Life as an interior electrician in the army reserves?

Gil Gonzalez, The MOS you are looking at is 12R. There is a decent thread on Reddit and RallyPoint (links at bottom)

You’ll be taught basic schematic reading, simple electrical theory, identification of basic wiring types and tools. The downside is it really isn't a credentialing MOS like some think. It helps people go from 0-apprentiship on the civilian side, but if you are already a journeyman, depending on your state, your service hours may count towards your license.

The complication is that you will only really get experience if you are in a vertical construction company, and then only on real projects some of the time. I had a couple of those companies that would have projects they would work during Annual Training, and practice on training walls during the Battle Assemblies. Through E4, you are really just doing basic wiring installation.

MOSC 12R10 (E1-E4)
The MOSC 12R10 installs and handles maintenance for interior electrical systems.
These electrical systems in this skill level are up to 600 volts. Also, at this skill level, personnel are responsible for understanding the blueprints and specifications necessary to carry out electrical plans.
Personnel service electrical boxes and panels and install sheathed cable and conduit. Also, testing equipment and ensuring circuits are in good condition are a necessary skill level.

MOSC 12R20 (E5)
For the skill level of MOSC 12R20, personnel is responsible for supervising the installation and maintenance of electrical systems. Also, the skill level requires the ability to coordinate construction planning and advising on electrical construction. Furthermore, the use of equipment to find problems and do repairs is essential.

For Staff Sergeant (E6) the MOS feeds into 12H: Construction Supervisor

https://www.reddit.com/r/Militaryfaq/comments/ip34zr/whats_it_like_being_a_12r_interior_electrician_in/
https://www.rallypoint.com/answers/anyone-with-specific-information-experience-about-the-12r-mos

Better to be a civilian contractor to the military

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https://rellaelectric.com/