The problem
Home chargers are mounted outdoors or in car parks, so their enclosure must keep out water and dust, survive impacts, shed heat, hold a heavy cable and be easy for an electrician to install. These needs pull against each other and against cost and appearance, making the enclosure a good complete product-design exercise.
Objectives
- Package an example charger board, contactor, RCD, terminal block and cable entry.
- Design a front cover and rear base with gasket groove, screws and a wall bracket.
- Design a cable holster and connector dock that hold the cable and connector securely.
- Check wall-mount strength, cover stiffness and internal temperature with simulation and hand calculations.
- Prepare drawings, an assembly sequence and renders for a design review.
What you need
Tools and toolboxes
- SOLIDWORKS Part and Assembly — Housing parts with Shell, Rib, Mounting Boss and Lip/Groove features, and an assembly with placeholder electronics.
- Draft Analysis — Check the moulded housing parts for draft before release.
- SOLIDWORKS Simulation (Static) — Wall bracket and screw loads with the cable weight and a person pulling on the cable.
- SOLIDWORKS Flow Simulation (optional) — Natural convection inside the sealed enclosure to estimate internal air and board temperatures.
- SOLIDWORKS Visualize or KeyShot — Renders of the charger on a wall for a design review.
Software
- SOLIDWORKS 2023 or later
- SOLIDWORKS Simulation
- SOLIDWORKS Flow Simulation (optional)
Extra parts and data
- Datasheets for the main components — Dimensions and heat dissipation of the contactor, RCD and power supply define the packaging and thermal load.
Key concepts
- IP code
- IS/IEC 60529 defines IP ratings: the first digit for solids and the second for water. Achieving a rating needs a sealing design and a test, not just a CAD model.
- Gasket compression
- A gasket seals when compressed within a range given by its supplier. The groove depth and screw spacing set that compression.
- IK impact rating
- A code from IEC 62262 for resistance to mechanical impact, often specified for outdoor chargers.
- Creepage and clearance
- Minimum distances between live parts and accessible conductive parts, set by electrical safety standards, which the enclosure must allow for.
Step-by-step guide
- 1
Write requirements
List requirements for an example single-phase 7.4 kW charger: outdoor wall mount, a target IP rating such as IP54 or IP65, an IK target, operating temperature range, a 5 m tethered cable with Type 2 connector, a status light bar and a mains entry from below. Note that charger safety and connectors are governed by standards such as IEC 61851 and IEC 62196, and ask the electronics designer for clearance distances.
Checkpoint: A requirement list with IP and IK targets, cable details and installation constraints.
- 2
Package the electronics
Model placeholder blocks from datasheets: main board, contactor, RCD or residual current device module, power supply, terminal block and cable glands. Arrange them on a mounting plate in an assembly so high-voltage parts are grouped, cable entry is at the bottom, and the installer can reach terminals with the front cover off. Leave space for clearance distances given by the electronics designer.
Checkpoint: A packaged layout fitting an envelope, for example 300 × 200 × 110 mm, with terminals reachable by a screwdriver body.
- 3
Sketch the form and split
Sketch two or three front concepts with the light bar, connector dock and logo area. Decide the split between base and cover so the parting line is easy to seal and water runs off; a rear base with a front cover overlapping it like a hood works well. Choose material, for example a UV-stable PC or PC/ABS grade, as an example.
Checkpoint: A chosen concept with a split line drawn and a reason for it based on sealing and water run-off.
- 4
Model the base and cover
Model the base with a uniform wall, for example 2.5 mm, using Shell, draft on side walls and internal Mounting Bosses for the plate. Model the cover with a matching Lip/Groove feature so a gasket sits in a groove around the base edge. Space cover screws closely enough for even gasket compression, following the gasket supplier's guidance. Add ribs inside the cover to stiffen the large front face.
Checkpoint: The base and cover mate with the gasket groove, and section views show gasket compression in the supplier's range at nominal.
- 5
Design the holster and dock
Design a connector dock on the front or side that holds the Type 2 connector at a natural angle, with a drip-proof shape so water does not collect in the socket. Design a cable hook or holster below for the coiled cable, and a strain relief where the cable leaves the base. Check the connector clears the wall and that a user can lift it out with one hand.
Checkpoint: Connector docking and removal path clear all geometry, shown with an assembly motion or a configuration at each position.
- 6
Design the wall bracket
Design a sheet metal or moulded wall bracket that the installer fixes first, so the charger hooks on and is secured by a screw. Position wall holes for standard anchors and use slots for levelling. Check the bracket hangs the charger so its centre of mass is close to the wall, which reduces anchor pull-out load. Add a provision for a security screw or padlock so the charger cannot simply be lifted off the bracket in a public car park.
Checkpoint: A bracket that lets the charger hang and lock, with anchor positions and levelling slots dimensioned.
- 7
Check strength
Run a static study on the bracket and base: gravity on the charger mass, an example 5 kg of cable on the holster and a 200 N pull on the cable at an angle to represent a user tugging, all as examples. Fix the anchor holes and use bolt connectors. Refine the mesh at hook and screw areas. Hand check anchor pull-out force with a moment balance.
Checkpoint: Factor of safety above a target such as 2 on the bracket and base, and the hand calculation of anchor force agrees with reaction forces.
- 8
Estimate internal temperature
Add up heat losses from datasheets, for example tens of watts at full current. Estimate internal temperature rise by hand using the enclosure surface area and a natural convection coefficient. If Flow Simulation is available, set up an internal analysis with heat sources on the components, natural convection outside and solar radiation on the front as a hot case. Compare with the hand estimate.
Checkpoint: Internal air temperature stays below the lowest component rating with margin in the hot case, or a heat path change is made.
- 9
Review sealing and assembly
Walk through the sealing path: cover gasket, cable glands, light bar window and connector dock. Mark every possible water path in a section view and say how each is sealed. Write an installer sequence: fix bracket, hang base, terminate cables, fit cover. Check every screw is reachable and the same size where possible. Note that the IP rating must be confirmed by a test to the standard.
Checkpoint: A sealing map with every opening addressed and a step-by-step install sequence.
- 10
Drawings, renders and report
Produce part drawings with draft notes and gasket groove details, an assembly drawing with BOM, and renders of the charger on a wall in SOLIDWORKS Visualize or KeyShot. Write a report with requirements, packaging, sealing design, strength and thermal checks and limitations, stating which results need physical tests, such as IP, IK and temperature rise. Add an exploded view showing the install sequence, which helps both the reviewer and an electrician understand the design.
Checkpoint: A drawing pack, renders and a report suitable for a design review.
Testing & validation
- Gasket compression at nominal is within the supplier range.
- Bracket and base factor of safety exceed the target, with hand check of anchor load.
- Internal temperature estimate by hand and simulation agree in trend.
- Every water path is identified and sealed in the design.
- IP and IK ratings are stated as test requirements, not as achieved values.
Expected results
A complete wall-box charger enclosure design with packaged electronics, sealed two-part housing, connector dock, cable holster and wall bracket, supported by strength and thermal checks, drawings and renders.
Take it further
- Design a three-phase 22 kW variant using configurations and compare thermal loads.
- Print the dock and test connector docking with a real connector.
- Run a drop test study on the cover if your licence includes it.
Viva and review questions
Does your CAD model prove IP65?
No. The design follows sealing principles and gasket compression ranges, but an IP rating is only confirmed by testing to IS/IEC 60529 on a physical sample.
Why put the cable entry at the bottom?
Water runs down, so a bottom entry with a gland is less likely to let water in, and it suits how mains cables usually come up from below or along the wall.
How did you size the wall anchors?
By taking moments about the bottom edge with the charger weight, cable weight and a pull load, to get the pull-out force on the top anchors, then checking it against a typical anchor rating with a safety margin.
Learn it at DIYguru
These DIYguru courses and programmes teach what this project needs.