`Liquid-tight' casing helps to protect wires to A/C unit

The Inspector's Eye

September 02, 2001|By Dean Uhler

A reader recently sent in a question about the wiring to his air conditioner.

He asked what electrical code applies to placing underground 10-gauge, 220-volt wiring that comes out of his home for about two to three feet and goes into the air to his air conditioner compressor outside the home, and whether the wire has to be protected in any manner.

Since the wire was described as being in the air, the use of the term "underground" seems to refer to the wiring type, rather than where it will be placed.

A type of underground-rated wiring commonly used as a feed to exterior condensing units for residential air-conditioning systems is Type "UF" cable. This is flexible, plastic-sheathed cable, usually gray or white.

Since this cable will be exposed to sunlight at the exterior of the house, it must be a type identified as "sunlight resistant."

As for the need for protection of the wiring, the National Electrical Code provides simply that conductors shall be "adequately protected" where subject to physical damage.

The cable you are describing typically extends from the rear wall of the house to the condensing unit two or three feet away, and runs parallel to the refrigerant lines.

Cables in this location often have no special protection provided, presumably because they are sheltered from physical damage by proximity to the condensing unit and its refrigerant lines.

An alternative to "UF" cable, one that in my opinion makes for the nicest installation, is the use of "liquid-tight" flexible nonmetallic conduit to encase the wires to the air conditioner condensing unit. That material is a thick, plastic sort of tubing, usually gray, which is less vulnerable to physical damage than "UF" cable and uses weatherproof connectors at the ends.

Inspector's Eye

Dean Uhler has been a home inspector for more than 12 years and is president of Baltimore-based Boswell Building Surveys Inc. Uhler is a member of the American Society of Home Inspectors (ASHI) and is the treasurer of the Greater Baltimore Chapter of ASHI.

Questions, with name, address and daytime telephone number, about homes and home inspections can be faxed to 410-783-2517, e-mailed to real.estate@baltsun.com or mailed to Inspector's Eye, Second Floor, 501 N. Calvert St., Baltimore, Md. 21278-0001.

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