Running circuit for AC Condenser have questions


Old 03-12-07, 09:32 AM
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Running circuit for AC Condenser have questions

I have to run a 30 amp 220 circuit for an AC Condenser im adding to my house. I have the breaker installed and I have the needed 10 guage nm wire to run through my basement to the area it will penetrate. I have 3 questions.

1. Can I put red tape over the white wire in the NM cable to signify a second load wire or do I need to try to find NM cable with Black/Red and ground?

2. Im installing a junction box before it goes outside so I have a place to run the seal tite to. Am I allowed to connect THHN wire to the NM cable or do I have to stuff the NM cable through the seal tite?

3. The condenser calls for a 30 amp circuit. At my local home center I only see a blade disconnects rated at 60 amps. Is this one ok to install or do I need to match the blade disconnect to the breaker size.
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Old 03-12-07, 09:39 AM
Ed Imeduc's Avatar
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Id check what code there calls for. As to what you can do
Old 03-12-07, 10:04 AM
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The white wire inside NM cable (or UF cable) can be re-identified with a marker. It doesn't have to be red. You can use a black marker, a blue marker, or just about any other color except green or gray.

Before the NM leaves the house it must be terminated. In a junction box you can connect the NM cable to individual conductors. With individual conductors you are not allowed to re-identify the wires, so buy black and green only. THe junction box must remain accessible.

As Ed has stated, check with your inspector to see what they require. They may want more than a 30 amp circuit, and you may need one if a receptacle is required to be installed.
Old 03-12-07, 10:14 AM
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The 60 amp rating of the disconnect is the maximum size it is rated to handle. Since you only need a 30 amp rating you are fine.

Can you bring the NM-B into the back of the disconnect? It would be one less potential point for a splice to fail instead of the junction box.

Do not forget the required 125 volt GFI protected receptacle within 25 feet of the compressor, and at the same grade level.
Old 03-12-07, 07:26 PM
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Before the NM leaves the house it must be terminated. --- ??

The NMB can go directly into the disconnect with approved connectors ( not exposed to the weather). on the load side run the THHN (2 blacks and a green), thru the seal tite to the unit. With approved connectors.

Don't forget the control wires to operate it. These will be in seperate conduit, or free air-- depending on the insulation.

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