AC unit list 40amps MAX

[Ron Bibler]

AC unit listed 40 amps MAX. Disconnect List 60 amps with a 55 amp fuse inside. with an unlisted breaker in the main panel as a 30 amp breaker.

I'm going to call for sparky to look at the complete systems. How would state this? and is it OK To have a unit listed with a 40amp Max on a 30 amp breaker? See the bottom breaker unmarked.

Best

Ron

[Roland Miller]

You can have this if the label says 40 amp max. A 30 will work but it has to be a HACR rated breaker and all are not. The fuses don't really count and the disconnect is the only thing it is accomplishing. Good idea to have a sparky look at it..

[Jeff Remas]

Agree with Roland but would like to know what size wire the branch circuit is fed by.

[Jim Luttrall]

AC unit listed 40 amps MAX. Disconnect List 60 amps with a 55 amp fuse inside. with an unlisted breaker in the main panel as a 30 amp breaker.

I'm going to call for sparky to look at the complete systems. How would state this? and is it OK To have a unit listed with a 40amp Max on a 30 amp breaker? See the bottom breaker unmarked.

Best

Ron

Two questions, what do you mean by "unlisted breaker" and what is the minimum breaker size on the AC name plate?

[Ron Bibler]

Two questions, what do you mean by "unlisted breaker" and what is the minimum breaker size on the AC name plate?

Unlisted breaker in the main panel.

22.9 minimum see the photo for the tag.

Best

Ron

[Jerry Peck]

Ron,

Do you have a photo of the label from the other side?

The label states: '?????amps or HACR type circuit breaker 40', to which I am guessing the '????' part is 'Max. fuse amps or HACR type circuit breaker 40'.

Which, if that is what it says, mean one could simply change out those 50 amp fuses 40 amp fuses.

Other than the fuse part of what Roland stated, I agree with Roland regarding breaker type and max allowed size.

Also, is that ???? amps 22.9 this: 'min. circuit amps 22.9'?

Not enough information on the visible part of the label to know much for sure. (added with edit, you posted another photo of the label while I was typing which answered my two questions above)

The circuit conductor size looks sufficiently large enough in the photo of the inside of the disconnect.

You mentioned an "unlisted breaker", you are referring to the center double pole breaker in the bottom quad breaker, right? If the weather was warm enough to run the a/c all you would have to do to verify that is to flip it off and see if the a/c still runs.

[Jim Luttrall]

A 30 amp (HACR) breaker is fine since it provides at least the minimum required.
If you me unlisted as in not UL listed... I don't get in to that unless it is another issue I am aware of like Zinsco. If you mean not listed as in the breaker is not labeled on the panel, it should be labeled and I would be careful not to guess that was the correct breaker unless I could track it to the unit.
Like others said, the other disconnects and breakers are red herrings. Look for the smallest maximum (the 30 amp breaker) and the smallest minimum (the wire and circuit size) to match the unit label.

[Ron Bibler]

Ron,

Do you have a photo of the label from the other side?

The label states: '?????amps or HACR type circuit breaker 40', to which I am guessing the '????' part is 'Max. fuse amps or HACR type circuit breaker 40'.

Which, if that is what it says, mean one could simply change out those 50 amp fuses 40 amp fuses.

Other than the fuse part of what Roland stated, I agree with Roland regarding breaker type and max allowed size.

Also, is that ???? amps 22.9 this: 'min. circuit amps 22.9'?

Not enough information on the visible part of the label to know much for sure. (added with edit, you posted another photo of the label while I was typing which answered my two questions above)

The circuit conductor size looks sufficiently large enough in the photo of the inside of the disconnect.

You mentioned an "unlisted breaker", you are referring to the center double pole breaker in the bottom quad breaker, right? If the weather was warm enough to run the a/c all you would have to do to verify that is to flip it off and see if the a/c still runs.

Thanks for all the help.

The center breaker is the one.

50 out side today to cool to run the unit.

See these lables hope this helps.

Best

Ron

[Jeff Remas]

The rating of the breaker seems to be the only issue if it is not HACR or listed.

[Ron Bibler]

I do not have a breaker in the main panel labeled for the HAVC.

To cold to test the unit today.

Best

Ron

[Richard Thacker]

Everything you need is on that label.

The min circuit listing of 22.9 amps will indicate that the wire size is to be no less than #10 CU wire (30 amp wire). The manufacturer is calling for a ccircuit/wire that is rated for at least 22.9 amps and that would be #10 copper. The max fuse is just that a maximum of 40 amps. If the disconnect is 50 amps, what is feeding it? IF the unlabeled 2 pole 30 breaker at the bottom of the service panel is feeding the AC disconnect that will be fine since the weakest link is the 30 amp breaker. You may have wanted to see where the circuit was tied in...many time a contractor will double tap the main service lugs. You could also have done a simple voltage test at the disconnect to see if the unlabeled breaker actually disconnected power to the unit.

Note: This is one of the few places where you can have a fuse that is allowed to be "over sized" for the circuit wire. Manufacturers will call for a lager fuse/breaker for the start up of motor loads, as it is stated on the label.

1. Is the supply circuit and whip #10 CU or larger. And it must be copper!
2. Is the source of the electric supply protected with a breaker 40 amps or smaller ( no less than 30 is recommended)

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[Jim Robinson]

I thought # 12 wire would be acceptable, since the ampacity is below 25 amps. Am I missing something on this AC wiring?

[Roland Miller]

#14 copper is code compliant..:)

[Richard Thacker]

#14 Cu is rated for a standard circuit of 15 amps.

#12 Cu wire is rated for a standard circuit of 20 amps.

The manufacturer is telling you not to use a circuit that can handle less than 22.9 amps. In this case #10 Cu wire or larger Cu wire must be used. Since 22.9 amps is greater than 20amps, #12 wire can not be used in this application.:)

[Roland Miller]

#14 copper is rated for 25 amps in 90 conductor. That's good enough..

[Richard Thacker]

When is #14 copper rated for an rla of 17.3 amps, a minimum circuit of 22.9 amps or protection of a 40 amp breaker?

Reminds me of a song...

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[Roland Miller]

When the use is listed in table 240.4(G)

[Jerry Peck]

#14 copper is rated for 25 amps in 90 conductor. That's good enough..

Also depends on the rating of the terminal in the equipment, if 60 / 75 / 90 degrees C. Applying the 90 degree C rating of the conductor is not allowed unless the equipment terminals are also rated 90 degrees C, and there are no derating factors to be considered, such as for ambient, here are some examples.

Take your 90 C rated wire in older equipment with terminals rated for 60 C, the rating of the 90 C rated wire is then no greater than the 60 C terminals, less derating for ambient. The 60 C rating for #14 for derating purposes is 20 amps, with an outdoor temperature of 96 degrees F (which many parts of the country experience) the derating factor (multiplier) is 0.82, thus that 20 amp rated 90 C conductor on 60 C terminals has a current rating of 16.4 amps, provided there is no further derating needed, such as for lack of maintaining spacing or bundling.

Take your 90 C rated wire in not so old equipment with terminals rated for 75 C, the rating of the 90 C rated wire is then no greater than the 75 C terminals, less derating for ambient. The 75 C rating for #14 for derating purposes is 20 amps, with an outdoor temperature of 96 degrees F (which many parts of the country experience) the derating factor (multiplier) is 0.88, thus that 20 amp rated 90 C conductor on 75 C terminals has a current rating of 17.6 amps, provided there is no further derating needed, such as for lack of maintaining spacing or bundling.

Take your 90 C rated wire in older equipment with terminals rated for 90 C, the rating of the 90 C rated wire is now the same as the 90 C terminals, less derating for ambient. The 90 C rating for #14 for derating purposes is 25 amps, with an outdoor temperature of 96 degrees F (which many parts of the country experience) the derating factor (multiplier) is 0.91, thus that 25 amp rated 90 C conductor on 90 C terminals has a current rating of 22.75 amps, provided there is no further derating needed, such as for lack of maintaining spacing or bundling.

Thus, your #14 AWG 90 degree C rated conductor IS NOT suitable for use in many areas of the country. In areas of the country where the temperature NEVER EXCEEDS 95 degrees F, you might be able to pull that off with your #14 AWG 90 degree C rated conductors ... might.

Provided there were no other derating factors to apply.

[Richard Thacker]

I just hate motors.:mad:

You will probably never go wrong by doing the simple way.:)

[Jerry Peck]

When the use is listed in table 240.4(G)

I've been waiting for Roland's response to my last post above, then I will explain why *even that* does not matter - not allowed to do it anyway.:)

[Richard Thacker]

JP, I can't wait...

"When you can't out smart them...Out dumb 'em":D

[Jerry Peck]

"When you can't out smart them...Out dumb 'em":D


Richard,

Don't get me wrong, I think Roland is a smart guy, but, like all of us, there are things we think we know which we later find out we really didn't know.

It has happened to me my share of the time too.

[Richard Thacker]

It was not a knock on Roland at all. It was more just a general quote. Sorry if it seemed out of line.

[Roland Miller]

with the information the OP gave and without making all the assumptions that Jerry made--#14 copper will work.

If and when other considerations are stated by the OP we can consider them in the mix and it may very well change the conductor size. All speculating about the "other" conditions does is confuse everyone.

The terminals of the remote condenser units I install and/or inspect have conductor leads that "wire nut" to the branch circuit. These can be the full 90 degrees as they are not rated.

[Jerry Peck]

with the information the OP gave and without making all the assumptions that Jerry made--#14 copper will work.

Before stating that, categorically that #14 WILL WORK, which you did in this ...

#14 copper is code compliant..:)
... one must either define what limitations they are placing on their be all and end all statement that ...

#14 copper is code compliant..:)
... otherwise they will be incorrect, as you are.

Now, let's go to this post ...

When the use is listed in table 240.4(G)
... specifically, which part of 240.4(G) allows for #14 AWG 90 degree C rated conductor insulation to be used as you stated?

[Roland Miller]

Jerry --you have been telling everyone how well you can read.

240.4(G) answer was a response to this question: "When is #14 copper rated for an rla of 17.3 amps, a minimum circuit of 22.9 amps or protection of a 40 amp breaker?" This is an overcurrent protection question..
I didn't say it was connected with the 90 degree column. Just straight up code, without any other know factors--#14 copper will work. And we don't know any other factors..

#10 will work but you might not get the job from the guy that knows the NEC..

[Jerry Peck]

Jerry --you have been telling everyone how well you can read.

240.4(G) answer was a response to this question: "When is #14 copper rated for an rla of 17.3 amps, a minimum circuit of 22.9 amps or protection of a 40 amp breaker?" This is an overcurrent protection question..

And that is the question I am asking about. *I* even quoted you so you would know what I was asking about.

So, back to my question:

Now, let's go to this post ...

When the use is listed in table 240.4(G)

... specifically, which part of 240.4(G) allows for #14 AWG 90 degree C rated conductor insulation to be used as you stated?


I didn't say it was connected with the 90 degree column.

Fair enough, I'll re-phrase that question "... specifically, which part of 240.4(G) allows for #14 AWG to be used as you stated?"

"Just straight up code."

[Roland Miller]

240.4(G) Overcurrent Protection for Specific Conductor Applications. Overcurrent protection for the specific conductors shall be permitted to be provided as referenced in Table 240.4(G)

The table then refers you to "Air-conditioning and refrigeration equipment circuit conductors, Article 440, Parts III, VI." Which is where the answer lies.

As you already know, this takes you to an area that is outside the normal protection requirements for conductors, such as it does for motors..

[Jerry Peck]

When the use is listed in table 240.4(G)


240.4(G) Overcurrent Protection for Specific Conductor Applications. Overcurrent protection for the specific conductors shall be permitted to be provided as referenced in Table 240.4(G)

The table then refers you to "Air-conditioning and refrigeration equipment circuit conductors, Article 440, Parts III, VI." Which is where the answer lies.

As you already know, this takes you to an area that is outside the normal protection requirements for conductors, such as it does for motors..

Yes, it does, and you are going in the direction I was expecting.

What, specifically, in Article 440, Parts III and VI allows for that 14 AWG to be used for "When is #14 copper rated for an rla of 17.3 amps, a minimum circuit of 22.9 amps or protection of a 40 amp breaker?", which was the question you were answering.