I hear it often that the inspector is making a contractor produce a listing for a product. Then the contractor asks where does it state that a product has to be listed. In our Code NFPA 70 2011 Ed.article 110.2 states that “conductors and equipment shall be acceptable only if approved”. So where does the approval requirement come from? It comes from OSHA. OSHA requires that in general all electrical equipment is to be listed and labeled. You can click or copy the link below to the OSHA site bulletin that gives the information on listing and approval of electrical equipment. In the bulletin it states that 29 CFR 1926.403(a) requires a testing laboratory approval of electrical equipment. So an inspector asking for this listing is his or hers way of making sure that the equipment is approved and being used in accordance with its listing.
When a inspector comes across questionable equipment it is his/her way of making sure the equipment can in fact be used in this installation. They do not have the time to check out the equipment to see if it is safe. When non-listed equipment is used or slips by an inspection, you put the public at risk. To save a few bucks and put people at risk is one of the reasons we have OSHA in the first place. Protecting the public! My job and your job is to deliver a safe working electrical system, not compromised by sub-standard equipment. So the next time you are asked for a listing the inspector must see something that makes him/her question the installation.
https://www.osha.gov/dts/shib/shib021610.html
Take the time to read the bulletin a see why and how equipment becomes approved and listed.
till next time work safe and be safe
Jake