#6 NM wire in 1/2" hole?

[clare]

And if the manufacturer(on the UL label) specifies #6 wire be used for connection, it does NOT meet code if installed with #8 or #10

[trader_4]

It would seem if you're giving out the advice, you should know that no? And if not, googling "code definition continous load" should work.

What minimum duty cycle is

That doesn't matter, because per Gfre, all that has been taken into account by the engineers who designed and rated the eqpt. The eqpt rating plate is what governs, it says a circuit with minimum ampacity of 26A, which you then use to directly determine the wire size.

[trader_4]

Except of course that the manufacturer did not say #6 or any gauge on the UL label. Nor have I ever seen gauge on a similar label. The governing data on the eqpt label is the 26A, if he chooses to follow that. The manufacturer stated #6 gauge in the install manual, which was obviously written by a buffoon, because they don't understand the difference between conductors and grounds. The install instructions say that it's to be installed with

4 conductors and then they show only a 240V connection, no neutral, just like you'd expect with any other air conditioner. So, following that, even after correcting it to 3 conductors, plus ground, you'd have an extra wire that goes nowhere. Would you follow that too?

That 3.7 ton AC would have to be the most inefficient piece of crap ever made to need #6. It would be so inefficient, it couldn't meet the min SEER required today. It also states in the spec that the rated input power is 4600 watts. 4600 watts = 19 amps. There is nothing there that comes close to needing 6 gauge wire.

[trader_4]

You have your outside AC units swinging around in the breeze up there in Canada? Around here, they *are* installed with permanent wiring, not cords. And the cord reference is in the same lame drawing, that was obviously written by a buffoon. They confuse conductors with grounds and call for a 4 conductor cable. As I already said, even if you allow that they really mean 3 conductors, plus ground, it's still wrong. The drawing only shows two hots, ie a normal 240V AC connection. So, following that, we should get a big old honking 6 gauge 4 conductor stranded "cord". Then leave two conductors unused. Then let;s call the inspector over and see how he likes it.

Or we could use two #8 THWN stranded run inside liquidtight. Actually per the eqpt label, you could use #10, but since the 26A is close to the max for #10, I'd bump it up.

It is a good idea to use one size heavier cable than

Cable? Cord? Which is it now? Better rip out all your 14 gauge that's on 15 amp breakers, make it 12 gauge.

In general practice around here, people don't install permanent, outdoor AC eqpt with cords. And I've never seen a 3.7 ton AC unit on #6 anything, cord, stranded, solid, etc.

[trader_4]

You see outside permanently mounted AC condenser/compressor units on power cords much up there?

[clare]

So why does the instruction specify a #6?????? If the manufacturer's UL listing spec requires a #6, it doesn't meet code to connect with a #10.

[trader_4]

We don't have access to the UL listing spec. All we have are the eqpt rating plate and one page of the install manual. That one page, was obviously written by a complete buffoon. They call for #6 and in the diagram call it a cord. How many outside AC condenser/compressor units have you seen installed on cords?

And then they call for 4 conductor cord. Lets take that literally too. So, we have 4 conductors and a ground? WTF? OK, whooops, I guess they really meant 3 conductors plus ground. So we get a big honking #6 cord, with 3 conductors plus ground. Whooops! They only show two conductors actually used, ie like you'd expect for a 240V AC unit. So I guess the extra one is for good luck, but heh, they said to do it righ? In other words, whoever wrote that manual, proably in China, didn't know WTF they were talking about.

On the other hand, we do know the unit is rated at 3.7 tons. That the rated input power is 4600 watts and that the eqpt label says the min circuit ampacity is 26A. All that says #6 is nuts and that 10g would suffice. Since 26A is close, I'd go with #8. And I would not use a cord, which I don't think would even pass code here. I'd put THWN, #8, 2 conductors plus ground, inside liquidtight. The OP as always, can do as he chooses.

[Doug Miller]

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

conditioner

At maximum current.

[Doug Miller]

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

"Continuous load: a load where the maximum current is expected to continue for three hours or more." [NEC, Article 100]

See above.

Immaterial. The only relevant question is, does it pull maximum current for three hours or more?

It does not appear to meet the NEC's definition of a continuous load -- a definition you're clearly ignorant of.

From the data posted by the OP, apparently it's 26 amps.

Wrong yet again. I never said it would not approach 100% duty cycle, and that's not what's meant by "continuous load".

[Doug Miller]

trader_4 wrote in news:721afe4d-95af-4321-a785-f2428f838f82 @googlegroups.com:

conditioner

Not knowing what the Code says hasn't ever previously prevented him from giving electrical advice; no reason to expect that to change now, is there?

[Doug Miller]

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

[...]

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

UL labels specify voltage, amperage, wattage -- but when have you seen one that specifies the size of the circuit conductors?

[trader_4]

Agree with you except for the above. The "min circuit ampacity" is 26. The rated load amps is 19. It also says the rated input power is 4600W. Clearly it's running closer to 19 amps, not 26. The exact current is going to vary based on the exact conditions present at the time. But all that is taken into account when they spec'd the min circuit amps at 26. The unit is only 41K btu, ie 3.7 tons. It's impossible for a unit to need #6, if it drew that much power and only produced 3.7 tons, it would never meet the min govt SEER standards.

It's obvious whoever wrote that manual made several mistakes. If it were me, I'd use #8 and a 50A breaker, which is consistent with the unit label and be done with it. I suggested previously that if this needs to be permitted, the OP could take the relevant info to the inspector and ask. I for sure would do one of the above before I installed it with #6, using a

*4 conductor *cord*, because the lame manual says so.

[clare]

And how much current does this AC unit draw, steady state? And how long will it run on the hottest day of the year, in the hottest year in 10 years???

[clare]

If the AC unit runs at 26 FLA for 3 hours and 1 minute on the hottest day of the year, it is over 80% and "continuous" by code, so the wire needs to be derated to 80%., meaning it needs a larger cable.

[clare]

If the AC runs for 3 hours and 1 minute without shutting down at 26 amps, a #10 cable is undersized for the application. That is according to your interpretation of the code. Is it inconceiveable that this air conditioner could run for over 3 hours at a time???

If this AC can run for more than 3 hours without shutting down,and it draws 26 amps, it requires #8 cable. If the rating label states it requires a #6 cable, it requires a #6 cable to meet code. I don't pretend to know WHY the manufacturer specified a #6 cable, when according to code a #8 would be adequate. My only GUESS is it had something to do with the specification that the unit was to be connected with stranded cable (I believe that was part of the original post) - in which case the premises wiring could be #8 and the flex cable be #6.. The specification was 3 conductor # 6 flexible cable, and the OP misread that to be NMD or NMW6-3 + ground from the service panel to the unit.

That's MY take on it.

[gfretwell]

The U/L listing is on the label per the marking guide and relevant the number I saw was "minimum circuit ampacity 26 amps". I really would not pay much attention to anything else. This is the number provided by the engineer, not some tech writer who's first language is probably not English..

[clare]

I thought the OP said the label on the unit gave the circuit requirements and the cable specification. I could have misread that. My reader does not make it easy to go back to previous posts in a thread, so I'm going by memory.

[trader_4]

You're confused again. The 26 amps is not FLA, it's the spec for the minimum ampacity of the circuit. The rest is the wire size that will support 26A. You're taking what was already calculated by engineers and applying factors on top of the factors they already applied when they did the UL listing.

[gfretwell]

If it draws much over 15amps the seer would be so low you could not even install it in any state with an energy code.

[gfretwell]

Are you simply not paying attention here. The 80% does not apply here at all. It is already computed in the minimum circuit ampacity. Continuous load doesn't apply to motor loads anyway since the conductors are already sized to 125% of FLA.