# thermostat



## wildleg (Apr 12, 2009)

depends. sometimes yes. mostly no.


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## Julius793 (Nov 29, 2011)

wildleg said:


> depends. sometimes yes. mostly no.


ok when yes when no? if its fed from a class 2 transformer what would the answer be?


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## Shockdoc (Mar 4, 2010)

Same KO ? I believe yes. Same conduit? conductors need to be rated 600volts.


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## wildleg (Apr 12, 2009)

Julius793 said:


> ok when yes when no? if its fed from a class 2 transformer what would the answer be?


maybe if you would provide more information it would be easier to answer you. hole in what ? control panel ? stud ? enclosure ? what voltage is the power ? is the thermostadt associated with the power wiring ? what type of wiring/cable is used for the thermostadt ? there are many variables.


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## Nebelectrician (Apr 17, 2012)

Julius793 said:


> can thermostat and line voltage go through the same hole/comduit?


Agree with wild leg, many variables. Personally I keep different class circuits separate


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## Julius793 (Nov 29, 2011)

wildleg said:


> maybe if you would provide more information it would be easier to answer you. hole in what ? control panel ? stud ? enclosure ? what voltage is the power ? is the thermostadt associated with the power wiring ? what type of wiring/cable is used for the thermostadt ? there are many variables.


1. holes in studs
2. 24v
3. not in any way
4. class 2


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## wildleg (Apr 12, 2009)

is it 300v thermostadt cable ? is the power wiring over 300v ? is it one hole or a whole line of holes where the power and class 2 cable have no separation ? what about the conduit you mentioned before ?


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## TLinSTL (Nov 28, 2011)

Within the last few months, 3 different jobs I've come on to towards the end have been called out by the inspector for running thermostat wire through the same hole in the studs as romex. By time I had gotten on the job and told the other guys, it was really too late to fix and they just figured the inspector wouldn't care. In 2 of the 3, it was the cause of the failure. Even holes up in soffits through the fire drywall require separate holes.


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## Amish Electrician (Jan 2, 2010)

I'd love to see the citation.

Even taking Article 725 (I think) at it's most imaginative scope, it only addresses running Class 2 wires within the same wiring method - and a thermostat cable next to a Romex cable is still outside the Romex.

The 'mixing circuits' debate has plenty of life left in it, but I just can't see any ban on using the same hole.


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## NacBooster29 (Oct 25, 2010)

God make sure there's no plumbing in the same bay too. The electrons love to jump out of romex everyone knows that.


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## acrwc10 (Jan 28, 2007)

TLinSTL said:


> Within the last few months, 3 different jobs I've come on to towards the end have been called out by the inspector for running thermostat wire through the same hole in the studs as romex. By time I had gotten on the job and told the other guys, it was really too late to fix and they just figured the inspector wouldn't care. In 2 of the 3, it was the cause of the failure. Even holes up in soffits through the fire drywall require separate holes.


:blink: WTF (where the fu--) did your inspector get that from? That makes no sense at all. The NM is insulated and jacketed, no leaking electrons to magically jump onto the unsuspecting (also insulated and jacketed) thermostat wire. Maybe you need to use the good NM cable that doesn't leak, then you will pass more inspections.


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## B4T (Feb 10, 2009)

I never heard of bell wire and NM cable in the same hole through a stud would lead to a violation.. that is crazy talk.. :blink::blink:


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## user4818 (Jan 15, 2009)

CABLES can share a knockout while CONDUCTORS cannot.


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## Magnettica (Jan 23, 2007)

Peter D said:


> CABLES can share a knockout while CONDUCTORS cannot.


Code section please. 


The section the OP should be looking at is article 725. I believe it was one of the questions on the NJ licensing exam too. I looked just now but couldn't find it. I have it highlighted in my 08' NEC but that's out in the truck and i'm watching the Devils in OT so I'm not leaving this chair.


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## user4818 (Jan 15, 2009)

Magnettica said:


> Code section please.


I hardly ever read the code book anymore so I have no idea, but it's in there. :thumbsup:


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## HARRY304E (Sep 15, 2010)

300.2 Limitations.
(A) Voltage. Wiring methods specified in Chapter 3 shall
be used for 600 volts, nominal, or less where not specifically
limited in some section of Chapter 3. They shall be
permitted for over 600 volts, nominal, where specifically
permitted elsewhere in this Code.



(C) Conductors of Different Systems.
(1) 600 Volts, Nominal, or Less. Conductors of ac and dc
circuits, rated 600 volts, nominal, or less, shall be permitted
to occupy the same equipment wiring enclosure, cable, or
raceway. All conductors shall have an insulation rating
equal to at least the maximum circuit voltage applied to any
conductor within the enclosure, cable, or raceway.
Informational Note No. 1: See 725.136(A) for Class 2 and
Class 3 circuit conductors.
Informational Note No. 2: See 690.4(B) for photovoltaic
source and output circuits.


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).


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## HARRY304E (Sep 15, 2010)

Peter D said:


> I hardly ever read the code book anymore so I have no idea, but it's in there. :thumbsup:


typical.


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## user4818 (Jan 15, 2009)

HARRY304E said:


> typical.



What's typical? I have most of the important code rules memorized, so it's not like I need to study it.


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## acrwc10 (Jan 28, 2007)

Peter D said:


> What's typical? I have most of the important code rules memorized, so it's not like I need to study it.


When I get an inspector that uses that method, I give them a run for their money. There is little room for "I know I read it somewhere" when your tell someone that they need to change something, thus delaying the job and costing money. One local inspector is almost afraid of me now because over the last 3 years everything he has called me on I challenged him on and proved him wrong. Nothing pisses me off more than uneducated inspectors, they are a public hazard by calling BS and missing real safety issues other trades work.


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## don_resqcapt19 (Jul 18, 2010)

> 725.136*(I) Other Applications. *For other applications, conductors of Class 2 and Class 3 circuits shall be separated by at least 50 mm (2 in.) from conductors of any electric light, power, Class 1 non–power-limited fire alarm or medium power network-powered broadband communications circuits unless one of the following conditions is met:
> (1) Either
> (a) all of the electric light, power, Class 1, non–power-limited fire alarm and medium-power networkpowered broadband communications circuit conductors or
> (b) all of the Class 2 and Class 3 circuit conductors are in a raceway or in metal-sheathed, metal-clad, non–metallic-sheathed, or Type UF cables.
> ...



(1)(a) clearly permits the thermostat wire to be run though the same holes as the NM cable.​


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## twistnwirebendnpipe (Jul 13, 2021)

acrwc10 said:


> When I get an inspector that uses that method, I give them a run for their money. There is little room for "I know I read it somewhere" when your tell someone that they need to change something, thus delaying the job and costing money. One local inspector is almost afraid of me now because over the last 3 years everything he has called me on I challenged him on and proved him wrong. Nothing pisses me off more than uneducated inspectors, they are a public hazard by calling BS and missing real safety issues other trades work.


That's big talk around here, and everywhere I've worked for 45 yrs. I've been around the block a couple a times. I've had some run ins with more than 1 inspector, engineer, architect, I've even had to ground PVC to satisfy water line grounding, [didn't say it made sense] [nor did I say all inspectors are wrapped up tight] in places failing inspections can prove costly. Article 1 says "The local authority having jurisdiction shall interpret the code." Better to throw the monkey on the back it belongs, than trying to school the unteachable.


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## MoscaFibra (Apr 15, 2021)

This all sounds residential, but I know in commercial we have been dinged with thermostats being FT4 instead of FT6 (plenum rated....sorry Canadian here so I use the Canadian code). We also use voltage classes to separate circuits...but thermostat and 120V resi circuits have never been in that issue.


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## Wardenclyffe (Jan 11, 2019)

Sound ten years old,...


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## Wirenuting (Sep 12, 2010)

Wardenclyffe said:


> Sound ten years old,...


9 years.


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## readydave8 (Sep 20, 2009)

Wirenuting said:


> 9 years.


wait for it . . .


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