Key takeaways
- Lock the deployment environment, the IP target and the heat load before the flat pattern. Most charger enclosure redesigns trace back to one of those three being decided late.
- IP65 is a system of gasket, seam geometry, door stiffness and cable entry — not a gasket you add at the end.
- Thermal strategy scales with power: louvers to roughly 22 kW, ducted forced air to 160 kW, liquid-cooling brackets above that.
- Galvanized steel is the default for commercial AC piles; 316 only where salt spray is genuinely present; aluminium where weight or passive dissipation matters.
- PEM hardware and modular sub-plates cut field assembly time more than any tolerance tightening does.
- A complete RFQ package gets a real quote in 24 hours. An incomplete one gets a guess, and the guess always lands low.
A European operator came to us with a 120 kW DC cabinet that had already been quoted twice. Both quotes were for the same drawing, and they differed by 41 percent. The reason was not margin: one supplier had assumed 1.5 mm galvanized with a single-door seal, the other had priced 2.0 mm with a double-labyrinth door and a welded, ground base. Neither was wrong. The drawing simply never said which environment the cabinet had to survive, so each estimator filled the gap with a different assumption. That is what an enclosure RFQ is really for — not to get a number, but to make every supplier price the same object.
This guide is written for procurement and engineering teams sourcing a custom EV charger enclosure from an OEM fabricator. It covers the decisions that actually move cost and lead time: material, ingress protection, thermal strategy, structural reinforcement, the DFM moves that save money without costing performance, and the twelve items a complete RFQ package should contain. For the fabrication process itself, see our sheet metal DFM guide.
Start With the Deployment Environment, Not the Drawing
A charging pile enclosure is a weatherproof, vandal-resistant, thermally managed container that happens to hold electrical equipment. Its requirements are set by where it stands, not by what is inside it. Before any metal is cut, four things should be written down:
- Site exposure: open kerbside, under canopy, coastal, industrial, highway rest area, underground car park.
- Worst-case ambient and solar load: a cabinet in a Gulf summer with direct sun on a dark finish sees a surface temperature 30 °C above ambient, and that number drives the entire cooling budget.
- Power class and duty cycle: 7 kW destination charging running intermittently and 160 kW highway charging at 90 percent duty are different machines.
- Service model: who opens the door, how often, and with what tooling. A cabinet that a technician opens weekly needs different hinges and hardware than one opened once a year.
Write these four into the RFQ. Every downstream decision — material grade, gasket type, vent area, wall thickness, hinge specification — becomes a deduction rather than a guess.
Material Selection for EV Charger Enclosures
Enclosure material selection balances structural strength, corrosion resistance, weight, thermal behaviour and landed cost. There is no universally best answer, only the best answer for a site class.
| Material | Strength | Corrosion | Weight | Cost index | Best fit |
|---|---|---|---|---|---|
| Hot-dip / electro-galvanized steel | High | Good inland, fair coastal | High | 1.0 (baseline) | Urban and highway AC and DC piles with a qualified powder system |
| Stainless 304 | High | Very good | High | 2.2 – 2.8 | Food-adjacent, chemical sites, premium retail forecourts |
| Stainless 316 | High | Excellent in salt | High | 3.0 – 3.8 | Coastal, ports, islands, de-icing salt exposure — see our coastal material comparison |
| Aluminium alloy (5052 / 6063) | Medium | Good with anodizing | Low | 1.8 – 2.4 | Wall-mounted units, portable chargers, applications where weight or passive heat spreading matters |
| Cold-rolled steel (SPCC) | High | Poor without coating | High | 0.8 | Indoor or fully sheltered enclosures where the finish carries the protection |
One caution that comes up repeatedly: do not mix metals inside a wet assembly without thinking about galvanic corrosion. A stainless door on an aluminium body, or bare copper busbar brackets against a galvanized panel, will corrode at the junction. Our material selection guide and galvanic corrosion guide cover the pairings in detail.
IP65 Sealing Is a System, Not a Gasket
An outdoor IP65 EV charger enclosure has to keep water and dust out for a decade of thermal cycling, UV exposure and door slamming. In our experience the failures are almost never the gasket material. They are the geometry around it.
- Sealing channel stiffness. A formed channel that deflects under the latch load opens a gap. The door panel and the cabinet flange both need enough section modulus to hold compression evenly around the whole perimeter — this is where stiffening ribs earn their keep.
- Compression set. Specify the gasket by compression range, not by profile photo. A 30 percent deflection target with a polyurethane or silicone extrusion survives cycling far better than a foam tape crushed flat.
- Overlapping seams and rain channels. An internal deflector above the door gap plus an overlapping door edge means water has to travel up and over before it reaches the seal.
- Cable entry. This is the number-one leak path we see in field returns. Gland plates, not individual glands through a thin wall, with a defined IP-rated entry component — see our IP65 gasket and sealing guide.
- Vent openings. Louvers must be rain-resistant by geometry, with an internal mesh and a drain path. A vent that passes an IP test in the lab but holds water in the field will fail within a season.
- Hardware. Concealed hinges, flush locks and tamper-resistant fasteners. Physical security on an unattended payment terminal is a specification item, not a nice-to-have — our IK rating guide sets the impact target.
Thermal Management by Power Class
Charging electronics derate with temperature, and a cabinet that runs hot shortens its own service life. The cooling strategy should be chosen from the power class and the worst-case ambient, and it should be decided before the internal layout is frozen — because it determines how much wall area is available for anything else.
| Power class | Typical internal heat | Cooling strategy | Enclosure implications |
|---|---|---|---|
| 7 – 22 kW AC | 150 – 600 W | Natural convection with rain-resistant louvers | High and low vents for a chimney effect; keep the vent path clear of the cable bay |
| 30 – 60 kW DC | 0.8 – 2 kW | Forced air with internal ducting | Fan wall, filtered intake, exhaust plenum on the opposite face |
| 120 – 160 kW DC | 3 – 6 kW | High-flow forced air, or air plus a liquid loop on the module cold plate | Dedicated module bay, bracketry for heat exchangers, pumps and hoses |
| 240 kW and above | 8 kW and up | Liquid cooling as primary | Liquid-cooling bracket integration, separate dry/wet compartments, leak management |
Whatever the strategy, the enclosure is part of the thermal solution. Surface finish matters more than most teams expect: a light-coloured, low-gloss powder coat on the sun-facing panels can cut solar gain substantially compared with a dark gloss. Our thermal management guide covers the calculations.
DFM Moves That Cut Cost Without Cutting Performance
Early DFM review is the cheapest engineering hour you will buy on a charging pile programme. These are the five changes that most often come out of ours:
- Thinner sheet with ribs instead of thicker sheet. 1.5 mm with two formed stiffening ribs is stiffer, lighter and cheaper than 2.0 mm flat, and it improves natural convection at the same time.
- Bend sequence rationalisation. Reducing the number of part orientations on the press brake is worth more than shaving tolerances. Four extra flips per part is four extra handlings per part.
- Self-clinching hardware instead of weld nuts. PEM nuts, studs and standoffs remove a welding operation, a grinding operation and a distortion risk in one move. See our fastener selection guide.
- Modular sub-plates. A removable module tray or mounting plate lets electrical assembly happen away from the cabinet and makes field service a part swap.
- Prototype before tooling. A laser-cut and bent prototype validates the door seal, the cable bending radius and the fit of every internal bracket — the three things drawings never reveal.
What to Put in the RFQ Package
Twelve items. Missing any one of them means the supplier has to assume, and assumptions are where 40 percent quote spreads come from.
- 2D drawings with full dimensioning and critical tolerances called out.
- 3D CAD in STEP or IGES, not just a rendered PDF.
- Material grade, sheet thickness per panel, and acceptable substitutes.
- Target IP rating and the test standard it will be verified against.
- Surface specification: pretreatment, coating type, thickness, RAL or Pantone, gloss level.
- Salt spray expectation, in hours, with the standard (ISO 9227 or ASTM B117).
- Internal heat load, in watts, and the worst-case ambient and solar condition.
- Vent area, fan positions, filter class, and any liquid-cooling components.
- Cable entry sizes, quantities, and the gland hardware to be used.
- Mounting interface: base fixing pattern, pedestal or wall, seismic or wind load if applicable.
- Annual volume and expected batch sizes, plus the target first-article date.
- Certification or documentation requirements — UL, CE, IEC 61439, plus any PPAP-style inspection reports.
AC Versus DC Fast Charger Enclosure: What Actually Changes
| Item | AC charging pile | DC fast charger cabinet |
|---|---|---|
| Envelope | Compact wall or pedestal housing, 400 – 800 mm | Floor cabinet, often 1700 – 2000 mm tall |
| Weight and base | Light; wall fixings or a small footing | Heavy cable load; reinforced base and lifting provisions |
| Internal architecture | Single compartment, simple backplate | Separate power bay, control bay and cable bay |
| Thermal | Natural convection | Ducted forced air, or liquid for high power |
| Service access | Front door, module swap | Front and rear access, removable module trays |
| Typical cost driver | Finish and appearance | Welding volume and internal bracketry |
For coastal and roadside sites, specify the corrosivity category rather than a bare hour count, and read what a salt spray hour requirement can and cannot prove before you write the number into the enquiry.
How SanJun Runs an EV Charger Enclosure Programme
- Requirements review. Site class, power, thermal load and service model turned into a written enclosure specification.
- DFM and drawing support. Concepts or size requirements turned into production drawings, with free design support on the enclosure structure.
- Prototype. Laser cutting, CNC bending, welding, grinding, riveting and finishing in-house, typically two to four weeks from released drawings.
- Validation. Fit check with the real electrical assembly, seal check, and coating verification.
- Production. Repeatable batches with dimensional inspection, coating checks and pre-assembly verification.
We fabricate AC charging pile enclosures, DC fast charger cabinets and supporting sheet metal parts — internal mounting plates, module sub-chassis, busbar brackets and cable management — as one package, so the mechanical interfaces are our problem rather than yours.