Condenser seal tight

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renosteinke

Senior Member
Location
NE Arkansas
You have well summed up exactly where we disagree.

Either you have a problem with the wires next to each other, or you do not. Whether whte THHN wires are loose, inside a pipe, with the thermostat wires, or wrapped in a jacket and called "Romex" won't matter - at least not in a technical sense.

Look to your specs for running CAT-5 data circuits. That confirms thi point. There's a situation where there's a problem with 'low voltage' being close to 'power.'

As for the thermostat and it's associated air conditioner, I think the code, and Webster's are pretty clear: There's no such prohibition, and the cited section does not apply.

Unless, of course, one wishes to maintain that the code is absolute, arbitrary, and it's words defined only by the convenience of the moment.
 

kwired

Electron manager
Location
NE Nebraska
You have well summed up exactly where we disagree.

Either you have a problem with the wires next to each other, or you do not. Whether whte THHN wires are loose, inside a pipe, with the thermostat wires, or wrapped in a jacket and called "Romex" won't matter - at least not in a technical sense.

Look to your specs for running CAT-5 data circuits. That confirms thi point. There's a situation where there's a problem with 'low voltage' being close to 'power.'

As for the thermostat and it's associated air conditioner, I think the code, and Webster's are pretty clear: There's no such prohibition, and the cited section does not apply.

Unless, of course, one wishes to maintain that the code is absolute, arbitrary, and it's words defined only by the convenience of the moment.
Wrapped in a jacket called "Romex" does matter. NM cable is a wiring method by itself. THHN/THWN is not and must be inside a raceway. You can place the class 2 control cable right next to a raceway, you can place the class 2 control cable right next to a NM cable. You can not place the class 2 control cable in the raceway with class 1 or power conductors.
 

renosteinke

Senior Member
Location
NE Arkansas
Right. We are in agreement that Romex is a wiring method, and that you can place a thermostat wire right next to it.

What you appear to either not understand, or choose to ignore, is my assertion that the code rules, as you present them, are illogical. It is my contention that either your understanding of the rules is wrong, or the code itself is wrong. Bad code makes for bad law.

You dishonestly throw in a reference to Class 2 control cables. Your reference is dishonest because the code section cited clearly says 'do not apply this section in this situation.' We are talking about the thermostat line for the air conditioner it controls, and code is quite clear: the cable and the power CAN be run together. That's the import of the use of the word 'integral' in the cited code section.

Unless, of course, we're not speaking English anymore.
 

iwire

Moderator
Staff member
Location
Massachusetts
Right. We are in agreement that Romex is a wiring method, and that you can place a thermostat wire right next to it.
Agreed

What you appear to either not understand, or choose to ignore, is my assertion that the code rules, as you present them, are illogical. It is my contention that either your understanding of the rules is wrong, or the code itself is wrong. Bad code makes for bad law.
There is nothing illogical about the codes under discussion.


You dishonestly throw in a reference to Class 2 control cables. Your reference is dishonest because the code section cited clearly says 'do not apply this section in this situation.'
Please tell me the code section that says 'do not apply this section in this situation'?


We are talking about the thermostat line for the air conditioner it controls, and code is quite clear: the cable and the power CAN be run together.
Please tell me the code section that says the thermostat cable and THHN power conductors can be run in the same conduit.


That's the import of the use of the word 'integral' in the cited code section.


There is absolutely no field wiring installed for an AC unit that is 'integral' to the AC unit.

The thermostat conductor we install between the unit and the thermostat are directly covered by Article 725

Unless, of course, we're not speaking English anymore.
How is that helpful?
 

renosteinke

Senior Member
Location
NE Arkansas
Well, I guess we're talking different forms of the English language.

My NEC says, under the scope of the cited section, that the section does not apply to control wires integral to the equipment.

Websters - which is used by my version of the English language - defines integral everything necessary to make the air conditioner work.

Therefore, the thermostat cable is an integral part of the air conditioner, thus the cited section does not apply. Seems pretty plain to me.

I notice a common practice, in many posts in this thread, to use general terms such as 'thermostat cable' or 'control wire,' as if all were the same. This is not the case. The cited section is perfectly plain that it applies only to control wires that are not required for the operation of that specific appliance.

Thus, the same wire, off the same bulk roll of material, would be in violation were it used for another purpose; say, as a doorbell wire sharing conduit with the air conditioner power circuit.

Less obvious is that not every 'low voltage' circuit is a 'power limited' circuit. Indeed, I suspect that most thermostat circuits are not 'power limited.' That term has a specific meaning to UL, with specific testing protocols, where the desire is to absolutely guarantee that the circuit never get more than a certain amount of power. An example of such an application would be for an 'intrinsically safe' application. Even the use of a "Class 2" transformer is not, in itself, enough to make it a 'power limited' circuit; the transformer is but a part.

IMO, Article 725 is grossly mis-applied, and this remains the case despite the code making it quite plain with the qualification in their scope of the article. That this article is numbered in the 700's ... as one of the exceptional, very limited circumstances .... and not in the 300's as a general rule for wiring methods ought to be another clue. One might as well try to apply 760 (Fire Alram Systems) to thermostat circuits- so what if it's outside the scope of the article!

To sum it up ...
1) The code does not prohibit the practice; and,
2) There is not technical reason to require the separation.

Thus, the question is: How can it be logical to assert there's anything wrong with the practice?
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Integral can also be read as "internal parts of the equipment" and that is its intended meaning in Article 725. If we would use your definition, then there would be no application for Article 725.
There is no question that Article 725 applies to the control circuit for a HVAC system. As far as the transformer not making a circuit a Class 2 circuit, that is exactly what does make it a Class 2 circuit. Look at 725.121(A). A listed Class 2 transformer or power supply is all you need to be able to say that the circuit is a Class 2 circuit.
 

iwire

Moderator
Staff member
Location
Massachusetts
To sum it up ...
1) The code does not prohibit the practice; and,
2) There is not technical reason to require the separation.
To sum it up.

1) You are wrong. 725.136 prohibits it.

2) The reason is a fault in a conduit containing both power and class 2 condutors can cause a higher voltage and current onto the class 2 wiring.


725.136 Separation from Electric Light, Power, Class 1,
Non?Power-Limited Fire Alarm Circuit Conductors,
and Medium-Power Network-Powered Broadband
Communications Cables.

(A) General. Cables and conductors of Class 2 and Class 3
circuits shall not be placed in any cable, cable tray, compartment,
enclosure, manhole, outlet box, device box, raceway,
or similar fitting with conductors of electric light,
power,
Class 1, non?power-limited fire alarm circuits, and
medium-power network-powered broadband communications
circuits unless permitted by 725.136(B) through (I).
 

iwire

Moderator
Staff member
Location
Massachusetts
My NEC says, under the scope of the cited section, that the section does not apply to control wires integral to the equipment.
Can you tell me what section you are looking at?

Websters - which is used by my version of the English language - defines integral everything necessary to make the air conditioner work.

Therefore, the thermostat cable is an integral part of the air conditioner, thus the cited section does not apply. Seems pretty plain to me.
So simple it is incorrect.


By your choice of defintion the branch circuit is also integral to the unit.

As would be the panel, the service and all the wiring back to the power company genertor. The unit cannot run without the branch circuit even more than it cannot run with out a thermatst.

I notice a common practice, in many posts in this thread, to use general terms such as 'thermostat cable' or 'control wire,' as if all were the same. This is not the case. The cited section is perfectly plain that it applies only to control wires that are not required for the operation of that specific appliance.
Again, the thermostat wiring is in fact covered by 725.

Less obvious is that not every 'low voltage' circuit is a 'power limited' circuit. Indeed, I suspect that most thermostat circuits are not 'power limited.' That term has a specific meaning to UL, with specific testing protocols, where the desire is to absolutely guarantee that the circuit never get more than a certain amount of power. An example of such an application would be for an 'intrinsically safe' application. Even the use of a "Class 2" transformer is not, in itself, enough to make it a 'power limited' circuit; the transformer is but a part.
Actully as long as the transfomer is marked class 2 all the wiring on the load side of it is class 2.

IMO, Article 725 is grossly mis-applied,
And IMO you have grossly misinterpreted it.
 
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texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
IMHO there is absolutely no doubt that class 2 circuits cannot be run in the same raceway as power conductors. I think the code is crystal clear on this and I have never seen an AHJ, instructor, peer, etc say otherwise. Some say you can "reclassify" the circuit as a class 1, which I also think is bogus. If the entire circuit including the supply and all the components are designed and built to class 2 standards, there is no such thing as reclassifying it.
Back in the '70's in some areas it was common practice however to mix power and class 2 wiring, but I don't think even back then it was code compliant. Also in some areas it was thought if you used rated conductors it was OK, but I don't think this was ever compliant either.
 

kwired

Electron manager
Location
NE Nebraska
Some say you can "reclassify" the circuit as a class 1, which I also think is bogus. If the entire circuit including the supply and all the components are designed and built to class 2 standards, there is no such thing as reclassifying it.
I mentioned this early in this thread. To reclassify it, you have to get rid of CL2 cables and use use a Ch 3 wiring method, you would need to replace the thermostat or any other device with devices that do not have class 2 ratings. If you wanted to pull control conductors in raceway with power conductors they would need insulation rating equal or greater than voltage of power circuit.
 

renosteinke

Senior Member
Location
NE Arkansas
I see two fair questions, ones a;ready answered, but I shall repeat the answers.

What section am I looking at? The "scope," or 725.1. "This article covers ..... circuits that are not an integral part of a device or appliance."

So, what is an 'integral' part? For that I am using the dictionary meaning. I gave Websters' definition before; just for giggles, let's see what Dictionary.com has to say:
1. of, pertaining to, or belonging as a part of the whole; constituent or component: integral parts.
2. necessary to the completeness of the whole: This point is integral to his plan.
3. consisting or composed of parts that together constitute a whole.
4. entire; complete; whole.

That's not "my" definition; that's the meaning of the word. Since the air conditioner simply cannot function without the thermostat line, I believe that "necessary to the completeness of the whole" applies best.

Perhaps "Integral can also be read as "internal parts of the equipment"" in some other language, but I do not find any dictionary meaning that would allow for that. Perhaps that's what the code panel meant to say - or, perhaps not. Perhaps their concern was limited to circuits completely unrelated to the appliance .... or, perhaps, they wished to make it clear that it was perfectly fine to run the thermostat cable through that bit of sealtite. They didn't have to use that word 'integral.'

Or, perhaps, we have yet another instance of the code being written by engineers who think they are lawyers- yet also have marginal literacy. In that case, I'm reminded of the late Mayor Daley, who chastised the press for not reporting what he 'meant' to say.

Some on the Holt forum have boasted as to their 'success rate' regarding NEC proposals. All is good for them - yet, I also have a very nice stack of rejected proposals, where I have raised matters such as this one, and the panel's reply was "no need, we already said that in the code." Were I to propose that 725.1 add an FPN to the effect that "It's OK to run the thermostat line in the sealtite," I would fully expect the panel to reply that the scope already makes it plain that you can do it.

IMO, when one applies the code to something that the code specifically says not to apply it, they're the ones mis-applying the code.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
..." Were I to propose that 725.1 add an FPN to the effect that "It's OK to run the thermostat line in the sealtite," I would fully expect the panel to reply that the scope already makes it plain that you can do it.
...
And I would expect that the proposal would be rejected, but not because the scope currently permits that, but for the exact opposite.

Can you cite anything from any published document that reads this scope the way you read it?

If we read the scope as you want us to, can you give an example of where Article 725 would apply? If the circuits or wiring is needed to make the equipment work, the would be "intergral to the equipment" and not be covered by Article 725. If they are not needed to make the equipment work why were they installed?
 
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renosteinke

Senior Member
Location
NE Arkansas
I cannot cite anything that allows for my reading, but for the basics of grammer - and the dictionary meaning of the words.

As for an example of where 725 would apply, I have given examples. For example, laying the Cat-5 data cables in the same trough as the power cables. The key to this section appears to be whether the cables in question are related to the equipment being powered, or not.

I went into possible 'technical' reasons in an attempt to understand the 'why' of the rule .... once you understand the 'why,' implementation is so much easier!

Remember ... a building has many circuits. Even a house has more 'low voltage' circuits than the one to the thermostat. Alarm, doorbell, phone, etc. Many of these do not have any 'power' circuit associated with their equipment at all.
 
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texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
I cannot cite anything that allows for my reading, but for the basics of grammer - and the dictionary meaning of the words.

As for an example of where 725 would apply, I have given examples. For example, laying the Cat-5 data cables in the same trough as the power cables. The key to this section appears to be whether the cables in question are related to the equipment being powered, or not.

I went into possible 'technical' reasons in an attempt to understand the 'why' of the rule .... once you understand the 'why,' implementation is so much easier!

Remember ... a building has many circuits. Even a house has more 'low voltage' circuits than the one to the thermostat. Alarm, doorbell, phone, etc. Many of these do not have any 'power' circuit associated with their equipment at all.
Let preface my comments by saying I admire your tenacity and I like a good healthy debate without being insulting. I made clear in my earlier post the camp I'm in on this issue.
Do any of the AHJ's you work in allow class 2 wiring with the power conductors? Also, have you studied the Handbook for their take on this? IMHO opinion it's pretty clear.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
I cannot cite anything that allows for my reading, but for the basics of grammer - and the dictionary meaning of the words. ...
I am not aware of anyone else who reads it that way. I just don't see that you would be the only one to have this correct and all of the rest of us have it wrong.
 

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
Just for grins, I looked back in the 1975 NEC for class 2 circuits. The requirements then were similar to today and crystal clear that this is not allowed.
 

kwired

Electron manager
Location
NE Nebraska
I cannot cite anything that allows for my reading, but for the basics of grammer - and the dictionary meaning of the words.
I have to agree with your definitioin as far as dictionary is concerned. I also feel that is not what was intended to be the meaning of said sections. Maybe code making panels need to consider this possible interpretation.

Have you had inspectors buy into this interpretation and allow such installations?

Just something to throw out there - a furnace would not have to have a thermostat connected to the control terminals to function. Jumper proper terminals together and put a control on the supply circuit and you have eliminated the need for the low voltage thermostat. The typical low voltage thermostat probably has performance enhancements that a control on the supply voltage would not be able to give.
 

renosteinke

Senior Member
Location
NE Arkansas
A few fair points, and I think matters would be helped if I put some 'personal perspective' on things.

First off, I don't insist things go my way all the time ... I only insist on having my 'vote,' as it were.

It was about a decade ago that Joe Tedesco made the thermostat wire his 'favorite violation,' and published plenty of pictures of what he asserted were violations. I had two problems with Joe's position: first, I wasn't sure it was a violation; and, second, his pictures didn't make the case. I learned when I looked into several A/C installs that the thermostat wire is typicall not run by the electrician, but by the HVAC guy, and is almost always run with the line set. So- just because you don't see the wire does not mean it's in the sealtite.

On my own A/C installs, the issue of running the thermostat wires with the power wires has never come up; that is, I never saw a reason to do so. The thermostat wire typically has a different point of entry to the unit than the power wires, and running the thermostat wire with the power would make things harder for me. I might even have to cut a hole in a partition within the unit to pass the thermostat wire from the wiring compartment.

From a technical view, as I mentioned once, not every low voltage circuit is a 'power limited' circuit- and there's more to such a circuit than simply a "class 2" transformer powering it. I don't think any of us are in a position, in the field, to be able to tell just by looking at things whether they're limited circuits or not. We have to take the next step, and ask 'why?' As in, 'what happens if a transient is induced on this line?'

With that in mind, I am biased towards an extremely limited application of 725. I believe that, if this was meant as a general rule, its' proper place would be in Article 300, with all the other basic wiring practices.
 

don_resqcapt19

Moderator
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Location
Illinois
Occupation
retired electrician
... and there's more to such a circuit than simply a "class 2" transformer powering it. ...
If the power supply (transformer or other source) is listed as a Class 2 power supply, the circuit connected to it is a Class 2 circuit and you don't need anything else to determine that.
 
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