I have been ask by a local electrician where in the code does it say that low voltage wiring can or cannot be used in the wall spaces of a house. The local inspector has flagged him for this. His description was bell wiring. This would also apply to thermostat. and other low voltage controls.
Low Voltave wire in wall space
- Thread starter gce
- Start date
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volt101
Senior Member
- Location
- New Hampshire
Re: Low Voltave wire in wall space
Depending on the classification of the circuit
Class 1 - 725.27
Class 2/3 - 725.61
Depending on the classification of the circuit
Class 1 - 725.27
Class 2/3 - 725.61
pierre
Senior Member
- Location
- Westchester County, New York
Re: Low Voltave wire in wall space
411.4 Locations Not Permitted.
This is quite clear, as to not permitting a wiring method that is not part of Chapter 3.
Pierre
411.4 Locations Not Permitted.
This is quite clear, as to not permitting a wiring method that is not part of Chapter 3.
Pierre
curt swartz
Senior Member
- Location
- San Jose, CA
- Occupation
- Electrical Contractor
Re: Low Voltave wire in wall space
If this wiring was for low voltage lighting then Pierre is correct. If this was bell or thermostat wiring ask the inspector for a code reference.
If this wiring was for low voltage lighting then Pierre is correct. If this was bell or thermostat wiring ask the inspector for a code reference.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Low Voltave wire in wall space
Almost all Door bell and thermostat power supply's are class2 listed and 725.61(E) clearly allows CL2 and CL3 installed in dwellings. And 725.61(G) further allows many substitutions for Class 2 and Class 3 cables and is listed in Table 725.61.
400.8 does not allow any other flexible cables installed in, through, or behind building surface.
411.4 as Pierre has pointed out. But this section is for the installation low voltage lighting cable.
So door bell and thermostat wiring that is listed in table 725.61 is allowed to be "in the walls"
[ August 21, 2004, 12:18 AM: Message edited by: hurk27 ]
Almost all Door bell and thermostat power supply's are class2 listed and 725.61(E) clearly allows CL2 and CL3 installed in dwellings. And 725.61(G) further allows many substitutions for Class 2 and Class 3 cables and is listed in Table 725.61.
400.8 does not allow any other flexible cables installed in, through, or behind building surface.
411.4 as Pierre has pointed out. But this section is for the installation low voltage lighting cable.
So door bell and thermostat wiring that is listed in table 725.61 is allowed to be "in the walls"
[ August 21, 2004, 12:18 AM: Message edited by: hurk27 ]
hbiss
EC, New York NEC: 2017
- Location
- Little Falls, New York NEC: 2017
- Occupation
- EC
Re: Low Voltave wire in wall space
As a "building wiring engineer" you should be well aware that the answer is simply that you are using the wrong type of wire for your low voltage installations. Read article 400 (pay attention to 400.8) 725 and 800.
-Hal
As a "building wiring engineer" you should be well aware that the answer is simply that you are using the wrong type of wire for your low voltage installations. Read article 400 (pay attention to 400.8) 725 and 800.
-Hal
pierre
Senior Member
- Location
- Westchester County, New York
Re: Low Voltave wire in wall space
What exactly is a 'building wiring engineer'?
What exactly is a 'building wiring engineer'?
Re: Low Voltave wire in wall space
According to the wording in 725.1,"FPN: The circuits described herein are characterized by usage and electrical power limitations that differentiate them from electric light and power circuits; therefore, alternative requirements to those of Chapters 1 through 4 are given with regard to minimum wire sizes, derating factors, overcurrent protection, insulation requirements, and wiring methods and materials." This indicates that if the wiring meets the conditions presented in this Article then the wiring methods are changed accordingly per this Article. That being said,the control transformers to which we speak fall into the Class 2 or 3 classification. Next 725.3 does not address the running of the wire in this Class from wall spaces provided proper fire retardant methods are used per 300.21. From all I can tell, provided that the cable is Classed appropriately for the use, then it is permitted in wall spaces in houses.
PS thanks for the help from all. As a Design Electrical Engineer I do not aspire to know it all and therefore do like to bounce my interpretations of the Code off someone else who is familiar with the Code at times. For some of you it sounds like a little humility might be in order. Thanks even to those for your input as it made me think.
George H Carroll P.E.
[ August 22, 2004, 01:30 PM: Message edited by: gce ]
According to the wording in 725.1,"FPN: The circuits described herein are characterized by usage and electrical power limitations that differentiate them from electric light and power circuits; therefore, alternative requirements to those of Chapters 1 through 4 are given with regard to minimum wire sizes, derating factors, overcurrent protection, insulation requirements, and wiring methods and materials." This indicates that if the wiring meets the conditions presented in this Article then the wiring methods are changed accordingly per this Article. That being said,the control transformers to which we speak fall into the Class 2 or 3 classification. Next 725.3 does not address the running of the wire in this Class from wall spaces provided proper fire retardant methods are used per 300.21. From all I can tell, provided that the cable is Classed appropriately for the use, then it is permitted in wall spaces in houses.
PS thanks for the help from all. As a Design Electrical Engineer I do not aspire to know it all and therefore do like to bounce my interpretations of the Code off someone else who is familiar with the Code at times. For some of you it sounds like a little humility might be in order. Thanks even to those for your input as it made me think.
George H Carroll P.E.
[ August 22, 2004, 01:30 PM: Message edited by: gce ]
hbiss
EC, New York NEC: 2017
- Location
- Little Falls, New York NEC: 2017
- Occupation
- EC
Re: Low Voltave wire in wall space
For some of you it sounds like a little humility might be in order.
What's with the "building wiring engineer"? We do not answer questions from DIY'ers or those not involved in the trade as there could be liability issues. The occupation you listed is pretty suspicious as is your question and the fact that this is your first time here. We frequently have people posing as electricians using similar MO's and we really can't answer their questions.
-Hal
For some of you it sounds like a little humility might be in order.
What's with the "building wiring engineer"? We do not answer questions from DIY'ers or those not involved in the trade as there could be liability issues. The occupation you listed is pretty suspicious as is your question and the fact that this is your first time here. We frequently have people posing as electricians using similar MO's and we really can't answer their questions.
-Hal
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: Low Voltave wire in wall space
Slow down guys. If I recall during sign up, "Building Wiring Engineer" is one of the few choices that apply, sort of, to the kind of engineer that produces Contract Drawings for an EC to bid. Maybe the choices for occupation have changed since I signed up a while back, but give the guy a break, it was a valid question. I know loads of folks with PE next to their name, and loads of folks with EC next to their company name that wouldn't know the answer either.
George, your question was fine, and you absolutely may bounce code interpretations of heads in this forum, I often do .
Slow down guys. If I recall during sign up, "Building Wiring Engineer" is one of the few choices that apply, sort of, to the kind of engineer that produces Contract Drawings for an EC to bid. Maybe the choices for occupation have changed since I signed up a while back, but give the guy a break, it was a valid question. I know loads of folks with PE next to their name, and loads of folks with EC next to their company name that wouldn't know the answer either.
George, your question was fine, and you absolutely may bounce code interpretations of heads in this forum, I often do
.Re: Low Voltave wire in wall space
Thanks Ron, I do intend to. I did not understand the comments about building wiring engineer. I am a registered Consultant Engineer in Arkansas, Oklahoma and Mississippi. I am also a liscened Master Electrician in Arkansas. Thanks for your comments again.
George H Carroll, P.E.
Thanks Ron, I do intend to. I did not understand the comments about building wiring engineer. I am a registered Consultant Engineer in Arkansas, Oklahoma and Mississippi. I am also a liscened Master Electrician in Arkansas. Thanks for your comments again.
George H Carroll, P.E.
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