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-   -   Is this normal? 20A circuit 20A wires feed 15A wires (http://www.diychatroom.com/f18/normal-20a-circuit-20a-wires-feed-15a-wires-63734/)

walt1122 02-05-2010 10:08 PM

Is this normal? 20A circuit 20A wires feed 15A wires
 
Hi, didn't think you were supposed to do it this way so I'm asking if what I see is correct. New house, new electric. I'm adding a 4 way switch inbetween two 3 ways so I can have an additional switch in garage to turn the lights on or off. Wires appear to be 14 guage 15A? Bare wire diameter is .60+- Already have enough holes so didn't way to add this additional one just to confirm that the wire also SAYS 14 guage on the sheathing. But the wires at the box are 12 guage 20A .80+- fed by a 20A breaker. I may be wrong about this but I always thought if you start with 12 guage you stay with 12 guage? Am I misunderstanding this and it is OK to have smaller guage wires fed from larger guage wires.

thanks

Walt

Scuba_Dave 02-05-2010 10:10 PM

Smaller gauge is not OK
A 20a circuit must have 12g wire
If you have verified that breaker controls these lights then you need to install a 15a breaker

vsheetz 02-05-2010 10:19 PM

20a #12 lighting circuit - switch loops and travelers can be #14, can't they?

Billy_Bob 02-05-2010 11:08 PM

Quote:

Originally Posted by vsheetz (Post 395471)
20a #12 lighting circuit - switch loops and travelers can be #14, can't they?

Here is the official answer to that...
http://www.inspectorsjournal.com/For...TOPIC_ID=10538

Scuba_Dave 02-05-2010 11:21 PM

So, the answer is no, not allowed
The 15a switch can only control 15a of lights
That does not mean the conductors can be 14g

If you have 20a of lights on a 20a circuit & use only 1 switch to turn them off & on then that switch would be required to be a 20a switch

walt1122 02-05-2010 11:44 PM

live and learn!!!
Always wondered about the use of 15A switches in 20A circuits now I see that this CAN be an acceptable practice so long as you know you won't be able to overload! And based on the link I can feel OK about the 15A wires feeding the lights from a 20A circuit. However, if I were to redo all this I would certainly use 12 guage and spring the few extra bucks to put in 20A switches. I have done it this way for years in my own homes and yes if I were doing it for a living and had to bid on jobs I guess I would follow this procedure. Sound OK in principle just had me scratching my head.

thanks all for the help and for making this more understandable. I have more work to do, replace a hidden splice box in the duct chase, and I want to add a Sub Panel so I'm sure I will be back with more questions.

Thanks Again

Walt

walt1122 02-05-2010 11:50 PM

wait I think I'm still confused. I just reread the link and SCUBA_DAVE I think I see what you are saying. A 15A switch can be used on a 20A circuit only if the load is less than 15A BUT the wire MUST be 20A.

Scuba_Dave 02-06-2010 10:01 AM

Quote:

Originally Posted by walt1122 (Post 395497)
wait I think I'm still confused. I just reread the link and SCUBA_DAVE I think I see what you are saying. A 15A switch can be used on a 20A circuit only if the load is less than 15A BUT the wire MUST be 20A.

That is correct, in most instances a switch in a residential setting is not controlling anywhere near 15a (1800w)

The 15a wire is not OK since it is part of the branch circuits
Branch circuit wire can't be lower then what the breaker rating

walt1122 02-06-2010 11:25 AM

Thanks Scuba_Dave, could this have been acceptable in the past? The home is in Tennessee and I had a full electrical inspection and was approved even though I have found two 20A circuits with three way switches set up with 15A wire as the run between the switches. The inspector has a reputation for being tough. He had the electrician use only a 25A breaker and fuses for the 10A wire supplying the 30 gallon hot water. Said a 30A circuit breaker wasn't proper protection? So it is hard to believe he didn't catch the 14 gauge wire where 12 should be used. Did Code allow for the use of 14 gauge in the past. Are all parts of the country on the same Code page or could this area still be on some earlier version??
I ask this because of what vsheetz had said "20a #12 lighting circuit - switch loops and travelers can be #14, can't they?" Not to pick on him but he must have heard this from somewhere??

Billy_Bob, thanks for the link, is there one that talks more about the wire size. This one is great for the switch discussion and does talk about the wire size but I wonder if there are others


thanks

Walt

HouseHelper 02-06-2010 11:49 AM

I have seen the 14ga wire used for switch loops and 3way before on 20A circuits, but always in much older houses (40+ years old). It is NOT a code compliant way to wire, and if it exists in a new structure, the electrician should be held accountable.

As for a 30A breaker not being compliant on a #10ga circuit for a water heater, that is completely bogus.

Scuba_Dave 02-06-2010 11:50 AM

I'm not sure if this was ever legal in the past
Need someone with knowledge of older codes
I "know" Jeff" (person in the link) from another site, I have read a lot of his posts
I trust his knowledge & information to be correct
If it was legal in the recent past (NEC 2005) I would think he would mention it

Is this a new house & new wiring that was passing Inspection ?
Or just a home Inspection prior to purchase ?
How old is the house ?

A 30a breaker is allowed on a circuit with #10 wire unless it runs a long distance (100'+ maybe)
Then the breaker might be undersized to allow for voltage drop, IF the load is actually lower then 30a
But usually the wire is oversized to correct this, not a smaller breaker

Local codes can vary, but never heard of anyone restricting #10 to 25a

Billy_Bob 02-06-2010 12:44 PM

Quote:

Originally Posted by walt1122 (Post 395625)
Billy_Bob, thanks for the link, is there one that talks more about the wire size. This one is great for the switch discussion and does talk about the wire size but I wonder if there are others

There is plenty of discussion about this on the internet - what people say they *do* - what their opinion is. (And what they do / what their opinion is may not be correct!)

So that is the good value of that link above, it is an "official" answer (the first post there only).

But if you want to read a lot of discussion (arguing :)) about these topics, might want to poke around here (especially NEC section)...
(Note: Not a DIY site, please don't ask DIY questions.)
http://forums.mikeholt.com

Then following is a google filtered search of ecmweb.com (Electrical Construction & Maintenance magazine). It searches just that link for the term NEC. They have some really good articles there...

http://www.google.com/search?hl=en&a..._nhi=&safe=off

walt1122 02-06-2010 01:46 PM

thanks guys. Guess I have some work to do. Will just replace the 20A circuit breakers with 15A's for now. Will have to see how much draw is on each of the two lines so I can determine if new home runs will be required to take some of the load off of them. I did tell the builder to leave plenty of capacity on each line just in case I wanted to add to them but if they can't even follow code then who knows what they did.

Scuba_Dave, brand new house. Three car garage (28 x 34) with an apartment above. Has 200A service ( I wanted 400A but they ran wrong wire from transformer underground and wanted ME to pay for replacing it). The main house was supposed to be built in the future and I would share the 400A via a tap from here to feed the house.

Thanks Billy_Bob, I'm not looking for shortcuts or peoples interpertations. Just want to be sure of the facts before I act in haste and don't have all the facts correctly. I'm thinking of going after the builder thru legal means. He has made mistackes with foundation, structure, plumbing, electric, septic, HVAC and even water ( buried the water line 6 inches deep here in the mountains of tenn. He found rock, sandstone, that he didn't want to cut thru so he just stopped and buried it over. I was working around house and found it and had to jackhammer down to 14 inches before I gave up. He was on cost plus so what did he care? I was paying for him and he got a cut!!)

the only good thing!! We didn't hire him to do the main house!!!!!

Walt

Billy_Bob 02-06-2010 02:14 PM

Be aware that things don't always get copied exactly right!

And in my state, they "adopt" the NEC of a given year like 2008, AND amend it in a few places, then place the amended text into the "official law".

Some states have not yet adopted the 2008 NEC for example.

In other words, get the NEC text straight from your states law books or whatever, and be sure that wording was in effect at the time the house was built. (Also check with your local electrical inspectors.)

For example according to the following, some islands in Hawaii are still going by the 1993 NEC! But I would not go by that web page, rather by checking the laws for those specific islands.

http://www.nema.org/stds/fieldreps/N.../implement.cfm

The same NEC rule will change from time to time. So very important what the exact wording was for your state/county/city[island :)] at the time your house was built and if there were any local amendments.

walt1122 02-06-2010 03:44 PM

Thank You Billy_Bob, that is exactly what I was wondering. From the excel list it shows some parts of Tennessee are still using 2002 NEC codes. So if they had in addition to the older NEC Codes some admendments like allowing the use of the 14 gauge in the 20A circuit breaker protected circuit then the Section -Section 240.4(D) specifies that 14 AWG copper conductors are to be protected by an overcurrent protective device with a rating or setting no higher than 15 amperes. Table 210.24, which summarizes the requirements for branch circuits with two or more outlets or receptacles, specifies that the minimum conductor size for a 20-ampere-rated branch circuit is 12 AWG. May not be applicable here??

what a place!!!!
No building codes and it sounds like they do whatever they want with electric too.

I guess I will have to get in contact with an electrician to confirm if this 14 gauge on 20A circuit is allowed here!

thanks

Walt


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