Rough service

A trouble light, also known as a rough service light or inspection lamp, is a special lamp used to illuminate obscure places and able to handle moderate abuse. The light bulb is housed in a protective cage and a handle that are molded to form a single unit. It has a long power line for distant reaching; the handle may also have electrical outlet on it, allowing the light to also double as an extension cord.

Trouble lights are usually powered by AC wall current, but some are powered by a 12-volt source, such as a car battery. The bulb of the trouble light typically has a heavy filament to withstand dropping. It is also referred to as a drop light.[1]

Trouble lights are intended to be used with "rough service bulbs", a form of incandescent light bulbs which are designed with as many as five support wires holding the filament to allow it to withstand heavy vibrations or movement. Lower voltage bulbs such as those intended to function with 12 volt power supplies also have a higher lumen output per watt of power consumption. Compact fluorescent lamps and recently, light-emitting diodes may also be used in trouble lights.

Trouble lights intended for use in hazardous areas such as in petrochemical plants will have features designed to prevent ignition of flammable gas around the lamp, such as heavy sealed lamp enclosures and guards to protect lamps from breaking.


Trouble lights are often used by automotive mechanics and electricians where localized light is needed where ambient light proves to be insufficient.[2]

Trouble indicator

Another use of the term "trouble light" is an indicator for faults in a system, such as an automotive Idiot light or a warning light of any kind, such as a Service Engine Soon light.


This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.