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OH Elevator Mechanic study materials
OH Elevator Mechanic study resources

OH Elevator Mechanic: Mechanical and Electrical Installation

OH Elevator Mechanic · Work through your exam, one topic at a time.

All guide sections

Mechanical and Electrical Installation

What this domain tests

Mechanical and electrical installation covers the hardware that makes the unit run: machines, sheaves, ropes, guides, buffers, hydraulic power units, controllers, feeders, disconnects, grounding, and travel cables. Questions often combine A17.1 installation rules with NEC Article 620 and basic motor-circuit math.

Core rules

  • The elevator main line disconnect must be lockable, located in the machine room, readily accessible, and within sight of the controller. It must not be shared with unrelated loads.
  • Motor branch-circuit conductors are generally sized at 125% of nameplate full-load amps. The disconnect ampere rating must be at least 115% of nameplate FLA. Overload protection is based on the motor nameplate and service factor, not on the next larger breaker.
  • Ropes must be matched and tensioned. Uneven rope tension causes sheave wear and false safeties.
  • Hydraulic units require the correct relief-valve setting, tank breathing, oil level, and piping that does not create trapped pressure.
  • Machine-room and pit electrical equipment must be protected from moisture and mechanical damage. Pit receptacles and lighting are required by A17.1.
  • Grounding and bonding must be continuous. The elevator feeder equipment grounding conductor is not a current-carrying neutral.

Worked example

A 208-V, three-phase elevator motor has a nameplate FLA of 42 A. Conductor sizing: 42 × 1.25 = 52.5 A, so a 60-A conductor ampacity is the minimum practical selection. Disconnect sizing: 42 × 1.15 = 48.3 A, so a 60-A disconnect is acceptable. Overload protection is not set at 60 A; it is selected from the nameplate FLA and service factor. The reasoning separates conductor ampacity, disconnect rating, and overload protection-three different calculations that candidates often collapse into one.

Traps

Using 125% for every calculation; sizing overloads from the breaker; omitting the lockable disconnect; landing the elevator feeder on a shared panel; and ignoring rope equalization after a rope change.