Patrick Costelloe holds a C10 Electrical License and a BS in Mechanical Engineering. After spending 8 years working as an industrial electrician, he completed a degree in mechanical engineering. Following that he worked as a project engineer designing, installing and troubleshooting large filtration equipment in the chemical and mining industries. He is the holder of a number of patents. He currently lives in San Francisco and can be reached at


Patrick's Latest Articles

  • Klein MM5000 Multimeter

    The made in the USA Klein multimeter MM5000 is well constructed and provides the key measurement functions required by an electrician.