Replies

1. 
   BillHartmann | May 07, 2009 01:03am | #1

   Residential there is no limit on the number of receptacles on a circuit. But there are some limitation on laundry, bathroom, and kitchen circuits. But they don't limit the number, just the need for certain one and location.

   Some local code amendments do limit the number.

   The general requirement is that you have 3 watts per sq (IIRC the number correctly) for general purpose receptacles and lighting.

   For light fixtures you need to look at the wattage rating of the can or the fixture that would typically be used. But I would bump those up as they are often over lamped.

   For a circuit that is only used for receptacles 12 is often used as a rule of thumbs.

   But use some common sense. For example in a living room where you might only be using a couple of lamps and an occasional vacuum cleaner and you put receptacles very 3 ft, just so they are close to where ever you need them I would only count every 3rd one.

   And in some place like a high end home theater room with High Power audio and video systems, counter top microwave, counter top pop corn machine and small under counter refrigerator you could have everyting on one circuit by the code, if all of the fixed in place equipment is less than 10 amps each (refrigerator and maybe video projector), but common sense would be to split that up and have several circuits.

   .
   William the Geezer, the sequel to Billy the Kid - Shoe
1. 
   hardluckknocks | May 07, 2009 01:42am | #3

   Bill & Scott,Thanks. It's a non bathroom or kitchen circuit - and i'm way below the 12 outlets.Do either of you know where I'd find the code you mentioned? Do I have to buy a book or is it online somewhere?Is there a code about putting a stair lighting switch on the 'outside' 36" wall? I could put it under the last part of a 44" high window.

1. 
   excaliber32 | May 07, 2009 02:18am | #4

   Code does not say how many plugs per circuit. We usually put about ten. They cannot be more than twelve feet apart.

   For lighting, just don't go over 16A (amps) total, and you will be fine.

1. 
   DanH | May 07, 2009 02:35am | #5

   You should have lest than 16A on a 15A circuit.
   The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith

1. 
   BillHartmann | May 07, 2009 02:40am | #7

   The discussion specifically is about 20 amp circuits.But personally I don't like them for lighting. You often have small ceiling boxes and often have 3/4-way switches. In that case I think that #14 (15 amp circuit) is easier to handle. Also general purpose lighting in a home is not list at being Continous Loads so you can use the full circuit rating..
   William the Geezer, the sequel to Billy the Kid - Shoe

2. 
   rez | May 07, 2009 02:51am | #8

   Not code anywhere I believe but seem to recall recommendations that the fridge be on a home run.

    Is that factual? 

3. 
   BillHartmann | May 07, 2009 03:01am | #9

   The code clearly allows specifies that the refrigerator can be one of the kitchen small appliance circuits.But an other requirement is that any "fastened in place" plug and socket equipment not use over 50% of the circuit rating unless it is on a dedicated circuit. That is really meant for things like built in microwaves and DW. And many refigerators are constrained by water connection. And my their weight I feel that they are "fixed" in place, but not technically.The reason that none fixed in place equipment does not need dedicated circuits is that you never know where they are going to be plugged in. And that includes things like counter top MW's, space heaters and many heating type kitchen appliacnes.Probably an inspector would comment on using the a 15 amp refrigerator on the small appliance circuit and try and write it up. But could be sucessfully challenged, but then he might also pull every connect out of every box to see if they are long enough.In general, common practice is probably to have a separate circuit for anything above a low cost home where everything is done to minimums..
   William the Geezer, the sequel to Billy the Kid - Shoe

4. 
   oops | May 07, 2009 05:25am | #12

   This is a little off the subject but,

   It drives me nuts when I go to the power panel and try to figure out what each breaker protects what. It may the lights in one or more rooms or receptacle in one or more room or lights in one room and breakers in another and so on.

   The codes require that at each breaker it should be listed what it controls.It would take a book to properly list all of the various outlets for all of the breakers in some of the installations I have seen.

   Is it just too expensive to organize all this better? How do/would you wire your personal home. 

5. 
   Scott | May 07, 2009 06:47am | #14

   I agree that most electricians are pretty lame when it comes to labelling panels, and I'm surprised that there isn't a code rule that compels to a better job of it. It seems like an important safety issue to me.In my house (which I wired) I did my own label sheet. I've attached a copy.Scott.PS... if you're inclined, there are devices you can buy or maybe rent that help trace out circuits.

   
6. 
   CardiacPaul | May 10, 2009 05:45pm | #41

   Nice job on your list, I had to do the same thing after our house was done, sparky just didnt do it, took about 15-20 minutes & several trips up & down the stairs but well worth the effort No one should regard themselve as "God's gift to man." But rather a mere man whos gifts are from God.

7. 
   cap | May 11, 2009 01:48am | #42

   There are two main loads in a modern refrig, the compressor and the freezer heater coils (to keep the freezer frost-free).  I believe the heater coils run on a regular schedule, i.e., on for so many seconds every so often.  Any frost that's formed is sublimed off the freezer walls and ends up as condensate in the drip pan that we all never clean.

   I learned this the first time I used a recording voltmeter to measure current draw on a fridge.  I also was able to conclusively determine that the light bulb in the fridge DOES go out when you close the door!

   Cliff

8. 
   BillHartmann | May 11, 2009 04:38am | #43

   I don't have any proof of this, but I think that one of the big energy saving in energy star units is to not run the defrost and a regular schedule. Rather it monitors the frost build up and one runs it when needed. Also monitors as the frost melts and terminates the cycle as soon as it is cleared..
   William the Geezer, the sequel to Billy the Kid - Shoe

9. 
   BillHartmann | May 07, 2009 07:59am | #15

   I have not had to do a whole house.But I have mapped out about 5 or 6. And the worse is a place that has been remodeled or older homes with limited receptacles when built and more added.In a couple of case I drew a diagram with more details and put it in an envelope attached to the cover and just hit the main points on the schedule.But as Scott's showed sometimes it is more practical to cover several areas in one cirucit. Specially for lighting. And for lighting you have a larger number of scattered locations and places like halls and closets.And for receptacles when wiring one side of a wire it is more practical to wire the receptacles on the other side of that wall. So some rooms might be feed from the "left overs" for 2 to 4 different circuits.BTW, Scott is in Canada and I noticed some of this circuits would not be allowed by current NEC..
   William the Geezer, the sequel to Billy the Kid - Shoe

10. 
    Scott | May 07, 2009 05:10pm | #22

    >>>BTW, Scott is in Canada and I noticed some of this circuits would not be allowed by current NEC.Yes, electrical codes always seem like a moving target, especially when local ammendments need to be considered. For example, as DaveRicheson pointed out, I gave the "1440" number which is for 15A circuits. We aren't allowed 20A general purpose circuits.GFI in kitchens is another important difference, they go on and on....All the more reason to know the code, know your ammendments, know your inspector, and (try to) know what you're doing.....and have fun. Electrical work is the best.Scott.

11. 
    Junkman001 | May 07, 2009 05:10am | #11

    This is a 20 A circuit.

     

    MikeInsert initially amusing but ultimately annoying catch phrase here.

12. 
    excaliber32 | May 08, 2009 02:12am | #29

    12A max for a 15A lighting circuit.

2. 
   BillHartmann | May 07, 2009 02:36am | #6

   You are suppose to be able to view a free version of the NEC on the national fire protection website ( nfpa.org I THINK). But it is tricky to find and the last time I tried to use it would not work the java on my system.As the NEC says it is not a design guide. So it does not get into many of the details that you are asking about.For example the the only limitation of the height of receptacles is that they be reachable and I belief that is under 5 ft.And I know that for stairs of certain lenght that switches are needed at the top and bottom. But I believe, but not sure, that is gives any details about where the switches need to be..
   William the Geezer, the sequel to Billy the Kid - Shoe

1. 
   hardluckknocks | May 07, 2009 05:36am | #13

   thanks for all the great info!

2. 
   jonblakemore | May 07, 2009 08:50am | #16

   "You are suppose to be able to view a free version of the NEC on the national fire protection website ( nfpa.org I THINK)."

   Bill, this interests me because I have all of the other I codes on .pdf format, but no NEC. That can be a pain sometimes.

   I did find the full (as far as I can see) NEC here.

   http://www.nfpa.org/freecodes/free_access_document.asp?id=7008SB 

   Jon Blakemore RappahannockINC.com Fredericksburg, VA

3. 
   Scott | May 07, 2009 05:04am | #10

   >>>Do either of you know where I'd find the code you mentioned?Last time I needed a copy I found it at the public library. Around here, if you want to buy it it's around $200. No thanks....Scott.

1. 
   DaveRicheson | May 07, 2009 01:22pm | #17

    Around here, if you want to buy it it's around $200. No thanks....

   That is nuts.

   I got the 08 NEC for less than $80, maybe at as low as $60, from my electric supply house. I can order the handbook for about $90 IIRC.

   You can order it here:  http://www.constructionbook.com/nec-code-2008/ for $82.50.

   Someone is jerking your chain.

4. 
   joeh | May 07, 2009 05:06pm | #21

   http://bulk.resource.org/codes.gov/

   Free downloads.

   Joe H

1. 
   MikeHennessy | May 07, 2009 06:39pm | #23

   Hey -- that's a great resource. Never saw it before. Thanks!Mike HennessyPittsburgh, PAEverything fits, until you put glue on it.

2. 
   hardluckknocks | May 14, 2009 06:38pm | #44

   thanks. pretty nifty.

2. 
   JHOLE | May 07, 2009 02:34pm | #19

   Iwas curious what your thoughts were on this;

   http://www.co.lucas.oh.us/DocumentView.aspx?DID=841&DL=1

   If that link works - it is our county building departments "wattage schedule". I am not an electrician, but have, and do a good amount of electric. I have used this as a guide for years. I would be interested in your thoughts on it...Remodeling Contractor just on the other side of the Glass City

1. 
   BillHartmann | May 07, 2009 04:21pm | #20

   At first I thought that it was OK. But them started to look at it in detail and don't like it.Now it might be OK to use as a non-enforceable guideline. But I can see it as a requirement.And I don't think that it is right in the some of the details. But probably somewhat outdated. One of the biggest that I see is the refrigerator. Even with Energy Star a modern 21-25 sq ft refg is going to draw about 8 - 10 amps. And they run almost continously.And I think some of the others are low also, but diversity will handle those.The lighting is a good start and reasonable in most cases. But they restrict you to 15 amp circuits on lighting. While that is what I prefer, just for handling the wire and box fill, I don't see any reason to limit the circuit to that by code.And I did not see can lights and 150 VA is what to much to use for them. Except for a few special ones the would literally metal with a bulb that big.And in some cases the wattage for bathroom lights is too small. And I wonder how they count receptacles. By code the common duplex receptacle is TWO. And I am looking at the kitchen counter top numbers. And you might put in some plug mold for convience, which can increase the receptacle count and using their number require extra circuits, but you still have the same counter top space and the same under of appliances and the same number of cooks.So again I would use common sense about how big the space is and how it is used to see if I wanted to use more than the required 2 small appliance circuits.If you look up in FHB magazine Extras, there is a worksheet from the NEC that shows how to calculate the service size for the whole house. But other than the required specialized circuits if does not give you any help in breaking it down to the number of circuits.
   .
   William the Geezer, the sequel to Billy the Kid - Shoe

1. 
   xxPaulCPxx | May 07, 2009 07:37pm | #24

   Even with Energy Star a modern 21-25 sq ft refg is going to draw about 8 - 10 amps. And they run almost continously.

   WHAT? 

   I've got a kill-a-watt on my refrigerator now, it's energy star, but IIRC it was on the far end (less efficient) side of the scale.  It's got a door on the front for milk and juice, something I don't see on others anymore, as well as an icemaker.

   At the moment, it's drawing .03 amps, or 3 watts.  It's been doing that for the last 5 minutes.  I'm going to go open both doors now to see what it ramps up to.

   Tu stultus esRebuilding my home in Cypress, CAAlso a CRX fanatic!

   Look, just send me to my drawer.  This whole talking-to-you thing is like double punishment.

2. 
   xxPaulCPxx | May 07, 2009 07:43pm | #25

   OK, I left the doors open for a couple minutes and the compressor is now on.  I went and checked the kill-a-watt again.  While the compressor read 3.50 amps for a few seconds, it was dropping the moment I closed the doors and leveled of at about 2 amps.

   This fridge is about 8 years old now.

   Tu stultus esRebuilding my home in Cypress, CAAlso a CRX fanatic!

   Look, just send me to my drawer.  This whole talking-to-you thing is like double punishment.

1. 
   BillHartmann | May 07, 2009 08:11pm | #26

   I suspect that you all you measured is one (or more) of the fans.I have an energy star rated side by side and the label current is 11.2 amps.But you hear it make several different noises and combinations of noise. Best that I can figure by listening to it and looking a parts break down is that that there is a solenoid air valve between the freeze and the refrigerator compartment. And thermistors that measure the temp in each compartment and the on the refrigeration coil for monitoring frost and defrost. And maybe one on the compressor.And a fan that moves air between the freezer and fridge. Do depending on the need in each compartment at the time you might have just the valve open, the valve and fan, all without the compressor running. And other times with the compressor running.And instead of just having a fan on the compressor coils that run when the compressor runs it monitors the temp and does not run the fan until it is needed..
   William the Geezer, the sequel to Billy the Kid - Shoe

2. 
   xxPaulCPxx | May 07, 2009 09:38pm | #27

   I just left the freezer door and fridge door open for 5 minutes (stopwatch) AND had a fan blowing in room temprature air the whole time, and it still only drew 3.5 amps... 1.5 of those were the lights on the inside.  The fan was running, it was using 2 amps.  I closed the door and the compressor still didn't kick on.

   I unplugged it and opened the doors and let it sit a minute, then plugged it back in again.  It briefly went to 11 then 13 amps, before settling back down to 2 amps again.

   As I type this, now after nearly 10 minutes of warm air invading the insides, it's currently drawing .3 amps now that it's sealed up again.

   I have a hard time seeing how this fridge could possible be drawing 8-10 amps all the time.  Occasionally - like when the kids come home or you are prepping for a big party, maybe for a few moments.  But it is certainly not sucking down that amount of juice 360/24/7.

   Tu stultus esRebuilding my home in Cypress, CAAlso a CRX fanatic!

   Look, just send me to my drawer.  This whole talking-to-you thing is like double punishment.

3. 
   Scott | May 08, 2009 07:31am | #30

   If you listen *really* carefully you should be able to hear the compressor cycling on. Like Bill says, there is often a fan that simply moves cold air from the freezer to the fridge. Also, there may be a door switch that stops the compressor from running with the door open, which may explain your situation.I find it hard to believe that a refrigeration circuit could be operated on 3 amps. If you find it is so, please pass on the make/model 'cause I'd like to buy one!!!Scott.

4. 
   xxPaulCPxx | May 08, 2009 09:18am | #31

   OK, I just zeroed the Kill-a-watt meter.  In 24 hours from now, we will have a reading of how many kilowatt hours this unit uses in 24 hours.  We can extrapolate that over the course of a year.

   Any guesses how many my fridge will use in 24 hours?

   Tu stultus esRebuilding my home in Cypress, CAAlso a CRX fanatic!

   Look, just send me to my drawer.  This whole talking-to-you thing is like double punishment.

5. 
   xxPaulCPxx | May 08, 2009 09:18am | #32

   OK, I just zeroed the Kill-a-watt meter.  In 24 hours from now, we will have a reading of how many kilowatt hours this unit uses in 24 hours.  We can extrapolate that over the course of a year.

   Any guesses how many my fridge will use in 24 hours?

   Tu stultus esRebuilding my home in Cypress, CAAlso a CRX fanatic!

   Look, just send me to my drawer.  This whole talking-to-you thing is like double punishment.

6. 
   BillHartmann | May 08, 2009 03:43pm | #33

   You never did indicate what the nameplate rating is.I am going to use 12 amps. That would give you a max of 288 watt hours if it ran continuously, which it won't.Now modern Energy Star refrigerators the compressors are "sized right" and run a long time. So the guess is on what percentage of time that it runs.But it has to be able to keep up in 100 degree, 95% humidity.Now your kids are still on the small size and still in school so they won't be keeping the door open for 10 minutes at a time looking to see what there is snack on between the last snack and the one an hour later.And I am guessing that the weather is mild and also it won't have to do a defrost cycle often. So I am guessing a 25% duty cycle or 8640 whr..
   William the Geezer, the sequel to Billy the Kid - Shoe

   Edited 5/8/2009 12:12 pm by BillHartmann

7. 
   xxPaulCPxx | May 09, 2009 11:06pm | #36

   OK, Just checked the Kill a watt

   From 11PM on the 7th to 1PM on the 9th = 38 hours time elapsed

   KWH= 5.49 

   Or .144 KWH per hour x24 hours = 3.467 KWH

   Tu stultus esRebuilding my home in Cypress, CAAlso a CRX fanatic!

   Look, just send me to my drawer.  This whole talking-to-you thing is like double punishment.

8. 
   Scott | May 08, 2009 05:39pm | #34

   re: the kids.Bill clearly knows more about your family life than I. Sheesh, is there anything that guy doesn't know? A bit scary..... ;)But I digress. I'm going to guess a bit lower. I'll go with approx. 8 amps running at about 20% duty which puts it around 4.6 KWH in 24 hours.Scott.

9. 
   BillHartmann | May 08, 2009 07:17pm | #35

   After seeing your numbers I realized that I forgot to multiply by 120 (volts). Shouldn't post before my first coffee.Paul posted a thread with pictures of "living dinosaur" that he made for his kid birthday party.Don't remember how many kids that he had and which where his, but IIRC they looked around 6-8 yo..
   William the Geezer, the sequel to Billy the Kid - Shoe

10. 
    xxPaulCPxx | May 09, 2009 11:09pm | #37

    Well, you were closer:

    3.467 KWH over 24hrs

    BTW, it was 11.6 amps on the lable.

    Tu stultus esRebuilding my home in Cypress, CAAlso a CRX fanatic!

    Look, just send me to my drawer.  This whole talking-to-you thing is like double punishment.

11. 
    BillHartmann | May 09, 2009 11:17pm | #38

    "BTW, it was 11.6 amps on the lable."But you need to size the wire for that current, not the average load.But the NEC does take that into account and other things for the sizing the service for the whole house..
    William the Geezer, the sequel to Billy the Kid - Shoe

12. 
    xxPaulCPxx | May 10, 2009 09:51am | #40

    It was less a question about about the amps it used, and more a question about how much it used for how long.  But that was fun to do!

    Tu stultus esRebuilding my home in Cypress, CAAlso a CRX fanatic!

    Look, just send me to my drawer.  This whole talking-to-you thing is like double punishment.

13. 
    Scott | May 09, 2009 11:55pm | #39

    Interesting experiment. I'll have to get one of those watt-meters.Scott.

3. 
   JHOLE | May 08, 2009 01:12am | #28

   Thanks, just did a cursory reading and will delve into it later - could have some follow up questions. I appreciate your review.Remodeling Contractor just on the other side of the Glass City

2. 
   Scott | May 07, 2009 01:06am | #2

   Like Bill says, local amendments may vary in your area. Around here it's a hard-and-fast limit of 12 receptacles. If the circuit is for lights only then it's by a wattage calc (no more than 1440 IIRC).

   Scott.

1. 
   DaveRicheson | May 07, 2009 02:12pm | #18

   1440 watts is the 80% mark for 15 amp circuites. 1920 watts is the 80% load for a 20 amp circuite.

    He was asking for information on a 20 amp run.

   Edited 5/7/2009 7:14 am ET by DaveRicheson