What Is Electronics Chassis Secret Storage? (False PSU Boxes)
Electronics chassis secret storage usually means a storage box made to resemble a computer power supply, or PSU. That disguise can block cooling, confuse service work, and create electrical-code problems. A safer choice is a clearly identifiable, lockable cabinet near the equipment, installed without covering vents, cables, controls, or required electrical working space.
Powder-coated steel is a useful material to consider because it is common in equipment cabinets and can take a durable finish. But a convincing finish does not make a storage box safe to place around live equipment. The key distinction is simple: store items in a separate, labeled enclosure, rather than making the enclosure look like a working PSU or altering one.
When I assess a proposed installation, I start with the equipment’s manual and the local code, not the size of a decorative shell. A computer PSU’s airflow needs vary by model. There is no universal clearance or airflow figure that makes a false PSU box safe.
Plan a Code-Compliant, Non-Disguised Enclosure
A lockable storage cabinet can provide controlled access without pretending to be electrical equipment. Plan it as a separate fixture: identify what it will hold, where it will mount, and how people will reach the equipment around it. Do not build a false PSU housing or modify a listed electrical product.
“Listed” or “labeled” means a product has been evaluated and marked for particular uses. NEC 110.3(B) requires listed or labeled equipment to be installed and used according to its instructions, where that rule applies under the locally adopted code. A decorative cover that conflicts with those instructions is not a workaround.
Start with an equipment survey. Record the equipment make and model, locate the installation manual, and note its intake and exhaust openings, cable routes, controls, and service access. Also check whether an electrical panel or other equipment governed by electrical working-space rules is nearby.
Choose a separate enclosure. A cabinet should be plainly identifiable as storage, with a secure door or lid that does not hide switches, labels, vents, or service panels. Keep it far enough from the equipment to preserve the clearances stated by the manufacturer. Do not infer those clearances from the equipment’s outside dimensions.
Take measurements at the site. Measure the intended cabinet footprint, door swing, wall framing, nearby cables, and access route. Make a simple plan showing the equipment and cabinet outlines. This catches conflicts before drilling or fastening.
| Planning item | What to check | What not to assume |
|---|---|---|
| Equipment model | Manual, listed use, and ventilation openings | That all PSUs need the same clearance |
| Cabinet location | Door swing, cable paths, and service access | That a small box cannot obstruct work |
| Mounting surface | Framing or a suitable rated surface | That drywall alone will carry any load |
| Nearby electrical gear | Whether a required work area applies | That every computer setup has NEC panel clearances |
Key takeaway: Keep storage separate and recognizable. The equipment manual and the locally adopted code govern the layout.
Check Equipment Ventilation and Electrical Clearances
Ventilation is the path air uses to enter and leave a device. A cover or nearby cabinet can restrict that path even when it does not touch the device. Check the product’s installation instructions for required spacing, orientation, and access; do not guess at airflow or use a generic clearance number.
A PSU’s fan direction and cooling design depend on the model. A decorative shell can obstruct an intake or exhaust, raise operating temperatures, or conflict with the product’s listing. There is no universal safe airflow rate or “false PSU” dimension. If the manual does not make the installation clear, ask the manufacturer or a qualified technician before adding anything nearby.
Know when electrical working-space rules apply. NEC 110.26 applies to qualifying electrical equipment, not automatically to a computer PSU or storage box. For equipment operating at 600 volts or less where the section applies, 110.26(A)(1) sets working-space depth at 3 to 4 feet, depending on the installation conditions in the adopted code.
Under 110.26(A)(2), working-space width must be at least 30 inches or the equipment’s width, whichever is greater. The space need not be centered on the equipment. Under 110.26(A)(3), working-space height is generally 6.5 feet or the equipment’s height, whichever is greater. Qualifying doors or hinged panels must open at least 90 degrees under 110.26(A)(2).
These are electrical-workspace requirements, not general spacing rules for a computer or storage cabinet. Confirm the adopted NEC edition, local amendments, and whether the specific equipment falls within the rule. Do not place a cabinet in a required workspace or block access to a panel.
Check the whole service path. A device may need room for a technician to remove a cover, reach a plug, or replace a cable. A cabinet that leaves the vents open can still make service difficult. Keep doors, removable panels, and cable connections accessible as the manufacturer directs.
Key takeaway: Follow the exact equipment instructions, and apply electrical clearances only where the code requires them.
Install and Secure the Storage Cabinet
A secure installation depends on the cabinet, its contents, the wall or floor, and the fasteners working together. Select a cabinet made for the intended use, then mount it to framing or another suitable rated surface. Do not rely on an unverified load rating or assume that a single fastener type fits every wall.
1. Confirm the location. Compare the site measurements with the cabinet’s outside dimensions, open-door swing, and the equipment’s stated clearances. Recheck electrical working space if a panel is nearby. If the cabinet would cover a vent, label, service opening, or required access area, choose another location.
2. Identify the substrate. A substrate is the material receiving the fasteners, such as wood framing, masonry, or a rated mounting surface. Locate and verify the support before drilling. Choose hardware suitable for that material and the expected load. If you cannot confirm the support or load capacity, pause and consult a qualified installer.
3. Mount the cabinet as designed. Follow the cabinet maker’s instructions. Keep it level and secure, and avoid cutting or drilling into the equipment, its enclosure, or nearby wiring. Do not attach storage to a PSU or electrical enclosure unless the manufacturer expressly permits that use.
4. Load and inspect. Keep the stored load within the cabinet’s stated limits, if provided. Close and open the cabinet door, then check that it does not strike equipment or cables. Make sure the cabinet remains separate from equipment vents and removable covers.
| Example layout | Suitable next step | Stop and reassess if… |
|---|---|---|
| Cabinet beside a desktop tower | Check the PSU manual, vents, cable access, and door swing | The cabinet blocks an intake or exhaust |
| Cabinet near a breaker panel | Measure the required workspace under the adopted code | Any part of the cabinet enters that workspace |
| Cabinet mounted on a framed wall | Verify framing and select compatible hardware | Support or load capacity is uncertain |
| Cabinet near a service panel on equipment | Keep the panel reachable and operable | The cabinet hides labels or blocks removal |
Key takeaway: Mount the storage cabinet to a suitable structure, not to operating electrical equipment.
Verify Access, Airflow, and Local-Code Compliance
A final inspection checks the installation as people will use it. Confirm that the cabinet is visibly storage, that equipment remains ventilated, and that service routes stay clear. Then compare the finished layout with the equipment instructions and local requirements. A tidy appearance is not proof of compliance.
Use this short check before loading the cabinet:
- The equipment model and its installation instructions are known.
- Intake and exhaust openings are unobstructed.
- Cables, labels, controls, and service covers remain accessible.
- Any required electrical working space is clear.
- The cabinet is secured to a suitable mounting surface with appropriate hardware.
- The cabinet door opens without striking equipment or blocking a route.
- No listed electrical equipment has been altered or covered against its instructions.
- Local permit or inspection requirements have been checked where applicable.
If the installation is near a panel, have a qualified electrician review uncertain code questions. If equipment temperature, airflow, or clearance is unclear, ask the manufacturer or a qualified technician rather than testing a homemade cover in service.
Installation examples
These are illustrative scenarios, not claims about specific completed jobs. They show how the same planning rules lead to different decisions.
Example 1: Storage beside a desktop computer. A homeowner wants a small lockbox near a tower. The installer checks the tower manual and finds the PSU intake and exhaust locations. The proposed cabinet would sit in front of one opening, so the location is rejected. Moving the cabinet to an adjacent clear section of wall preserves the airflow path and keeps storage separate.
Example 2: Storage near a breaker panel. A tradesperson proposes a lockable cabinet on the same wall as a panel. The installer checks the panel’s applicable working space under the locally adopted code before marking holes. If the cabinet would enter that space, it must move; the panel’s required access is not a storage zone.
Example 3: A cabinet on an uncertain wall. A DIY builder finds that the intended spot has no confirmed framing and is not sure what load the cabinet and contents will place on it. Rather than choosing fasteners by appearance, the builder verifies the support or selects a suitable rated mounting surface. If the wall cannot be verified, the installation pauses.
Key takeaway: Verify the finished space, not just the cabinet itself. When a clearance or mounting detail is unknown, stop and get the right technical review.
FAQ: False PSU Boxes and Electronics Storage
These answers distinguish a disguised storage box from a separate, code-conscious cabinet. The short rule is to preserve equipment cooling, service access, and any required electrical workspace. If a manufacturer’s instructions or local code are unclear, get qualified advice before installing the enclosure.
What is a false PSU box?
It is a storage container designed to resemble a computer power supply unit. It is not a standard electrical enclosure, and disguising it can confuse service work or obstruct equipment.
Is it safe to put a box around a computer PSU?
Not by default. The PSU’s airflow and clearance needs vary by model. Follow its manual and do not block openings or enclose it contrary to its instructions.
Is there a standard false PSU box size?
No. There is no universal size, clearance, or airflow rate for a safe enclosure. The actual equipment manual controls.
Can I mount a storage cabinet beside a PSU?
Possibly, if it is separate, securely mounted, and does not block vents, cables, controls, or service access. Check the equipment instructions before choosing the location.
Does NEC 110.26 apply to a computer power supply?
Not automatically. It covers qualifying electrical equipment where the section applies. Confirm the equipment type, adopted code edition, and local amendments.
What are the NEC 110.26 working-space dimensions?
For qualifying equipment at 600 volts or less, depth is 3 to 4 feet depending on conditions. Width is at least 30 inches or equipment width, whichever is greater; height is generally 6.5 feet or equipment height, whichever is greater.
Can a cabinet go in front of an electrical panel?
Do not place it in required electrical working space or where it blocks access. Have a qualified electrician assess uncertain layouts under the locally adopted code.
Can I modify a listed PSU to add storage?
No. Do not alter or cover listed equipment contrary to its listing or instructions. NEC 110.3(B) requires covered equipment to be installed and used according to those instructions.
How should I secure a wall-mounted cabinet?
Verify the wall support, cabinet instructions, and expected load, then select hardware suitable for that substrate. Do not assume drywall or an unverified fastener can carry the load.
What should I do if the manual gives no clear airflow guidance?
Do not guess or add a decorative shell. Contact the manufacturer or a qualified technician and keep the vents and service areas unobstructed until the installation is confirmed.
(This article was written by one of our staff writers, Garrett Vance. Visit our Meet the Team page.)
