W per circuit to give you how many lighting circuits are required for your space (2 total).

The local AHJ (Authority Having Jurisdiction) can and does modify these requirements. The AHJ is really nothing more than the inspection body or inspector. I would recommend checking with them as to what requirements they have that are different from the NEC minimums.

For instance, San Diego has requirements that are more restrictive than the code with regard to how many outlets you can have on circuits etc (15 outlets for lighting and 4 or less for kitchens).

Outlets are defined as any device that utilizes power. So a light fixture or a receptacle outlet utilize power but a light switch does not so it would not be counted.

In addition to this the following are minimum guidelines:

Two 20A counter circuits for kitchens, one 20A circuit for the dining room outlets, one 20A circuit for laundry areas, a 15A dedicated circuit for the FAU (forced air unit/heater) and one 20A circuit for bathroom outlets. These are in addition to the two 15A circuits mentioned above for general purpose lighting.

You also might see dedicated power for heavy usage appliances like the dishwasher, microwave, refrigerator, garbage disposal, electric heater units or any other loads that require a lot more power like air conditioners etc.

The code is mainly in place for allowance to expand etc. Generally it is considered a good idea to size your wiring at no more than 80% of the anticipated loads. So on a 20A circuit you would want no more than 1,920W of load and for a 15A circuit you would want no more than 1,440W of load.

The last item to mention is AFCI circuit protection. Assuming you are pulling permits this may come into play. The requirement is that your bedroom outlets be AFCI protected.

Since this is a confusing item to most electricians, we have found that putting everything in the bedrooms on the AFCI breakers is the easiest way to meet this requirement. This also includes the smoke detectors in the bedroom and hallway. Since where we are they only allow no more than 15 devices on a 15a branch circuit you will need to balance the bedrooms and outlets v.s. this requirement and it might look like two or more circuits.

It is also useful to point out that if you are using a multi-wire branch circuit AFCI breaker protection will not be possible so in other words just stick with individual circuits for your loading.

Hope that helps out.

Yours,

Roger