Wiring in cold air return duct?

[helluva_pack]

Was hoping someone could provide some expert thoughts on pulling electrical wiring through a cold air return duct.

Basically, does this meet code?

I'm trying to get some pot lights installed in my second floor ceiling. However, it's a split level house, and the room is open to above (~12 ft high). The way the house is laid out, there are no inner walls that directly connect from the attic to the basement to pull the electrical wire.

Several contractors (licensed electricians) have said that electrical wiring can be pulled through the air return ducts, so it won't be a problem - that is, no need to punch holes through the walls (well, one guy says making holes was a must, but he wanted to put holes everywhere!).

I'm wondering if anyone could tell me if this is actually allowed (ie up to code) and/or safe?

I've read somewhere the it has to be armored, and not the standard, NM (non-metal) wire, but couldn't confirm this...

Thanks.

[MacGyver]

Yes, it's OK. You just can't have junction boxes in the duct.

Do yourself a favor - go to Home Depot and pick up a copy of the Electrical Code Simplifed. You can find it in the electrical department. The detail is on page 51 of my 2007-2010 Ontario version.

[nornet]

Yes, it's OK. You just can't have junction boxes in the duct.

Do yourself a favor - go to Home Depot and pick up a copy of the Electrical Code Simplifed. You can find it in the electrical department. The detail is on page 51 of my 2007-2010 Ontario version.

+1 It's the best $12 I ever spent. Wish they had one for plumbing.

[dgmorr]

+1 It's the best $12 I ever spent. Wish they had one for plumbing.

I was just about to ask if they did....guess not?

[Munchos]

Perfectly fine and usually its the only way to run wire in a basement that is completely finished with drywall, without having to put holes anywhere.

And why are you asking people who don't specialize in trades to know if this is correct? Especially when you have a qualified electrician(s) tell you it is ok. There is a lot of bogus information on this site by people who think they know what they are talking about but are wrong. I know I would take the advice from a professional over advice given to me over the internet by some weekend diy's who think they know it all.

[MMMM]

And why are you asking people who don't specialize in trades to know if this is correct? Especially when you have a qualified electrician(s) tell you it is ok. There is a lot of bogus information on this site by people who think they know what they are talking about but are wrong. I know I would take the advice from a professional over advice given to me over the internet by some weekend diy's who think they know it all.

Probably because so many people have had so many issues with professional qualified trades people. I hired an electician to wire my wifes physio clinic. Watching the so called professionals pull wire was painfull. Yes there is a need to hire a qualified Electrician. We needed to move the main on the house. So we called in a professional. They screwed it up. My lawyer was called and fixed the issue promptly:cheesygri. Remember folks, take pictures of everything your so called professional does.

Tile Contracters: had to turf the lot during a restaurant reno.

Hvac: Still not sure where all my hard earned cash went during our clinic reno.

Roofing: Figured we could do it ourselves. Once up on the roof I remembered my fear of heights. Had my wife finish the roof. It took a few extra days and she did a great job:D.

My wife and I gutted our house this fall. We had quotes from 3 electrical companies. We decided to do the work ourselves. In Alberta you can pull an homeowners permit and we passed the inspection no problem.

During the last few years in Alberta it was damn hard to find a decent contracter to do the work needed. often the skilled individual was busy running the business while the hired apprentices were doing the grunt work. Things have changed. Lots of contracters looking for work now. Prices are comming down. Hopefully the quality of work improves allso.

There may be a lot of bogus information on this site but there is a lot of helpfull information given by well informed people. And just a quick note, I am a qualified journeyman:!:

[helluva_pack]

Thanks, everyone, for your replies. I'll have to go get the code from HD!

The reason I ask here, is that, as MMMM indicated, some "professional" contractors just aren't any good!

Some tell you things they think you want to hear in order to get the job (one guy tried to tell me he provides "special" bulbs with his pot lights, which are great quality - of course, they're just the ones that come with the fixture).

On this forum, I can get an unbiased, objective view. Granted, it's possible that someone may try to mislead me or may not know, but I've found that there is generally good information from knowledgeable people (again, as MMMM mentioned). It's just another avenue of feedback.

Every search I've found, seemed to indicate armored cable only - but I wasn't sure if that was US only, or in Canada as well. I didn't know I could get a copy of the simplified code from HD - until now!

Anyway, thanks again, everyone!

[trucanuck]

Well I have some in my ducts - didn't know it was code - it was the previous owner ... glad to hear it's up to code.

[Drthorne]

Well I have some in my ducts - didn't know it was code - it was the previous owner ... glad to hear it's up to code.

as long as it's not in a heating duct that deliverys warm air to the rooms from the furnace :cheesygri

[deep]

I'm going to have to grab a copy of that book (unless some kind soul wants to scan the page in question ;)) because I was under the impression that wiring was not permitted in any ductwork or cold air return. It would certainly make life easier if that was not the case.

[l69norm]

I'm going to have to grab a copy of that book (unless some kind soul wants to scan the page in question ;)) because I was under the impression that wiring was not permitted in any ductwork or cold air return. It would certainly make life easier if that was not the case.

+1, I had the same impression as the OP - NMD90 is allowed to go across a cold air return, but not run along the inside a cold air return.

We have to use special LAN cable for runs along the inside of an air return (i.e. FT6 vs. FT4), so I'm surprised that regular electrical wiring is allowed.

[deep]

+1, I had the same impression as the OP - NM90 is allowed to go across a cold air return, but not run along the inside a cold air return.

We have to use special LAN cable for runs along the inside of an air return (i.e. FT6 vs. FT4), so I'm surprised that regular electrical wiring is allowed.

That was exactly what I had read - that you could go perpendicular to the direction of air travel, but not along the duct. If I get off my ass and buy the book, I'll follow-up on this. If someone else can beat me to it, thanks!

[trucanuck]

as long as it's not in a heating duct that deliverys warm air to the rooms from the furnace :cheesygri

Cold air return. It's in the topic so I didn't specify. Mine goes perpendicular THROUGH the cold air return at one point in the basement. It is not run along it.

[l69norm]

I found the some details in the Ontario Building Code:
http://www.e-laws.gov.on.ca/html/regs/english/elaws_regs_060350_e.htm

3.6.4.3. Plenum Requirements

(1) A concealed space used as a plenum within a floor assembly or within a roof assembly need not conform to Sentence 3.1.5.15.(1) and Article 6.2.3.2. provided,

(a) all materials within the concealed space have a flame-spread rating not more than 25 and a smoke developed classification not more than 50, except for,

(i) tubing for pneumatic controls,

(ii) optical fibre cables and electrical wires and cables that exhibit a flame spread not more than 1.5 m, a smoke density not more than 0.5 at peak optical density and a smoke density not more than 0.15 at average optical density when tested in conformance with the Flame and Smoke Test in the Appendix to CAN/CSA C22.2 No. 0.3, “Test Methods for Electrical Wires and Cables” (FT6 Rating),

(iii) optical fibre cables and electrical wires and cables that are located in totally enclosed noncombustible raceways,

(iv) totally enclosed nonmetallic raceways that exhibit a horizontal flame distance of not more than 1.5 m, an average optical smoke density of not more than 0.15, and a peak optical smoke density of not more than 0.5 when tested in conformance with the Test for Flame Propagation and Smoke Density Values in Section 3.3 of the ULC/ORD-C2024, “Fire Tests for Optical Fibre Cable Raceway” (FT-6 Rating), and

(v) single conductor electrical wires and cables that exhibit a vertical char of not more than 1.5 m when tested in conformance with the Vertical Flame Test —Cables in Cabletrough in Clause 4.11.4. of CSA C22.2 No. 0.3, “Test Methods for Electrical Wires and Cables” (FT4 Rating), and

(b) the supports for the ceiling membrane are of noncombustible material having a melting point not below 760°C

It seems to me that the wiring has to be FT6 rated. Regular NMD90 is FT1

Regular wiring has to run in a sealed metallic conduit. The alternative for regular wiring is totally sealed plastic conduit that is FT6 rated.

[nornet]

hulluva pack Could you add your location to your profile? Many people have quoted the Ont elec code which may or may not apply. After several posts I see you are in AB.

[loudsubz]

anytine you run in an air return the wire has to be ft6 (plenum)

the difference between the FT rating is how fast the wire burns in a fire. FT6 will travel much slower.

FT RATINGS Flame test ratings indicate how readily fire will spread along wire and cable. The tests are a complex formula of time, distance, diameter, and set-up; but the following gives a general idea of what happens.
FT1 A bunsen burner flame is applied to a vertical sample for five 15 second applications. Burning must cease within 60 seconds of removal of the burner, with no more than 25% of a paper indicator charred. FT1 is applicable for wires such as NMD90 and TW75 which are used in combustible buildings. UL VW1 is similar to CSA FT1.

FT2 A bunsen burner flame is applied to a horizontal sample for five 15 second applications. The charred portion must not exceed 100mm from end to end, and there shall be no flaming particles dropping from the sample. Products such as some S, SJ and HPN cords, as well as SIS wire, are rated FT2.

FT3
This rating has been deleted.
FT4
Cables are strapped to an 8-foot vertical section of ladder tray and burned at 70,000 BTU for 20 minutes. The charred portion shall not exceed 1.5 meters. The FT4 test is used on cables intended for tray or shaft applications. The CSA FT4 test is similar to UL1581 paragraph 1160, but FT4 is more stringent. FT4 cables can be used in non-combustible buildings. Nexans Teck90, RA90 Corflex and ACWU90 are FT4 rated.


FT5 Flame is applied to a horizontal sample, similar to the FT2 fire test but with a much larger burner. The flame must extinguish in less than 4 minutes and the burn length shall not exceed 150mm. The FT5 test is applicable to portable cables used in underground work areas such as mines and tunnels.

FT6 Cable samples on a horizontal tray in a tunnel type of chamber are burned at 300,000 BTU for 20 minutes. Flame spread not to exceed 1.5 meters, with a smoke density during the test of (a) 0.5 peak; and 0.15 maximum average. FT6 is used for cable in return air plenums. The CSA FT6 test is similar to NFPA 262-1985 and UL S102.4. No CSA FT6 rated power cables are presently available in Canada. Some provinces allow FT4 single conductor cables to be used in these locations. Otherwise, cable in conduit is the permitted installation method in return air plenums.
AG14
AG14 refers to the acid gas given off during burning of plastics used in cable. Normal PVC would produce approximately 30%, by weight, of acid gas during combustion. AG14 indicates materials will produce less than 14% acid gas during combustion. Nexans Teck90, RA90 Corflex and ACWU90 all have insulation and jacket materials rated AG14.

[l69norm]

.....No CSA FT6 rated power cables are presently available in Canada. Some provinces allow FT4 single conductor cables to be used in these locations. Otherwise, cable in conduit is the permitted installation method in return air plenums. ...

I think that summarizes it....

[helluva_pack]

hulluva pack Could you add your location to your profile? Many people have quoted the Ont elec code which may or may not apply. After several posts I see you are in AB.

I'm in the GTA (Ontario).