LiftMaster K74-39299-2 E-Box for SL595103UL and SL595203UL
The LiftMaster K74-39299-2 E-box is the electrical control box assembly used on SL595103UL and SL595203UL heavy-duty industrial slide gate operator applications. In these heavy commercial and industrial slide gate operators, the E-box organizes the power/control components and helps keep the operator wiring protected from dirt, moisture, vibration, and accidental contact. A damaged E-box can lead to unreliable operation, unsafe wiring conditions, failed components, or code-compliance concerns in high-use vehicular gate systems.
This is a configuration-specific service part. The model suffix on the operator matters because SL585 and SL595 operators were built in different horsepower, voltage, and phase versions. Before ordering, compare the installed operator model number, power supply, phase, horsepower, and the original E-box part number. Do not substitute another K74-39295 or K74-39299 assembly just because the cabinet shape appears similar.
Compatible With
Use with the following LiftMaster applications when the operator parts diagram calls for K74-39299-2.
- LiftMaster SL595103UL
- LiftMaster SL595203UL
- Select 1HP and 2HP 3-phase AC dual-voltage SL595UL commercial slide gate operators where listed
- K74-39299-2MC applications where confirmed by parts diagram
Features and Specifications
| Specification | Details |
|---|
| Manufacturer | LiftMaster |
| Product Type | E-box / electrical box replacement assembly |
| Part Number | K74-39299-2 |
| Application | SL595UL heavy-duty industrial slide gate operator E-box service applications |
| Compatible Operator Type | Industrial AC slide gate operator |
| Horsepower / Phase | 1HP and 2HP, 3-phase AC references in supplier listings |
| Voltage / Power Notes | 3-phase AC dual voltage 208-240V/480VAC references; verify operator nameplate |
| Safety Monitoring | Designed for UL325-era commercial gate operator control systems when matched to the proper model |
| Included Components | Electrical box assembly; confirm current kit listing for exact included parts |
| Notes | Match model suffix, voltage, phase, and parts diagram before ordering |
Also Known As / Related Part Numbers
- K74-39299-2
- K74-39299-2MC
- LM-K74-39299-2
- 74-39299-2
- K74-39299-2MC
- 74-39299-2
- Electrical box assembly SL595103UL SL595203UL
Technician Note
E-box replacement on industrial slide gate operators is not a cosmetic repair. Confirm the incoming power, motor wiring, control wiring, surge protection, loop detector wiring, monitored entrapment protection, and grounding before returning the gate to service.
Before Ordering
- Match the complete operator model number from the nameplate
- Confirm horsepower, voltage, and phase before ordering
- Compare the original E-box part number against the parts diagram
- Inspect contactors, board connections, wiring, conduit entries, and cabinet seals
- Use a qualified gate technician for electrical transfer and safety testing
Professional Advisory
Control box and E-box replacement involves operator power, batteries, wiring, and safety-device connections. Installation and electrical troubleshooting should be performed by a qualified gate technician, especially on commercial operators, high-voltage systems, or any gate that moves unexpectedly. Do not bypass monitored entrapment protection or required safety devices.
Important Ordering Warnings
- Do not substitute a different K74 E-box when voltage or phase is different
- Do not use a single-phase E-box on a three-phase operator or a 575V E-box on a dual-voltage operator
- Do not operate the gate until monitored safety devices and gate travel are verified after service
Product Questions and Answers
What models is K74-39299-2 used with?
K74-39299-2 is used with LiftMaster SL595103UL and SL595203UL heavy-duty industrial slide gate operators when the operator parts diagram lists this E-box assembly.
Why do voltage and phase matter on an E-box?
The electrical controls and power components are matched to the operator power package. A wrong-voltage or wrong-phase E-box can create unsafe operation or component failure.
Is this E-box interchangeable with other SL585 or SL595 E-box assemblies?
No. Similar K74 E-box part numbers may fit different horsepower, voltage, or phase configurations and should not be substituted without a parts diagram match.
Does replacing the E-box require a gate technician?
Yes. These assemblies involve commercial gate electrical wiring, safety-device wiring, and high-voltage service that should be handled by a qualified technician.
What should be checked after installation?
Check power, grounding, board wiring, limit operation, brake or motor control where applicable, accessories, loops, monitored photo eyes or edges, and complete gate operation.
