Timeline for Can different gauges of wire be used on the same circuit?
Current License: CC BY-SA 3.0
14 events
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| Dec 12, 2017 at 22:33 | comment | added | Jim Stewart | @Mikey, is this house under construction subject to inspections by code enforcement or is this in a rural area with no building codes? If I had known at the beginning that the drywall was not up, I would have answered differently. (I assumed that this was a finished house and alterations to wiring would be much more troublesome, and I think everyone else thought so too). At this stage you can readily change to standard wiring practice. There are lots of changes in wiring practice and codes from the past. At this stage of construction it would behoove you to learn the current best practice. | |
| Dec 12, 2017 at 19:08 | comment | added | Harper - Reinstate Monica | This comment above is clearer and easier to follow than your answer. | |
| Dec 12, 2017 at 17:53 | comment | added | Jim Stewart | Wow, great that the drywall is not up! Any circuits that you want to be on a 20-A breaker MUST be entirely #12. (But it is OK to use #12 on a 15-a breaker and might even make sense if there is a long home run.) I think that most lighting circuits would only have to be 15-A in this day of the LED. I don't know if in modern houses only some receptacles need to be on 20-A circuits. In my 1970 tract house all the 120-V receptacles were in 15-A circuits, except for two in kitchen and dedicated ones for clothes washer and dish washer. | |
| Dec 12, 2017 at 17:41 | comment | added | Mikey | OK thanks glad I asked he was about to cover it up with drywall | |
| Dec 12, 2017 at 17:38 | comment | added | Mikey | Sorry from a 15a breaker to the first plug. He put 12-2 wire for home run. And from there to the other plugs he ran 14-2. The 12-2 wire is the hot to feed to the plugs. And the lights are on a 20a breaker. He done the same thing. Ran a 12-2 to the switch's box for a hot to feed them. And ran 14-2 out of the switch box to the lights. And fans | |
| Dec 12, 2017 at 17:33 | comment | added | Jim Stewart | But it is not OK to have #12 from a 20-A breaker to the 1st switch and then #14 going out to lights! You must change those breakers to 15-A. If the total draw on the lights trips a 15-A breaker, then you will have to put some of the lights on another circuit. | |
| Dec 12, 2017 at 17:22 | comment | added | Jim Stewart | It is OK to have #12 from a 15-A breaker to the first receptacle and then #14 from there on, but why would you do this? This would be unnecessary unless there were special circumstances such as a very long run to the first receptacle, but you say it is only 4 ft! Whatever the thinking was, you do not have to change out this #12 wire. | |
| Dec 12, 2017 at 16:33 | comment | added | longneck | @Mikey Can you put some periods in that comment? We can't understand what you are saying without some sentences. | |
| Dec 12, 2017 at 15:30 | comment | added | Mikey | All the plugs is on 15a breaker with about 4ft of 12-2 to the first plug and then to all the other plugs after that he ran 14-2 I didn't under stand it either it just need 14-2 for that first 4ft then and it's the same on the switch's 12-2 to the first switch and 14-2 going out the box to lights and he put them on a 20a breaker | |
| Dec 12, 2017 at 13:55 | comment | added | Tester101 | In the first case, the breaker should trip within a single cycle. In the second situation, the wire probably won't get hot enough to start a fire. The problem comes with the trip characterization of the circuit breaker, when responding to an overcurrent situation. A 20 ampere breaker can allow 30 amperes of current to flow, for up to 6 or 7 minutes before opening. 40 amperes can flow for 2 or so minutes, before the overcurrent protection kicks in. So the question becomes, how hot will the #14 get in 2 minutes with 40 amperes flowing through it? | |
| Dec 12, 2017 at 13:34 | comment | added | Jim Stewart | Another question is what happens if the 2nd receptacle is connected to the first by #14 and there is 8 A flowing through that section of #14 (from upstream loads) and someone plugs in a vacuum cleaner drawing 12 A into the 2nd receptacle? How hot will the #14 get in 5 or 10 minutes? | |
| Dec 12, 2017 at 11:51 | comment | added | Jim Stewart | Question for those knowledgeable about real world performance of power wiring: What would happen to the #14 sections of circuits with mixed #12 and #14 protected by a 20-A breaker in the event of a dead short in one of the #14 sections? Would the 20-A breaker trip so fast that no significant heating of the #14 would occur? | |
| Dec 12, 2017 at 11:09 | history | edited | Jim Stewart | CC BY-SA 3.0 |
added 63 characters in body
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| Dec 12, 2017 at 10:56 | history | answered | Jim Stewart | CC BY-SA 3.0 |