Low voltage splices in plenum.

[5 S electric]

Hello,

We are installing controls for an hvac project on our campus. We will be installing automated logic controls belimo water valves, and some lab air valves. My question is do the low voltage splices need to be in a box. All valves controllers and wire are plenum rated.

Thanks for your time.

 

[anthonysolino]

Hello,

We are installing controls for an hvac project on our campus. We will be installing automated logic controls belimo water valves, and some lab air valves. My question is do the low voltage splices need to be in a box. All valves controllers and wire are plenum rated.

Thanks for your time.

it depends on what class the wiring method you are using is. you will have to go in to art. 725 in think then dive in to your classes to see what wiring method applies to you!

 

[hbiss]

it depends on what class the wiring method you are using is. you will have to go in to art. 725 in think then dive in to your classes to see what wiring method applies to you!

Well, I think the OP indirectly stated that he is running either CL2P or CL3P wiring because he said the wiring is plenum rated. No conduit, just open wiring through the ceilings. In that case there is no requirement for splices to be contained in boxes.

-Hal

 

[GoldDigger]

Well, I think the OP indirectly stated that he is running either CL2P or CL3P wiring because he said the wiring is plenum rated. No conduit, just open wiring through the ceilings. In that case there is no requirement for splices to be contained in boxes.

-Hal

But there is still a chance of fully open splices being damaged if someone later drags new cabling over them. At least taping each splice point seems conservative to me.

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[anthonysolino]

I agree with Hal, from what I read you can unfortunately throw it in the ceiling.

 

[hbiss]

But there is still a chance of fully open splices being damaged if someone later drags new cabling over them. At least taping each splice point seems conservative to me.

Sure. I would never just leave the splice junction hanging or flying in the breeze. At least grab all the cables feeding the splice in your hand, double it back and ty-rap to all together so that if a cable is pulled on it won't pull on the splice. Better still is to ty-rap to a support if available.
-Hal

 

[hbiss]

Navigating the requirements in the National Electrical Code (NEC) for ducts, plenums, and other air-handling spaces can be difficult. Air-handling systems have the potential to convey smoke, hot gases, and flames from one area of a building into another.

Not difficult at all.

-Hal