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Alex, Master Electrician
Category: Electrical
Satisfied Customers: 1750
Experience:  Owner of independent electrical contracting company. Licensed Electrical Contractor in CT.
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Hello, I am running electrical wire from my air conditioner

Customer Question

I am running electrical wire from my air conditioner heads to the condenser on the roof. This is in a restaurant with a suspended ceiling. I notice that all the electrical wire running above the suspended ceiling is encased in a grey/metal flexible sheathing or conduit material. What is the reason for this? In a residential home, normal 14-2 wire is ran above suspended ceilings and attics with out this flexible conduit? The wire that came with the air conditioning units is just a normal wire without any flexible conduit. Does it need to be? Or do I have to run this wire in some rigid or flexible conduit?
Submitted: 3 years ago.
Category: Electrical
Expert:  Alex replied 3 years ago.
Hello and Thank you for posting on My name is XXXXX XXXXX I'm here to help you.

The reason is that the wires ran in suspended ceiling in commercial need to be plenum rated . That wire with the flexible metal sheath is MC cable which is rated for that. If you are running line voltage wires ( 120/240/277 volts ) they need to be MC or THHN wires in the emt pipe. If you are running low voltage wire then it needs to be plenum rated.
Now if you are installing split unit ( Mitsubishi or so ) then I believe interconnection in between is line voltage 3 wires. If that so you will need to run 12/3 MC with black, red, white and green )

Let me know if that did not answer your question and I will do my best to do so.
Customer: replied 3 years ago.

ok, I am a little bit confused. I am not sure exactly the difference between line voltage wire and low voltage wire? Is the line voltage wire, the wire that would run from the electrical panel to the condenser? So, is the low voltage wires the wires ran from the condensor to each air handler?

The wires running to each air handler are a 3 wire.


Can a pvc conduit be used?

Expert:  Alex replied 3 years ago.
Line voltage is 120, 208, 240 or 277 volt wires. Low voltage is from 9 up to 24 volt wires. I'm not sure what your system has between condenser and air handler ( you will need to check in the manufacturer provided literature what voltage is interconnection between them.

As far as the PVC, in most of the cases you can use PVC although some local codes restricts using PVC . For example in the city of New York the PVC must not be used.

What gage and type of wire came with units?
Customer: replied 3 years ago.

The wires that came with the unit are a 4x16AWG wire. The wire has a black jacket on it. The description online appears that it has a PVC coated jacket? Does this mean it is rated for outdoors?


I was gonna swap this out for an MC wire because it will be running above my suspended ceiling. Or can I just run this 4x16AWG bare in the suspended ceiling?


The unit I am installing is a multi zone, 3 headed mini ductless split air conditioner. I have all the heads mounted and the condensor in place, but I want to run the electrical lines from the air handler heads to the condenser and just up in the air of what I should do, If I can just run these bare 4x16AWG wires or swap it out for an MC wire?


If I swapped it out what gauge MC wire do I need?

Expert:  Alex replied 3 years ago.
The PVC coated is good for outdoors. The best is to try and get the manufacturer name and other writings from the wire and see if its plenum rated. If its plenum rated (which i do not think it is) then you are ok with running it in suspended ceiling..

As far as the MC you could use 14/4 . You could try and get 16/4 MC but its very uncommon wire so it might take time to get it. Electrical supply house should have 14/4.

Let me know if you have more questions.

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