Originally Posted By: jpeck
This post was automatically imported from our archived forum.
Under what conditions is wiring allowed to be in or through ducts or plenums used for HVAC?
–
Jerry Peck
South Florida
Under what conditions is wiring allowed to be in or through ducts or plenums used for HVAC?
Originally Posted By: jtedesco
This post was automatically imported from our archived forum.
| Quote: |
| Plenum. A compartment or chamber to which one or more air ducts are connected and that forms part of the air distribution system.
300.22(B) Ducts or Plenums Used for Environmental Air. Only wiring methods consisting of Type MI cable, Type MC cable employing a smooth or corrugated impervious metal sheath without an overall nonmetallic covering, electrical metallic tubing, flexible metallic tubing, intermediate metal conduit, or rigid metal conduit without an overall nonmetallic covering shall be installed in ducts or plenums specifically fabricated to transport environmental air. Flexible metal conduit and liquidtight flexible metal conduit shall be permitted, in lengths not to exceed 1.2 m (4 ft), to connect physically adjustable equipment and devices permitted to be in these ducts and plenum chambers. The connectors used with flexible metal conduit shall effectively close any openings in the connection. Equipment and devices shall be permitted within such ducts or plenum chambers only if necessary for their direct action upon, or sensing of, the contained air. Where equipment or devices are installed and illumination is necessary to facilitate maintenance and repair, enclosed gasketed-type luminaires (fixtures) shall be permitted. |
--
Joe Tedesco, NEC Consultant
www.nachi.org/tedescobook.htm
Originally Posted By: jpeck
This post was automatically imported from our archived forum.
Joe,
I have the code section still up on my other monitor. I KNOW what it says, I want to know what others think it says.
What say you?
--
Jerry Peck
South Florida
Originally Posted By: jtedesco
This post was automatically imported from our archived forum.
Jerry:
What part of this rule you are having trouble understanding? How would others see or read this rule in any other way? The rule is clear and does not allow methods that are not included in the text.
--
Joe Tedesco, NEC Consultant
www.nachi.org/tedescobook.htm
Originally Posted By: jpeck
This post was automatically imported from our archived forum.
| jtedesco wrote: |
| Jerry:
What part of this rule you are having trouble understanding? How would others see or read this rule in any other way? The rule is clear and does not allow methods that are not included in the text.  |
It doesn't even allow those. 
With but one exception, and I have yet to see it (but maybe you have).
What exception am I referring to?
--
Jerry Peck
South Florida
Originally Posted By: jtedesco
This post was automatically imported from our archived forum.
Jerry:
2005 change will prohibit the following. What exception are you talknig about?
Courtesy: www.iaei.org
--
Joe Tedesco, NEC Consultant
www.nachi.org/tedescobook.htm
Originally Posted By: jpeck
This post was automatically imported from our archived forum.
| jtedesco wrote: |
| What exception are you talknig about? |
300.22 Wiring in Ducts, Plenums, and Other Air-Handling Spaces.
(B) Ducts or Plenums Used for Environmental Air. ...
Equipment and devices shall be permitted within such ducts or plenum chambers only if necessary for their direct action upon, or sensing of, the contained air."
--
Jerry Peck
South Florida
Originally Posted By: jtedesco
This post was automatically imported from our archived forum.
| Quote: |
| Flexible metal conduit and liquidtight flexible metal conduit shall be permitted, in lengths not to exceed 1.2 m (4 ft), to connect physically adjustable equipment and devices permitted to be in these ducts and plenum chambers. |
I think that the sentence you mentioned has to do with the use of these two wiring methods only -- "Greenfield" and "Sealtight" in the 2002 NEC.
The text should be arranged to put the sentence you describe first, or in a separate subparagraph. Send in a proposal.
--
Joe Tedesco, NEC Consultant
www.nachi.org/tedescobook.htm
Originally Posted By: jpeck
This post was automatically imported from our archived forum.
Joe,
This is the way it reads (as currently in the 2002).
(B) Ducts or Plenums Used for Environmental Air. Only wiring methods consisting of Type MI cable, Type MC cable employing a smooth or corrugated impervious metal sheath without an overall nonmetallic covering, electrical metallic tubing, flexible metallic tubing, intermediate metal conduit, or rigid metal conduit without an overall nonmetallic covering shall be installed in ducts or plenums specifically fabricated to transport environmental air. Flexible metal conduit and liquidtight flexible metal conduit shall be permitted, in lengths not to exceed 1.2 m (4 ft), to connect physically adjustable equipment and devices permitted to be in these ducts and plenum chambers. The connectors used with flexible metal conduit shall effectively close any openings in the connection. Equipment and devices shall be permitted within such ducts or plenum chambers only if necessary for their direct action upon, or sensing of, the contained air. Where equipment or devices are installed and illumination is necessary to facilitate maintenance and repair, enclosed gasketed-type luminaires (fixtures) shall be permitted.
Now, I CAN break it up to be more readable, something like this (as I read it):
(B) Ducts or Plenums Used for Environmental Air.
Only wiring methods consisting of Type MI cable, Type MC cable employing a smooth or corrugated impervious metal sheath without an overall nonmetallic covering, electrical metallic tubing, flexible metallic tubing, intermediate metal conduit, or rigid metal conduit without an overall nonmetallic covering shall be installed in ducts or plenums specifically fabricated to transport environmental air.
Flexible metal conduit and liquidtight flexible metal conduit shall be permitted, in lengths not to exceed 1.2 m (4 ft), to connect physically adjustable equipment and devices permitted to be in these ducts and plenum chambers. The connectors used with flexible metal conduit shall effectively close any openings in the connection.
Equipment and devices shall be permitted within such ducts or plenum chambers only if necessary for their direct action upon, or sensing of, the contained air.
Where equipment or devices are installed and illumination is necessary to facilitate maintenance and repair, enclosed gasketed-type luminaires (fixtures) shall be permitted.
--
Jerry Peck
South Florida
Originally Posted By: Greg Fretwell
This post was automatically imported from our archived forum.
Where are you going with this Jerry? Are you asking if a homeowner can fish an MC cable from the 2d floor to the panel in the basement via the ductwork?
Originally Posted By: jpeck
This post was automatically imported from our archived forum.
| Greg Fretwell wrote: |
| Are you asking if a homeowner can fish an MC cable from the 2d floor to the panel in the basement via the ductwork? |
Is that space being used as a "duct" or a "plenum"?
That should answer your question.
--
Jerry Peck
South Florida
Originally Posted By: Greg Fretwell
This post was automatically imported from our archived forum.
Jerry do you think MC cable is a device or equipment?
I see the cheese out there but I am not sure where the trap is that you want us to stick our head in.
Originally Posted By: jpeck
This post was automatically imported from our archived forum.
| Greg Fretwell wrote: |
| Jerry do you think MC cable is a device or equipment? |
From the 2002 NEC.
Equipment. A general term including material, fittings, devices, appliances, luminaires (fixtures), apparatus, and the like used as a part of, or in connection with, an electrical installation.
Your answer it right there. Yes. it IS equipment, by definition.
| Quote: |
| I see the cheese out there but I am not sure where the trap is that you want us to stick our head in. |
This is not a trap. This is simply something I found out and am sharing.
For a better explanation than I can give, you will need to get Mike Holt's new video when it comes out. It is nearing completion at this time.
Like this: Receptacles used for the assembly and disassembly of rides (like fairs and carnivals, etc.) must have GFCI protection. However (  my catch  ) IF the receptacle is only used for assembly, and A DIFFERENT receptacle is used for disassembly, GFCI protection is NOT required. The current wording allows the operator to use the top half of a duplex receptacle for assembly and the bottom half of it for disassembly, and that will not require GFCI protection.
I will be submitting a code change for the 2008 code to make it read "Receptacles used for the assembly OR disassembly". Just that one little word makes all that difference. There is a fun exchange on the video regarding this.
--
Jerry Peck
South Florida
Originally Posted By: roconnor
This post was automatically imported from our archived forum.
I dont agree that wiring is “equipment”, and should therefore not be allowed at all unless under 300.22 in limited lengths. The problem with wiring in ductwork is that it could wick fire to other areas or create toxic fumes in supply air.
Most cables in ductwork and air handling spaces are limited to short runs for specific purposes, but better cables (e.g. MC and plenum rated cables) can have longer runs under model codes as the risk for fire spread and toxic fumes isn't great.
I don't think it really matters if ya call parts of duckwork either a "duct" or "plenum" unless you are debating very fine points of the NEC which is not what we are really talking about here.
--
Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee
I am absolutely amazed sometimes by how much thought goes into doing things wrong
Originally Posted By: jpeck
This post was automatically imported from our archived forum.
| roconnor wrote: |
| I dont agree that wiring is "equipment", |
It is your right to disagree, but you are disagreeing with the code (by definition - wiring is "equipment").
You can also say you think it is butter, but the code defines it as "equipment". 
I have no problem with whatever you want to call it. I am just reporting what the code says.
--
Jerry Peck
South Florida
Originally Posted By: roconnor
This post was automatically imported from our archived forum.
Wiring will obviously form a “part of” electrical equipment, but it doesn’t mean wiring is “equipment”. Also, NEC 300.22.B (as well as other sections of the NEC and model building codes like the IBC that incorporate the NEC) have clearly separate provisions for “wiring” and “equipment” …
I can see where you are going with a literal interpretation of the code, but it's just not a practical application of those provisions. If we are really talking about the finer points of the NEC and definitions, maybe it can be kicked around on MH's board.
Did you come across a situation in a home inspection where this became an issue?
--
Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee
I am absolutely amazed sometimes by how much thought goes into doing things wrong
Originally Posted By: jpeck
This post was automatically imported from our archived forum.
| roconnor wrote: |
| Did you come across a situation in a home inspection where this became an issue? |
Nope, it was discussed and explained when I (and four others) were working with Mike Holt on his new video for the 2005 NEC code changes. Very interesting.
--
Jerry Peck
South Florida
Originally Posted By: Greg Fretwell
This post was automatically imported from our archived forum.
I admit I haven’t really studied the changes but isn’t the only real change to 300.22(B) the deletion of liquidtite FMC as an approved method?
Originally Posted By: roconnor
This post was automatically imported from our archived forum.
| Greg Fretwell wrote: |
| ... isn't the only real change to 300.22(B) the deletion of liquidtite FMC as an approved method? |
That was my understanding too ... CLICK HERE ... see ROP 3-93 and 3-94
Also note that 300.22 states that section applies to both "wiring and equipment" ... so if wiring is "equipment", then both would not be listed ... 
Getting a little deep here though.
--
Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee
I am absolutely amazed sometimes by how much thought goes into doing things wrong
Originally Posted By: bbadger
This post was automatically imported from our archived forum.
I sure am not going to worry about this one, I will continue to run FMC in ducts and or plenum’s when necessary.
Here is another example
| Quote: |
| Service. The conductors and equipment for delivering electric energy from the serving utility to the wiring system of the premises served. |
Why bother with the word conductor when equipment is already there?
IMO the NEC, regardless of what the definition says, regards wiring as separate from equipment.
But put in a proposal. 
by Jerry
| Quote: |
| This is not a trap. This is simply something I found out and am sharing. |
Come on Jerry go back and read the thread you where laying out the 'cheese' to catch someone up.
Nothing wrong with that, but don't try to BS us.
Bob
--
Bob Badger
Electrical Construction & Maintenance
Moderator at ECN