The good news... everything doesn't have to be listed. But, (there is always a BUT)... equipment used in the completed installation must be "approved" and appropriate.
110.3 Examination, Identification, Installation, and Use of Equipment.
(A) Examination. In judging equipment, considerations such as the following shall be evaluated:
(1) Suitability for installation and use in conformity with the provisions of this Code
FPN:Suitability of equipment use may be identified by a description marked on or provided with a product to identify the suitability of the product for a specific purpose, environment, or application. Suitability of equipment may be evidenced by listing or labeling.
The last line of the FPN, "Suitability of equipment
may be evidenced by listing or labeling." is the kicker.
The 2002 Handbook gives some guidance for inspectors.
Approval of equipment is the responsibility of the electrical inspection authority, and many such approvals are based on tests and listings of testing laboratories.
I agree with shortcircuit, 90.4 gives the AHJ some latitude. 90.7 also provides for the AHJ to look not only at listing but other data that may indicate that the equipment is acceptable for the intended application. Also,90.7 clearly states that "specific items of equipment and materials" required by the code must be suitable. Not everything in the code is specified, so, it's the AHJ that gets to decide if equipment is suitable if it is not specified by the code. (e.g., staples)
I believe the intent of 110.2 and 110.3 is to ensure that equipment is designed for the application. If it doesn't look right, don't approve it until you do a little more research.
Almost forgot, Article 100 defines "approved."
Approved. Acceptable to the authority having jurisdiction.
The AHJ is da' judge. Here comes da' judge... here comes da' judge
[This message has been edited by safetygem (edited 12-27-2004).]