Wruderman79
Member
- Location
- Ny,Ny,USA
Is there a code reference for supporting low voltage cables for hvac to the hvac unit itself ive seen a lot of times conduits attached to the ribs of ducts is this legal?
Low voltage cable support
- Thread starter Wruderman79
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gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
That section is not quoted in 725 or 760, and so does not apply. These sections state that only those portions of 300 quoted within them apply to them.
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Not really correct, that is for class 2 cables attached to conduit that serves HVAC or such. Not conduits to HVAC duct work.
(2) Where the raceway contains power supply conductors
for electrically controlled equipment and is used to support
Class 2 circuit conductors or cables that are solely
for the purpose of connection to the equipment control
circuits
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Not totally relevant, the question is the support of conduits off duct work, it is irrelevant if those conduits contain power or control wiring.
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
If your question is: "Is it allowed to attach conduits to the ribs of duct work", the answer would be based on if the duct work is rated and installed to hold the additional weight.
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
I think what the OP is asking is if it's permitted to use ductwork to support conduits and wiring if the conduits and wiring are part of the HVAC system. My answer would be no. Other than whips to connect motorized dampers for instance, the wiring is no different than any other and must be supported independently.
-Hal
-Hal
Horizontal I would agree, but if its coming down the side to the furnace vertically, i would think it would be ok, but that is JMO.
there are times when walls for support are too far from furnace, i am talking resi, (furnaces are placed in the center of an unfinished basement)
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
He's not talking about that kind of situation, he's refering to HVAC duct work above ceilings. In your case I see no problem, we all do that. The conduit is there to supply the furnace.
-Hal
....would you say the same thing for disconnects associated with a hvac system?
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
"The disconnecting means shall be permitted to be installed on or within the air-conditioning or refrigeration equipment."
Like I said above about boilers and furnaces in the basement. Locating the disconnect on the equipment (boiler, furnace or air-handler) is permissable. On the ductwork it's not.
-Hal
Like I said above about boilers and furnaces in the basement. Locating the disconnect on the equipment (boiler, furnace or air-handler) is permissable. On the ductwork it's not.
-Hal
bcunning
New member
- Location
- Crystal Lake illinois
Why NEC 300.11(B)(2) does not allow attachment of unrealted conductors to conduits
Why NEC 300.11(B)(2) does not allow attachment of unrealted conductors to conduits
The firm I work for allows it's installer to connect low voltage signal and control cables to conduit at customer's sites. I won't do it per 300.11(B)(2) but my firm says it's a waste of time and it's no harm to do it. I am talking about low voltage witing that is in no way related to thermostat or HVAC control. It may be CAT 5 Ethernet for example. Until I can present a good technical reason not to do it, it will be allowed. Are there any real safety or technical reasons not to do it?
Why NEC 300.11(B)(2) does not allow attachment of unrealted conductors to conduits
The firm I work for allows it's installer to connect low voltage signal and control cables to conduit at customer's sites. I won't do it per 300.11(B)(2) but my firm says it's a waste of time and it's no harm to do it. I am talking about low voltage witing that is in no way related to thermostat or HVAC control. It may be CAT 5 Ethernet for example. Until I can present a good technical reason not to do it, it will be allowed. Are there any real safety or technical reasons not to do it?
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
From what I understand it's because those low voltage cables can interfere with the maintenence of whatever it's hung on. If the LV installer uses the electrical conduit to support his wiring and the electrical conduit is removed by the electrician what is going to happen? It's also possible for LV cables, if there are enough of them, to cause the conduit supports to fail and I have seen 6 and 8" bundles.
You seem to think that your boss has the last word or some say in this. Good reason or not, if your work is inspected you will not be allowed to do it. And believe me, if that happens on a large enough job and you are made to change everything you won't do it again. That the Code prohibits it should be good enough reason.
-Hal
You seem to think that your boss has the last word or some say in this. Good reason or not, if your work is inspected you will not be allowed to do it. And believe me, if that happens on a large enough job and you are made to change everything you won't do it again. That the Code prohibits it should be good enough reason.
-Hal
1.42_tera_dynes
Member
- Location
- Connecticut
Ask the inspector how he wants it and it is correct.
- Status