[Adenmoor]

I'm working on an addition to my house.
At the same time, I plan on installing central heat and air.

I've already run 12 & 14 guage wiring for my lights and outlets.
What guage wiring should I run for the HVAC if it needs 220?
Also, circuit breaker capacity?

 

[Mike Finley]

50 amp circuit with 6/3 wire.

6/3 is 6 gauge with 4 wires in it.

Plus you will need a disconect box if this is going to a compressor outside.

 

[hatchet]

Above what Mike said - if you're pulling wire more than 140 feet or so I would suggest upsizing that wire to #4. Or change to copper wire. It's not likely that you will need to pull further than that - just something to think about. The a/c unit will tell you what you need for amperage. Mine needed 60amps. Not only a disconnect box but a disconnect box with a fusible link. The type of fusible link will be determined by the a/c unit recommendations(continual use or single use).

 

[Adenmoor]

Thanks!
My brother will be getting the unit for me, so I'll verify the specs then.
So far though, it looks like I'll be ok with 6-3.

 

[Mike Finley]

On a side note, I gave up 14 gauge wire long ago for my own residences or projects. 20 amp circuits with 12/2 is the only thing I put in now. The difference in cost is minimal, the labors the same, but the benefits are huge. I predict 15 amp circuits will follow the path of the fuse.

 

[Glasshousebltr]

Also, some places wont allow 14 anymore.

Bob

 

[Adenmoor]

You guys are right.
While looking around my house, all wiring is 12 guage and 20 amps.

Still waiting on the HVAC specs

 

[Unregistered]

Most residental units are single phase. Depending on the size of the equipment and what the length of the run is will determine the wire size. A disconnect is required per code. At least here in florida. The disconnect must be within reach of the condensor.If the condensor is single phase then you only need to run 6/2 stranded with ground. No need to spend the extra $$$$ on the 6/3 when you only need 2 legs and a ground.

 

[Unregistered]

Just a thought.

Forgive me if i'm wrong, but I always run the size wiring depending on how many amp sevice the "outdoor unit" will need. Of course you can run larger wiring, but not very cost conservative. If you're building an addition, the size of the addition will determine the size of the unit to use. If I was spending all that money on a project I'd want to save money where I could. Never seems like much in the beginning, but a dollar here and a dollar there does add up at the end. The odds of needing larger wiring for a unit like this in the future is not likely, cause the one you installed should be the one called for on your project. The odds of changing it in the future isn't very likely. Just do your research, decide if the ton usage is ideal for your space. Then decide if the unit you're installing is the right one for you.

 

[mark f]

a/c electrician

all ul. listed condensing units are marked with the "minimum circuit ampacity" and "maximum fuse or hvac breaker" on the product tag

 

[Unregistered]

Because of v-drop bigger the wire less the lights will dimm on start up.
it sure helps if the power co. has a high v- reading

 

[Speedy Petey]

As I read through this thread I was wondering when someone was going to ask the amperage. I also wondered where the first replier came up with 50 amps/6 wire with the only spec being given was 220 volts.

I am on the other side when it comes to 14 wire/15 amp circuits. Why do you guys hate them so? There is absolutely no way anyone can tell me that using #12 is safer, which I do get from time to time. Properly sized and logically loaded circuits are safe no matter what guage/breaker size.
You obviously don't do many multi gang boxes with dimmers or 4 ways very often. If I was told I had to do all my residential lighting wiring in #12 I would refuse the job. The thought of a 4 gang box with 3 dimmers and a 4-way in there (very common), in all #12 is frightening.
Is box fill an issue for you as well. I sometimes get close to full with 14 in switch boxes. With 12 it would be out of the question.
You all must love carrying around those 120 pound 1000' spools of 12/3.:cheesygri

 

[Unregistered]

As I read through this thread I was wondering when someone was going to ask the amperage. I also wondered where the first replier came up with 50 amps/6 wire with the only spec being given was 220 volts.

I am on the other side when it comes to 14 wire/15 amp circuits. Why do you guys hate them so? There is absolutely no way anyone can tell me that using #12 is safer, which I do get from time to time. Properly sized and logically loaded circuits are safe no matter what guage/breaker size.
You obviously don't do many multi gang boxes with dimmers or 4 ways very often. If I was told I had to do all my residential lighting wiring in #12 I would refuse the job. The thought of a 4 gang box with 3 dimmers and a 4-way in there (very common), in all #12 is frightening.
Is box fill an issue for you as well. I sometimes get close to full with 14 in switch boxes. With 12 it would be out of the question.
You all must love carrying around those 120 pound 1000' spools of 12/3.:cheesygri

Hmmmmm I didnt realize there were still ppl still using #14. Never really thought of it helping out with boxfill though. Actually I have never used #14. It is just easier for me to put everything on #12. Just stick up one reel of wire and use it till it empties. The 4 and 5 gangs are a pain though but I just try to dead end as much as possible on those.

 

[Adenmoor]

I've been told by my inspector that I need to terminate the wire in a j-box just before I poke out through the stucco (I haven't stucco'd yet, only lathed.)
Th inspector wants some sort of lathe ring for the water-proof conduit coming out.

What does this ring look like, where can I find one? Home Depot, Lowes, and Ganahl lumber have no clue what I'm talking about. It seems that only the inspector knows.

 

[Adenmoor]

Is it called a mud-ring? How do I make it water tight?

 

[raab420]

you should use a 60 amp dissconnect for your a/c unit.. NOT a 50 it has a bigger possibility of tripping more often when the heat is kicked on, and it will cause you hassel and you will end up wanting a 60 amp breaker you will have wasted the money on the 50 amp... do not use a 50 amp!

 

[BIGRED]

Huh? What are you guys talking about?

Speedy, every body is an electrician but you and I !

 

[Speedy Petey]

raab420,
1) What are you basing this on??? What specs do you see that I had missed??
How do you know a 50 is too little and a 60 is just right when you don't even know what this unit draws?

2) Why are you answering an almost TWO year old post like it was yesterday?


RED, I'm beginning to feel that way.

 

[BIGRED]

Everybody is an electrician but me

Why can't electricians answer electrical questions, plumbers plumbing questions and so on? If you do not know what you are talking then just read the posts and move on. You guys crack me up , I run across this all the time, guys in different trades always giving advice and telling you that they know all about your work, and believing they know what they are talking about!

 

[logical]

you should use a 60 amp dissconnect for your a/c unit.. NOT a 50 it has a bigger possibility of tripping more often when the heat is kicked on, and it will cause you hassel and you will end up wanting a 60 amp breaker you will have wasted the money on the 50 amp... do not use a 50 amp!

Why not a million amp...then it will never trip.