Running cable thru a range exhaust vent

[HCServices]

A customers old Jenn-Air cook top unit was connected with #10 wire and a 30A breaker. the new unit requires #8 wire and a 40A breaker. The new circuit will be very difficult to route through this two story house. The old, and new, cook top has a powered down draft ventilator system that connects to a 6" PVC pipe embedded in the concrete slab. The venting material embedded in the slab is 60?C schedule 40 PVC and exits out through the side of the concrete slab.

I want to run the new circuit from the panel board outside, through this existing 6" vent, using MC alone or THHW in PVC conduit. This vent is not from a direct flame (furnace or dryer), just smoke and or strong smells, the temperature should not exceed 90?C. the circuit would exit the vent pipe at the top before the powered ventilator flex connection.

Will the Electrical Code allow the new circuit to connect through this embedded vent pipe? What supporting rules can be referenced?
I cannot get a clear answer from my peers and associates. Some report success with this others flat say no.

 

[pete m.]

I would say that 300.22(A) would not allow the proposed method.

Pete

 

[Sierrasparky]

I would say that 300.22(A) would not allow the proposed method.

Pete

I domn't see how that code would apply. This is not a commercial kitchen.

 

[Hv&Lv]

Just by looking at 300.21, I can't see how a convenience duct for a downdraft cooktop would be included in that article, although I am open to any arguments for.
I wonder if 300.21 would be more applicable? (go for it and seal up all holes)

 

[chris kennedy]

1) What does the manufactures install instructions say about foreign systems in their duct?

2) Can you be sure your installation won't compromise the minimum requirements of 2009 IRC T M1507.3, 100cfm intermittent or 25cfm continuous?

 

[Hv&Lv]

1) What does the manufactures install instructions say about foreign systems in their duct?

2) Can you be sure your installation won't compromise the minimum requirements of 2009 IRC T M1507.3, 100cfm intermittent or 25cfm continuous?

I can't see how that requirement can come into play for a convenience duct. This fan doesn't even need to be on. I absolutely hated mine (Jenn-Aire cooktop). The cold air poured in on windy winter days, and it really did no good for heat or smoke removal as it was a downdraft unit. I removed my cooktop and replaced it with a unit that had no downdraft. removed the ductwork and had the flooring contractor patch the hole in the hardwood under the island (yes, I removed the island- sent it to a cabinetmaker to have the holes fixed). Am I now in violation of this code? How about every home that has a cooktop and no downdraft?

 

[chris kennedy]

I can't see how that requirement can come into play for a convenience duct.

If the OP's new cook-top is designed for down draft ventilation, it has to meet the requirements of chapter 15 IRC.

 

[Hv&Lv]

I can't see how that requirement can come into play for a convenience duct. This fan doesn't even need to be on. I absolutely hated mine (Jenn-Aire cooktop). The cold air poured in on windy winter days, and it really did no good for heat or smoke removal as it was a downdraft unit. I removed my cooktop and replaced it with a unit that had no downdraft. removed the ductwork and had the flooring contractor patch the hole in the hardwood under the island (yes, I removed the island- sent it to a cabinetmaker to have the holes fixed). Am I now in violation of this code? How about every home that has a cooktop and no downdraft?

While doing some further reading, I may be glad I did this back in '08 :slaphead:

 

[pete m.]

I domn't see how that code would apply. This is not a commercial kitchen.

I will admit that I stretched a bit but the "jen-air" type downdraft exhaust system will still convey grease laden vapors. 300.22(A), prior to the verbiage about commercial-type cooking equipment, does state that no wiring method shall be installed in a duct used for vapor removal. Since the code is not specific to the type of vapor (although I assume the intent is towards some type of volatile or hazardous vapor) I think grease laden vapors could be included.



(A) Ducts for Dust, Loose Stock, or Vapor Removal. No wiring systems of any type shall be installed in ducts used to transport dust, loose stock, or flammable vapors. No wiring system of any type shall be installed in any duct, or shaft containing only such ducts, used for vapor removal or for ventilation of commercial-type cooking equipment.

Pete

 

[kwired]

Installing anything in the duct will effect how efficiently air flows through it. Ask a good HVAC guy about the performance issues between different types of duct, especially corrugated vs smooth, and how much restriction is added with just 1 elbow.