Missouri licensing answer: Missouri has an optional statewide electrical contractor license, but a single official statewide specialty exam named “Sounds, Signaling and Communications Systems” was not verified. Communications and low-voltage specialty licensing can depend on the city or county where you work.
Missouri's electrical licensing structure combines an optional statewide electrical contractor license with local specialty licensing. State law requires political subdivisions to recognize the statewide electrical contractor license, while local governments can continue issuing communications contractor and other specialty licenses.
That means candidates should identify the exact Missouri jurisdiction before relying on any single exam outline. St. Louis County, Kansas City and Jefferson County all provide useful examples of how communications and low-voltage licensing can differ.
Statewide answer: Missouri has an optional statewide electrical contractor license, but the official statewide exam list does not identify a specialty examination titled Sounds, Signaling and Communications Systems.
St. Louis County example: Electrical Communication and Sound | 40 questions | 2 hours | 70% passing | open reference.
Kansas City example: Electrical Contractor Class III covers low-voltage communications and related systems; published testing includes the 50-question ICC G21 Low-Voltage exam.
The course itself remains useful for technical preparation because it covers sound, signaling, alarms, low-voltage communications, NEC concepts, practice questions and test-taking strategy. Candidates should pair the course with the exact rules for their local Missouri jurisdiction.
There is no single verified statewide specialty blueprint, so this table separates the strongest official local examples.
| Jurisdiction / Path | What It Covers | Published Exam / Rule |
|---|---|---|
| St. Louis County Electrical Communication and Sound | Telephone, data, intercom, CATV and related communications systems | 40 questions | 2 hours | 70% | Prov |
| Kansas City Electrical Contractor Class III | Communications, fire alarm, burglar alarm, remote control, low-energy power, signal systems and sound recording | Local contractor license with electrical supervisor / master structure |
| Kansas City G21 Low-Voltage Electrician | General knowledge, alarms, communications and sound, control circuits and fiber optics | 50 questions | 3 hours | open book |
| Jefferson County Communications Contractor | Low-voltage communications, alarms, PA, sound, telephone, data, card readers, CATV and related systems | Approved exam at 70% or better; 3-year contractor license |
| Missouri Statewide Electrical Contractor | Broader statewide electrical contracting credential | Approved nationally accredited electrical exam required; not a dedicated communications specialty exam |
Because Missouri communications licensing can be local, the correct licensing path begins with the jurisdiction where you plan to work.
Step one: identify the city or county that regulates the low-voltage or communications work.
Step two: confirm the exact contractor classification, qualifying-person or supervisor requirement and approved examination.
Step three: use the jurisdiction's current exam bulletin to confirm code edition, reference books, question count and passing score.
Statewide option: Missouri also offers an optional broader statewide electrical contractor license, which is separate from local communications specialty credentials.
These bars use the published 40-question St. Louis County Prov blueprint as a clearly labeled local example, not as a statewide Missouri blueprint.
Reference books vary by jurisdiction. Always use the current bulletin for the exact local exam.
| Jurisdiction / Exam | Reference | Published Use |
|---|---|---|
| St. Louis County Communication and Sound | National Electrical Code | 2017 NEC |
| St. Louis County Communication and Sound | American Electrician's Handbook | 17th Edition |
| Kansas City G21 Low-Voltage | National Electrical Code | 2017 NEC |
| Kansas City G21 Low-Voltage | Ugly's Electrical References | Supporting electrical reference |
Start with the jurisdiction, not the course title. Then confirm the local license, exam, references and contractor requirements before scheduling.
Determine the Missouri city or county that regulates your communications, alarm, data, sound or low-voltage work.
Look for communications contractor, low-voltage contractor, Class III electrical contractor or another jurisdiction-specific title.
Confirm the testing provider, question count, time limit, passing score and content outline.
Use the exact NEC edition and supporting books listed in the current local bulletin.
Practice alarms, sound, broadband, data, telephone, CATV, control circuits, fiber optics, grounding and wiring methods.
Train to locate NEC articles, tables, definitions and communications requirements efficiently under the exam's local rules.
Submit the local contractor application and any required supervisor, master electrician, insurance or business documentation.
Open-book strategy: turn each question into a few useful code keywords, identify the likely NEC article or supporting reference, locate the rule quickly, check notes and exceptions, and then answer. Local exam timing varies, so practice with the exact time limit for your jurisdiction.

Missouri's optional statewide electrical contractor license is a broad credential. Local jurisdictions may separately regulate communications, alarms, low-voltage systems and related contractor work.
· Statewide electrical contractor license: optional state credential
· Local communications specialty licenses may still apply
· St. Louis County: 40-question Communication and Sound exam
· Kansas City: Class III low-voltage contractor path
· Jefferson County: Communications Contractor license
· Always verify the jurisdiction before scheduling an exam
Missouri Licensing Basics
St. Louis County Communication and Sound
Kansas City and Jefferson County Low-Voltage Paths
Missouri Statewide Electrical and Study Strategy
Build communications-circuit knowledge, alarm and sound-system confidence, CATV and broadband skills, NEC navigation speed, low-voltage code awareness and jurisdiction-specific exam readiness before you schedule.
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Missouri Communications Contractor Exam Prep