We just bought a Chicago-area house and found that there's no ground wire in some of the recently re-wired areas. I thought that the national electrical code requires a ground wire for new construction and remodels, as opposed to relying on the steel conduit as ground. Is this correct?
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Conduit (RMC, IMC or EMT) is an NEC-accepted ground path. So, if the wires are in steel conduit, no OTHER ground wire is required.
If that gives you concerns, you might find this link reporting research into the effectiveness of conduit as a ground relieves them.
Updated link to NEMA Technical Services Department Bulletin 97.
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National Electrical Code does allow metallic conduit and tubing to be used as an equipment grounding conductor, as long as it's installed properly.
However, before using it as such in an existing installation, you should verify that it provides an adequate continuous path to ground.
National Electrical Code 2014
Chapter 3 Wiring Methods
Article 342 Intermediate Metal Conduit: Type IMC
342.60 Grounding. IMC shall be permitted as an equipment grounding conductor.
Article 344 Rigid Metal Conduit: Type RMC
344.60 Grounding. RMC shall be permitted as an equipment grounding conductor.
Article 348 Flexible Metal Conduit: Type FMC
348.60 Grounding and Bonding. If used to connect equipment where flexibility is necessary to minimize the transmission of vibration from equipment or to provide flexibility for equipment that requires movement after installation, an equipment grounding conductor shall be installed.
Where flexibility is not required after installation, FMC shall be permitted to be used as an equipment grounding conductor when installed in accordance with 250.118(5).
Where required or installed, equipment grounding conductors shall be installed in accordance with 250.134(B).
Where required or installed, equipment bonding jumpers shall be installed in accordance with 250.102.
Article 350 Liquidtight Flexible Metal Conduit: Type LFMC
350.60 Grounding. Grounding and bonding for LFMC shall be installed in accordance with 350.60(A) and (B).
(A) If used to connect equipment where flexibility is necessary to minimize the transmission of vibration from equipment or to provide flexibility for equipment that requires movement after installation, an equipment grounding conductor shall be installed.
Where flexibility is not required after installation, LFMC shall be permitted to be used as an equipment grounding conductor when installed in accordance with 250.118(6).
Where required or installed, equipment grounding conductors shall be installed in accordance with 250.134(B).
Where required or installed, equipment bonding jumpers shall be installed in accordance with 250.102.
(B) Where Air Conditioning or Refrigerating Equipment is installed outdoors, an equipment grounding conductor per 250.118(1) shall be provided within the raceway and shall be sized per 250.122.
Article 358 Electrical Metallic Tubing: Type EMT
358.60 Grounding. Grounding and bonding EMT shall be installed in accordance with 358.60(A) and (B).
(A) EMT shall be permitted as an equipment grounding conductor
(B) Where Air Conditioning or Refrigerating Equipment is installed outdoors, an equipment grounding conductor per 250.118(1) shall be provided within the raceway and shall be sized per 250.122.
Article 360 Flexible Metallic Tubing: Type FMT
360.60 Grounding. FMT shall be permitted as an equipment grounding conductor where installed in accordance with 250.118(7).
