SkyDrill

Terminal lugs per stud

Aviation Mechanic Airframe (AMA) practice question 18 of 24 on Aircraft Electrical Systems. ACS element AM.II.K.K14 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic Airframe (AMA) practice mode.

Question bank updated 2026-09-22

QUESTIONWhat is the maximum number of terminal lugs that should be connected to any one terminal block stud?

  1. AFour, counting a common bus bar
  2. BFour, plus a common bus bar
  3. CSix, if the lugs are preinsulated
Show the answer and explanation

Correct answer: A. Four, counting a common bus bar

  • A — correct No more than four terminal lugs should be on one stud, and that total always includes a common bus bar joining adjacent studs.
  • B — incorrect Four terminal lugs plus a common bus bar are specifically not permitted on one stud.
  • C — incorrect Insulation type does not change the limit, and six exceeds the stated maximum.

BACKGROUND

Wire terminal lugs are used to connect wiring to terminal block studs or equipment terminal studs. No more than four terminal lugs, which includes three terminal lugs and a bus bar, should be connected to any one stud, and the total number per stud always includes a common bus bar joining adjacent studs. Four terminal lugs plus a common bus bar are not permitted on one stud. Terminal lugs should be selected with a stud hole diameter that matches the stud, and when stacked lugs vary in diameter the largest goes on the bottom and the smallest on top. Tightening the connection should not deform the lugs or the studs, and lugs should be positioned so that movement tightens rather than loosens the connection.

STUDY TIP

Read the limit as a total count of everything on the stud; the bus bar occupies one of the four places rather than sitting outside the count.

KEY POINTS

  • A stud carries no more than four terminal lugs in total.
  • A common bus bar counts toward that total of four.
  • Larger-diameter lugs go on the bottom of a stack, smaller on top.

SOURCES

  • sources/ama-airframe/ch09.txt "Terminal Lugs"
Practice the Aviation Mechanic Airframe (AMA) test →Timed 100-question exam, by ACS area, or review your misses. Free.
MORE ON AIRCRAFT ELECTRICAL SYSTEMS

SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-31B Aviation Maintenance Technician Handbook – Airframe, and 14 CFR part 43. Regulations and handbooks are revised; confirm details against the current edition.