The examples and perspective in this article may not represent a worldwide view of the subject. (December 2010)
In theatre, the master electrician (or chief electrician in the UK) is responsible for implementing the lighting design for a production drawn up by the lighting designer. This involves overseeing the preparation, hanging, connection and focusing of stage lighting fixtures. 
This can be done on a show-by-show basis, or as a resident position of a specific theatre. The tool of the trade of the theatrical master electrician is the adjustable spanner or crescent wrench, used to secure stage lighting instruments from lighting positions in the theatre. This wrench is typically attached to the belt or wrist with a lanyard, which is important because the master electrician tends to work at great height, from ladders, lift tables, catwalks, or lighting trusses, where a falling wrench may hurt people or damage property below.
The master electrician supervises and is responsible for all other electricians working on any construction or installation project. Only the master electrician can pull the permits with the electrical authority, and they can only be registered with one electrical contracting company at any one time. Other electrical duties performed by any electrician include:
Master electricians go through extensive on-site and classroom training, with work in more formal settings such as schools or colleges. The designation "master" is only given to electricians who can display extensive job knowledge and are tested to have an extensive understanding of the electrical safety code.[ citation needed]
There are no formal certifications of the "theatrical title, master electrician", as there are in some of the more mainstream trades, but in March 2003  ESTA, which merged with PLASA in 2010,  developed a certification process. Those who pass this rigorous test will become ETCP Certified Entertainment Electricians - and will be recognized as the industry's best.  The stagehands union, IATSE, come close in that they offer apprentice and journeyman levels of certification. In the future, IATSE, or some of the larger local affiliations may form a more formal method of certification, which may include the title of master electrician. In the meantime, almost every production, from high school shows to Broadway uses the term to describe their primary electrician, regardless of their skill level or experience.