#6 NM wire in 1/2" hole?

[clare]

I just went bact to the OP's post. I quote: "Hi, I'm the OP. Yes, the mini split a/c system specs explicitly call for a 50amp breaker and #6 AWG (although I shudder to think that it'll actually use that much, with a 16 SEER)."

What does the code say about over-protecting a cable? The cable is protected by a 50 amp breaker. Going by "general code" you cannot run an AWG10 circuit on a 50 amp circuit. What specifics outside of the "general code" would allow the cable to be protected with an over-rated protection device? And yes, the air conditioner in my house is connected with stranded flexible conductors from the house to the outside unit - run through weatherproof flexible conduit to the "protected disconnect" - a weatherproof single circuit circuit breaker enclosure. The outdoor unit sits on a plarform of concrete blocks on a base of concrete patio stones, and is not bolted down.. Been that way for over

40 years. (except the original unit sat right on the patio stones, I raised the unit on concrete blocks to keep it out of the dirt and leaves when I had the unit replaced.

[trader_4]

OMG, here we go again. Gfre went through that days ago. I did too when yesterday someone started in with the same nonsense. The 15 amps for 14g, 20 amps for 12g, 30 amps for 10g rules works for lights and receptacles. It doesn't work for motor and compressor loads. You can indeed have a 50 amp breaker on 10g wire because the overcurrent protection in the AC load is in the AC. The breaker is there to protect against short circuits and it needs to be 50A to handle the brief startup current.

The rest of the code that covers motors, HVAC compressors, etc.?

And you call that a *cord* up in Canada? Around here we call that THWN run in liquidtight.

You see any up there that use #6?, especially a minisplit that's just

3.7 toms? If it needed that much power it would be such a pig that it could not be sold because it wouldn't meet the min SEER standards. That's the nutty part about this. Just from practical experience it's obvious that #6 is a mistake.

And back to the original issue, here's another way of looking at it. You're looking in the wrong end of the telescope. You're trying to analyze the load, apply rules and then size the circuit. The engineers already did that. They put "min circuit ampacity 26A on the UL label. That means the load is saying, "Hook me up to a circuit capable of supplying 26A or more."

[trader_4]

+1

I made exactly the same point. The spec sheet says the rated imput wattage is

4600W. That's 19A, which also happens to be the compressor RLA. It's 41000btu, 3.7 tons. And it's 16 SEER. You couldn't sell it here period, it wouldn't meet the min federal SEER standards. Just from practical experience, #6 makes no sense.

Clare is looking in the wrong end of the telescope. He's trying to analyze the load. The engineers already did that and put the "min circuit ampacity 26A" on the UL label. The load is saying, "Hook me up to a 26A or greater circuit."

[clare]

How many BTUs is the unit? If it is a high BTU unit, the seer could still be pretty good with over 25 amps of current draw.

Regardless - the OP clearly stated the installation instructions specified #6 cable and a 50 amp breaker. He also stated it requires a "minimum ampacity" of 26 amps.

That is all we KNOW.

Do we have the manufacturer and model number of this "mythical beast"???

[clare]

And none of us knows enough about this "mythical beast" to know why it is specified to be connected to a 50 amp breaker by AWG6 cable.

It's all conjecture at this point - your conjecture and mine equally valid until more real information is provided.

[Doug Miller]

[e-mail] wrote in news: [e-mail]:

4ax.com:

Still wrong. Go back and read the definition I quoted. I was going to say, "read it *again*" but it doesn't appear that you've read it once.

"Interpretation"?? The language is pretty plain -- but you have to actually, you know, *read* it first, before you know what it says.

It says, "... expected to continue for three hours or more".

[Doug Miller]

[e-mail] wrote in news: [e-mail]:

Irrespective of what the OP may or may not have written, it's pretty clear that you're not actually very familiar with what is, or is not, on a UL label.

Just stop. You're only digging the hole deeper.

[clare]

And on a very hot day I could expect my air conditioner to run for more than 3 hours at a time.

[gfretwell]

He actually posted the model number and I had no problem finding the documentation. That is where I got the minimum ampacity. It is a tad less that 4 tons if he has the maximum number of evaporators connected. If there are fewer, it uses less power.

[gfretwell]

I have pointed out several times "continuous load" issue does not even apply to motor circuits. The 80% is an article 430/440 requirement and was engineered into the minimum circuit ampacity specification.

Let me do a calc for you

Take a 120v 1HP motor that has a 16a FLA The conductor needs to be sized at 125% of FLA (the inverse of 80%) That is 20 amps. (430.22) Table 310.16 says that can be a 14 gauge copper wire, even in the 60c column. You are also allowed to increase the over current device to 250% of FLA or 40 amps as long as the motor has overload protection (internal or external) (430.52)

So you have a 1HP motor, on 14 gauge wire with a 40 amp breaker.

The same type of logic works in air conditioners. Since these are complex machines with several motors and other loads, U/L requires that there is a label with the computed values of "maximum over current device" and "minimum circuit ampacity" from the manufacturer. Both of those numbers are in the installation guide I found and they specify 50a breaker and minimum ampacity of 26a. That is 10 gauge wire.

Nothing else in that pamphlet means shit when you are sizing the breaker and the wire.

[trader_4]

Maybe it's time to get a new reader? I don't know how anyone can competently follow a thread without being able to go back to previous posts.

[trader_4]

I think I'm starting to detect a big part of the problem here. You've now said that with your newsreader you can't go back and view previous posts. Now you're asking how many BTUS is the unit? I've posted that about 6 times recently. You also haven't replied to any of my posts. So, it's obvious you've set your newsreader to ignore my replies or else you're deliberately avoiding them and God knows what else. You're flying in the dark.

Again, that was stated in previous posts. It's not all we know, because at least Gfre and I have pulled up the actual spec sheet. For example, you've asked "How much current does this draw?". The spec sheet clearly says the RLA for the compressor is 19, the fan 1, the rated power input is 4600 Watts. Again, I've posted that many times now, but you apparently don't give a damn so you just ignore me and make an ass of yourself.

Sea Breeze SMZ42H46ZOGX.

[trader_4]

Plus it doesn't matter, because all of that was taken into account by the engineers when they put "min circuit amapacity 26" on the UL label. He's trying to analyze the load all over again, when it's been done and the load is saying "hook me up to a 26A or better circuit".

[trader_4]

+1

This is unbelievable. He hasn't looked at either the spec sheet or the pertinent data from it, which has all been posted here. In particular, he's asking how many BTUs it is? I've posted about 6 times that it's

41000, or 3.7 tons. And that the RLA of the compressor is 19A, the fan is 1A, yet he's pretending it's normal running amps could be 26A for 3 hours? Good grief!

And just from practical experience, has anyone ever seen a new 3.7 ton AC connected with #6? As you pointed out, if it took that much power it couldn't be sold because it wouldn't meet the min SEER standards. That install manual has other big mistakes in the wiring section, it calls for "4 conductor cord", when what they clearly show connected is only the normal 2 conductors plus ground. Clare apparently has even bought that and was arguing for connecting it with a "cord".

I think he's ignoring me. I guess it's better to remain in the dark.

[gfretwell]

I am even disturbed a little about the use of "cable". I suppose you could use UF or SE if it was properly protected but the usual installation from the disconnect to the condenser will be in sealtite with THHN/THWN.