LiftMaster K10-33850 E-Box Cover for MH, MJ and MT Commercial Operators
The LiftMaster K10-33850 is the replacement cover for the electrical box on select LiftMaster medium-duty commercial door operators. The electrical box cover gives the control compartment a finished, serviceable closure and helps keep the operator controls protected from normal shop, warehouse, and commercial door environments.
This part is often needed when the original e-box cover is bent, missing, cracked, corroded, or damaged during service. A missing cover can expose wiring, terminal blocks, switches, and control components to dust, impact, or accidental contact. Replacing the cover is a simple parts need, but it still matters for safety and proper operator protection.
K10-33850 is not the same as a complete NEMA enclosure. It is also not a logic board, wire harness, transformer, or control station. The most reliable fitment method is to match the operator model and the electrical-box breakdown. MH, MJ, and MT are the primary references in the product name, while some parts references also associate the cover with related medium-duty families such as BMT, MHS, and MGJ when the same electrical-box style is used.
Where This Part Is Commonly Used
Use this cover when the control box is otherwise intact and only the access cover or door needs replacement. If the enclosure itself is broken or rusted, a complete enclosure or model-specific electrical box kit may be required instead.
If a missing cover allowed water, dust, or pests into the control box, inspect the board, terminal strip, harnesses, and safety-device wiring before returning the operator to service.
Compatible With
K10-33850 should be used where the commercial operator parts diagram lists this electrical-box cover. Compatible and commonly associated applications include:
- LiftMaster MH medium-duty hoist commercial door operators where K10-33850 is listed
- LiftMaster MJ medium-duty jackshaft commercial door operators where K10-33850 is listed
- LiftMaster MT medium-duty trolley commercial door operators where K10-33850 is listed
- Related LiftMaster medium-duty operator electrical boxes, including select BMT, MHS, and MGJ references where the same cover is called out
- Not a complete enclosure and not a replacement for NEMA 4 enclosure kits
Features and Specifications
| Feature / Specification | Details |
|---|
| Manufacturer | LiftMaster |
| Product Type | Electrical box cover |
| Part Number | K10-33850 |
| Application | Medium-duty commercial door operator e-box cover |
| Compatible Operator Type | Select MH, MJ, MT and related medium-duty electrical boxes |
| Voltage | Not voltage-specific by itself |
| Included Components | Cover only unless supplier packaging states otherwise |
| Notes | Match to the operator parts breakdown before ordering |
Also Known As / Related Part Numbers
This cover may be searched under several names:
- K10-33850
- 10-33850
- LIF-K10-33850
- E-box cover
- Electrical box cover
- Control panel door
- Control box cover
- MH MJ MT e-box cover
Technician Note
If the old cover is missing, inspect the inside of the electrical box before simply installing a new one. Loose wiring, insect nests, water staining, overheated terminals, or corrosion can create larger service problems than the missing cover itself.
Before Ordering
- Confirm your operator is an MH, MJ, MT, or related medium-duty model that lists K10-33850.
- Confirm you need the cover only, not the complete enclosure or full electrical box kit.
- Check whether mounting screws, hinges, or gasket parts are included or reused.
- Inspect the box for corrosion, damaged wiring, or missing labels before reassembly.
- Do not leave the operator running with exposed electrical controls.
Professional Advisory
The cover itself is a mechanical part, but it protects an electrical compartment. Disconnect power before opening or servicing the operator and have damaged wiring or controls inspected by a qualified commercial door technician.
Product Questions and Answers
Is K10-33850 a complete electrical box?
No. K10-33850 is an e-box cover or control panel door. It is not the full enclosure or a complete electrical box assembly.
Which operator models commonly use this cover?
It is primarily associated with LiftMaster MH, MJ, and MT medium-duty commercial operators, with some related medium-duty electrical-box references depending on the parts diagram.
Does this cover include the logic board?
No. The logic board, wire harness, terminal block, and other internal controls are separate parts.
Can I use this on a NEMA 4 outdoor enclosure?
Do not assume that. K10-33850 is not the same as a NEMA 4 complete enclosure. Match the cover to the operator parts diagram.
Why replace a missing electrical-box cover?
The cover helps protect wiring and control components from dust, impact, and accidental contact. A missing cover can also allow moisture or debris into the operator.
