DIY Home Improvement, Remodeling & Repair Forum > Appliances > HVAC > Air Handler in the attic Question




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Old 04-16-2013, 03:43 PM  
kok328
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Unfortunately, installers are not electricians and will not assume liability for installing the disconnect.
Nothing special about a disconnect, don't let the terminology scare you. This is also known as a "service switch". It is just a light switch to cut power to the air handler for when repairs/maintenance is needed. If you interupt the two hot terminals with a switch, it will kill power but, the absence of a neutral makes me think that this is not the circuit that is powering the air handler. As far as needing an outlet, I don't know why they are requiring one but, it will require a neutral.


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Old 04-16-2013, 04:37 PM  
CallMeVilla
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Disconnect is a good idea -- and its CODE -- because it helps proect you when servicing is needed. Here is a short explanation: http://www.eaton.com/Eaton/ProductsS...ects/index.htm

Here is a briefing on the details of installation:

Good luck!


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Old 04-16-2013, 05:00 PM  
kok328
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Quote:
Originally Posted by CallMeVilla View Post
Disconnect is a good idea -- and its CODE -- because it helps proect you when servicing is needed. Here is a short explanation: http://www.eaton.com/Eaton/ProductsS...ects/index.htm

Here is a briefing on the details of installation: http://www.youtube.com/watch?v=REw7JT4d0J4

Good luck!
Good video, I thought he was seeking advice on a disconnect for the air handler not the compressor unit.
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Old 04-16-2013, 07:10 PM  
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Yes, the air handler is correct. they said it was a 220v AHU, i would need a double breaker and a double pole switch. I code Mass Code is that an outlet is required near the unit along with a switch for servicing. The outlet must be a separate line.

I put in a yellow 12-2 romex as they said they only needed a 20amp line. Now I have a line from the panel to the AHU but its not hooked up.

I'll have to buy a metal box to mount to the AHU with a switch for the power. they said since its 220 that theres no neutral. news to me
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Old 04-17-2013, 09:59 AM  
CallMeVilla
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Your post confuses me now. I have never seen a 220 VAC run with #12 wire. What is the gauge of wire feeding into the disconnect? He told you the line is only 20A ?? Are you setting up what is commonly called an "appliance plug" (not with #12!)? You had better check the installation instructions before finalizing this.

If you are doing an appliace plug, then the picture below would apply. A neutral would be used. But not with #12 wire.

However, the lack of neutral IS how it is done in AC applications where 220 VAC is required. ONLY IF your setup (per instructions) does NOT require a neutral would the following apply.

The bare copper wire is the ground wire which needs to be connected to the green wire in the disconnect. This may be a lug or screw connection depending on the manufacturer. In either case the ground wire is connected in your service panel to the ground buss.

The other two wires supply the 220 VAC. If you use either 10/2 or 8/2 cable you will have a white, black and copper wire in the cable sheath. The white wire should be taped with black tape to designate it as a HOT wire. (This tape flag is done at the main service panel and the disconnect to ensure proper identification) It is NOT a neutral. It will be connected to one of the power lugs in the disconnect. The remaining BLACK wire will be connected to the other power lug.
220 VAC DIAG.jpg  
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Old 04-17-2013, 06:20 PM  
kok328
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If you need 220V, I assume this is an electric heater, not gas.
With this new information, I think they want a disconnect without the plug and the AHU would be hardwired to the disconnect.
This setup would not requre a neutral.
They are also asking for a 120V outlet to be used as a "service" outlet.
The amp ratings for AHU will determine the AWG of wire to run (most likely not 12/2). Can you provide the amp rating for the AHU?
12/2 is correct for a 20A service outlet.


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