Replies

1. 
   Cliff_Popejoy | Mar 02, 2002 07:08am | #1

   *
   Lam,

   Either 15A or 20A "general lighting" branch circuits are allowed by the NEC. These are the circuits that most of your "convenience outlets" are installed.

   Some juridictions have adopted and amended the NEC to require lighting outlets on separate circuits of 15A.

   I don't know whether there are places out there that require 20A receptacle outlet circuits, but I'd be very suprised if anyplace prohibited them.

   So, talk to your local building dept to be sure.

   Do you really want those "lazy-T" shaped neutral slots in your house?

   I once saw a house where the outlets were installed by the owner-builder, who had a little knowledge of electrical--very little. He insisted that all the branch circuits be wired w/12 gauge, protected with 20A breakers, and so he figured that ALL the outlets had to be 20A. The place had a funny industrial look to it...all those T-shaped slots. He also installed all the grounding conductor crimp sleeves by mashing them with a regular slip-joint plier, and had to go back and re-crimp every one with the proper crimping plier...

1. 
   George_Roberts | Mar 03, 2002 12:49am | #2

   *You can put 15 or 20 amp recepts on any branch circuit with a 20amp breaker.

1. 
   Mad_Dog | Mar 03, 2002 05:00am | #3

   *George,So what happens if you have a 15 amp receptacle and it takes on a 20 amp load? I'm sensing heat, fire, etc. Even worse, what if you do the same, and the thing has a loose connection...allowing some good amperage to flow before it trips the too large breaker?As much as I enjoy welding, this is not the place for it, is it?

1. 
   laminar-flow | Mar 03, 2002 06:27am | #4

   *OK, can a 15 amp circuit breaker be used with 12 gauge wire and a 20 amp receptacle? Or since the receptical can accept a 20 amp device, must the whole circuit be 20 amp, breaker and wire? It's no problem if it is, I'll put 20 amp breakers and 12 gauge wire in if it is OK with local building codes. I just got such a great price on these high quality outlets, I'd like to use them. Thansk for the help.

1. 
   Bill_Hartmann | Mar 03, 2002 07:40am | #5

   *MDIf you are doing it legally you would have to have a 20 amp plug for the 20 amp load. That won't fit into a 15 amp outlet.But the 20 amp recp will take either a 15 or 20 amp plug.For those that don't reconize the difference see http://www.quail.com/locator/nema.htmBTW, I have never seen anything with a 20 amp plug for household use.BillPS, I have not looked into this, but a friend of mine that is an electrican says that the guts of the qualify outlets are the same for the 15 and 20 amp outlets, but a different cover on it. I am talking about the $2-3 ones, not the 39 cent on sale for 29.

2. 
   Ralph_Wicklund | Mar 03, 2002 07:45am | #6

   *If you are going to use an actual 20A receptacle you should be using 12ga wire. Just in case someone ever finds an appliance that has the 20A plug configuation and plugs it in. You could, of course, then use the 20A breaker, since all bases are now covered. But you don't have to. 15A will be just fine. How many 20A plug in appliances do you see in anyones house?Regarding the difference between a 15A and 20A receptacle? Break one of each open (same comparative value) and you will find them to be identical, except for the face.

3. 
   Mad_Dog | Mar 03, 2002 05:46pm | #7

   *You're saying that you couldn't have an appliance (or power tool) that would draw more than fifteen amps with the right male end on it, and that alone allows this to break the code?

4. 
   Bill_Hartmann | Mar 03, 2002 07:40pm | #8

   *i You're saying that you couldn't have an appliance (or power tool) that would draw more than fifteen amps with the right male end on it, and that alone allows this to break the code? Technically no. The code does cover what is plugged in. If the state laws require it then it would be up to another group such as UL. For residencial I few if any require it. I believe that Canada is much stricter.Now my Jet contractors style saw motor is list as 18 amps and comes with a 15 amp plug. But the way that such a saw is typically use I have no concern about it. Now if I was constantly ripping 12/4 oak and had someone feed the stock and another person taking it off so that the saw was cutting continously then I would be concerned. That would put it in the continous use class which limits you to 80% load or 16 amps even on a 20 amp circuit. I would convert it to work on 240 in that case.

5. 
   George_Roberts | Mar 03, 2002 09:13pm | #9

   *it is amazing how this issue comes up so often and how many "stupid" questions are asked.Table 4202.13 in the 1998 ICC 1&2 Family Dwelling Code indicates the wire sizes, breakers, outlet ratings, and max loads on 15, 20, and 30 amp circuits.12 gage wire, 20amp breakers, 15 & 20 amp recepts and any type of lamp holder, and 20amp max loads for 20amp circuits.These components used together are safe because the code says so. Bill ---Your 18 amp saw does not draw 18 amps. The 18 amps is the draw when it stalls. The current rating for sales purposes may be 18 amps, but for UL approval the current is measured differently. This allows the use of a 15amp plug. I agree if you find you are loading the saw up a lot, change to 220 or put in a higher amp circuit.

6. 
   Jonathan_Bush | Mar 03, 2002 09:28pm | #10

   *The only places that 20a's make sense is along the kitchen counter top on an alterneting set of circuts,or in a shop.Do you want to spend the extra $ for 12ga wire and circut breakers just to use the outlets?jb

7. 
   Bill_Hartmann | Mar 03, 2002 11:04pm | #11

   *GeorgeThat 18 amps is the operating current when it is delivering 1.5 hp, NOT when it is stalled. Now this a basic imported motor and does not have full specs.Here is the spec on a Baldor that is roughly the same type of motor.http://www.baldor.com/products/perfdata.asp?1=1&page=1&catalogonly=1&catalog=CL3513&product=AC+Motors&family=General+Purpose%7Cvw%5FACMotors%5FGeneralPurpose&phase=1&hp=1%2E5&rpm=2800%2D3600&voltage=115%2F230&enclosure=TEFCNote that the currents are give for 240 connections in the table. I am converting it for 120 volt operation.At 100 rate load the motor draws 17.2 amps.At starting (and stalled) it draws 84 amps.

8. 
   Art_B. | Mar 04, 2002 03:46pm | #12

   *"I have never seen anything with a 20 amp plug for household use"Many of the higher end plug-in surge arrestors have 20 A plug configuration, and have seen 20 A plugs on home medical equipment. In locations where you want really high plug retention forces, the 20A work better because of the internal 90 deg set of contacts vs the flat blades on the T side (spec grade to spec grade comparisons, forget the 39 cent junk).

9. 
   Mad_Dog | Mar 04, 2002 05:36pm | #13

   *George, Bill,I guess I'm the one who's wrong here, at least in practical terms. This is helpful, because I noticed my brother's house had all 20 amp breakers, and 15 amp receps, and it was on my mind to tell him it was unsafe. Sorry to question your better electrical knowledge.MD

10. 
    John_Steinke | Mar 06, 2002 07:35am | #14

    *There seems to be some confusion here...The 'size' of a circuit is determined by the size of the overload protection. In other words, the size of the circuit breaker determines what must be placed downstream from it. The reasoning here is that you want components to be able to handle any faults that are too small to trip the breaker. SO- you can use any wire, #14 or larger, on a circuit protected by a 15 amp breaker. You can use any wire, #12 or larger, on a circuit protected by a 20 amp breaker. You are not allowed to use #14 wire anywhere in a 20-amp protected circuit- not for the last outlet, not for switch legs, nor anywhere else.This rule could be interpreted to forbid 15-amp rated outlets on a 20-amp circuit- so the NEC specifically allows their use with an "exception."Assuming that you have #12 wire on those 20-amp circuits, I see no reason not to use the 15/20 rated outlets. If you have #14 wire, get rid of those 20 amp breakers, and stick to 15 amp outlets.

11. 
    Brian_Smith | Mar 06, 2002 08:28am | #15

    *thank you, john :-)brian

12. 
    laminar-flow | Mar 06, 2002 05:17pm | #16

    *Thanks everyone for contributing to this question. After finally getting to talk to the local inspector, he said no problem in using a circuit with a 20 amp breaker, 12 gauge wire, 20 amp GFI outlet, and 20 amp outlets in house wiring. He did mention the new code to using arc fault in bedrooms.

13. 
    Rd | Mar 07, 2002 04:30am | #17

    *The small cost of 12 ga. wire and 20A breakers is worth the cost. In Chicago you have to have 15A breakers for lighting circuits. I found out the hard way. I rewired my house with 12 ga. wire and 20A breakers. The inspector made me change all of the lighting circuit breakers to 15A. He stated that the light fixture wiring is not designed for a 20A load. Oh well. I find that the 20A breakers let me plug my compressor or table saw into any outlet and not have to run to the basement to reset the breaker.

14. 
    George_Roberts | Mar 07, 2002 09:49am | #18

    *RD ---Just a comment on your inspection problems.There is no code requirement that forbids 20amp circuits for lights. The inspector was just wrong.Regardless of the local code, I always build to the ICC 1 & 2 Family Dwelling Code. There are two benefits to doing so. First, all of the code writing bodies accept it. So all of the experts are on my side. Second, the perscriptive methods in it supersede the individual codes. The local authorities can not bring in any other code.The fact that BOCA, an ICC participant, has a local office helps.

15. 
    Dave_Reichman | Mar 10, 2002 04:22am | #19

    *George, you must use a 20 amp receptacle if it is the only outlet on that circuit. If you have more than one, then either 15 or 20's are o.k. See 1999 NEC 210-21 (b).Dave R. Portland, OR

16. 
    George_Roberts | Mar 11, 2002 12:22am | #20

    *David you are certainly correct. If you use a single recept on a 20amp circuit that recept must be a 20amp recept. Last time I looked for a 20amp single recept I could not find one except the locking types. (Most recepts come 2 to a strap so installing a single is unusal.)I am sure you were making your comment in some context. I just have no idea as to what context.