low voltage cable (less than24v) and pneumatic tubing in

[huston]

Can pneumatic tubing be installed with low voltage wiring in the same raceway as it is an intergral part of a temperature control system. I am being told this violates 300.8 but I disagree on three points: 1. I believe this is referencing 600v cable, 2. this pneumatic tubing in the application above is not an "other" system its the same system and often times goes to the same device and a shared control panel 3. Panels are constructed and shipped all of the world that have DDC signal and pneumatic connections in the same enclosure which is also a raceway. I believe that 800.52 should apply to this type installation and I see the pneumatic tubing (which has very small pressured air) as no different than fiber optic or other nonconductive tubing. Please let me know your thoughts on this. Thank you,

 

[iwire]

Re: low voltage cable (less than24v) and pneumatic tubing in

Originally posted by huston:
Can pneumatic tubing be installed with low voltage wiring in the same raceway as it is an intergral part of a temperature control system. I am being told this violates 300.8 but I disagree on three points:


1. I believe this is referencing 600v cable,

Not only 600 v cable but any wiring covered from Chapters 1 to 7 of the NEC.

Originally posted by huston:
2. this pneumatic tubing in the application above is not an "other" system its the same system and often times goes to the same device and a shared control panel

As far as the NEC is concerned an air supply system is in fact another system from a electrical supply system regardless of them being part of the same machine.

Originally posted by huston:
3. Panels are constructed and shipped all of the world that have DDC signal and pneumatic connections in the same enclosure which is also a raceway.

The construction of those panels are not covered by the NEC.

Originally posted by huston:
I believe that 800.52 should apply to this type installation

It might, is it telephone or telegraph wiring?

If in fact the wires in question are covered by any Section in Chapter 8 of the NEC than 300.8 does not apply at all,

800.1 Scope.
This article covers telephone, telegraph (except radio), outside wiring for fire alarm and burglar alarm, and similar central station systems; and telephone systems not connected to a central station system but using similar types of equipment, methods of installation, and maintenance.

What is the function of the wires you wan to run with the air lines?

 

[huston]

Re: low voltage cable (less than24v) and pneumatic tubing in

Thank you for responding to this question:

I have some follow up information:

the pneumatic is mainly for static pressure discharge of the ductwork which has very little
pressurization.

the wiring is for temperature controls. Is this covered by Section 8? I assume so, as this is a low voltage application.

I know the construction of the panels is not covered by the NEC but the panel is a raceway and 300.8 covers raceways. I think a spade is a spade in this regard.

Jason

 

[iwire]

Re: low voltage cable (less than24v) and pneumatic tubing in

Originally posted by huston:
Thank you for responding to this question:

I have some follow up information:

No problem, keep in mind my responses are just my opinion of the requirements. You should get some more replies.

Originally posted by huston:
the pneumatic is mainly for static pressure discharge of the ductwork which has very little
pressurization.

No mention of pressure in 300.8 only that it can't be there.

Originally posted by huston:
the wiring is for temperature controls. Is this covered by Section 8?

Not normally.

725 is usually what would cover HVAC controls.

ARTICLE 725 Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits
I. General
725.1 Scope.
This article covers remote-control, signaling, and power-limited circuits that are not an integral part of a device or appliance.

Originally posted by huston:
I know the construction of the panels is not covered by the NEC but the panel is a raceway and 300.8 covers raceways.

What can I say?

Just because it would be easier to ignore the rules we can not.

The NEC requires me to run 6 AWG NM to a 50 amp range, the cord is 8 AWG and the factory wiring inside is 12 AWG.

I can't run 12 NM just because thats what the factory does.

[ January 05, 2006, 10:41 AM: Message edited by: iwire ]

 

[huston]

Re: low voltage cable (less than24v) and pneumatic tubing in

Thank you for your responses,

Here are a few more thoughts.

if 725 applies to the HVAC control cabling installations, than 725.56 (E) indicates what can be combined in the same raceway. Item #2 under E states " nonconductive and conductive optical fiber cables in compliance with article 770... how is this cable any different than nonconductive pneumatic tubing? Light and air are both nonconductive? Is this a correct assumption?

I understand the raceway comment, but its still frustrating.

 

[huston]

Re: low voltage cable (less than24v) and pneumatic tubing in

Also,

where does it indicate that 725 is for HVAC control cabling? Thank you,

Jason

 

[don_resqcapt19]

Re: low voltage cable (less than24v) and pneumatic tubing in

Guys,
If the low voltage conductors are covered by Article 725, then 300.8 does not apply. See 725.3.
Don

 

[iwire]

Re: low voltage cable (less than24v) and pneumatic tubing in

Originally posted by don_resqcapt19:
Guys,
If the low voltage conductors are covered by Article 725, then 300.8 does not apply. See 725.3.
Don

Jason that is why I said to get other opinions as well.

Looks like you may be all set.

 

[thinfool]

Re: low voltage cable (less than24v) and pneumatic tubing in

Others can deal with the code issues.

I do this kind of work for Johnson Controls and Siemens. What you describe was OK and practiced years ago, but no more.

Pipefitters have learned to run emt for their pneumatic lines. We have learned to tyrap our sensor and trunk cables neatly to legal points of support usually without conduit.

I would be dinged and have to redo any such installation either by the Elect. Inspector or by my employers.

Believe me, I have looked into it carefully as far back as 1978.

 

[petersonra]

Re: low voltage cable (less than24v) and pneumatic tubing in

IMO, you cannot so this.

I don't know where you came up with your idea that the rest of the world allows this. IEC electrical regulations require seperation as well.

 

[jbwhite]

Re: low voltage cable (less than24v) and pneumatic tubing in

is this a class 1, 2, or 3 system?

if class 1 then chapter 3 wireing methods apply. And you cannot put the tubing in the conduit.

if class 2 or 3 they do not. And you can put the tubing in the conduit.

 

[iwire]

Re: low voltage cable (less than24v) and pneumatic tubing in

Originally posted by jbwhite:
if class 1 then chapter 3 wireing methods apply. And you cannot put the tubing in the conduit.

That is what I was thinking also until Don pointed out 725.3 which leaves 300.8 out of Article 725.