Question
I would like some advice and general guidance regarding the use of breakers that are not listed on the panelboard data sheet. Some of these panels have not been made in twenty years and the company is out of business. I generally recommend finding surplus breakers on the internet. Most electricians try to get by with breakers that physically fit and if those are rejected, they might get a “classified” breaker. My understanding is that the “classified” breakers are listed for use in specific panels (which is not disclosed in the marketing literature). Am I correct in believing that unless the breaker is listed for use in the specific panel that it is to be used in, it does not meet the code requirement of listed and labeled? — J. C.
Answer
First, it is understandable that for older panelboards it is difficult to find new or replacement circuit breakers. Typically, the panelboard may be obsolete, the manufacturer may be out of business or perhaps purchased by another manufacturer. In addition, electrical equipment design and manufacturing technologies change. As a result, the equipment is not produced or there is little demand for such equipment.
Second, it is imperative to note that it is not good to encourage the use of “surplus breakers” or “breakers that physically fit.” Doing so could create a potentially unsafe condition. Obviously, it is difficult to determine the operating condition of a surplus circuit breaker, and simply because a circuit breaker fits in a panelboard does not make it correct for installation and use. Since safety is paramount in any electrical installation, the installation and use of appropriate equipment is necessary!
Third, as you have noted, classified circuit breakers are intended for installation and use in specific panelboards. Such circuit breakers should be marked or information should be provided to indicate the specific panelboards in which they can be installed. If the circuit breaker is not marked or the information is not provided, it is necessary to contact the circuit-breaker manufacturer. The manufacturer should be able to provide such information and it should be readily available.
As a general note, be aware that some circuit breakers are classified only and others are listed and classified. Generally, classified-only circuit breakers are limited to 15- and 20-amperes, 120/240-volts, and a maximum 10,000-ampere short-circuit current rating; they are intended for use in panelboards with a maximum 225-ampere rating. Although not obvious, there is a difference between listed and classified products.
Last, an article in Underwriters Laboratories The Code Authority, 2007 Issue 1, “Molded Case Circuit Breakers,” written by Warren Shilling, provides a good explanation for listed and classified circuit breakers. The article can be viewed at:http://www.ul.com/tca/issues/tca_issue_1_2007.pdf. — Lanny McMahill, CMP-1