A Guide To EV Charger Pedestal Design

When access to a suitable wall is not an option, pedestals are a simple solution for EV charger mounting. We have spent considerable time designing pedestals to complement our product offering. Whether you are seeking more background information before buying our pedestals or looking to manufacture your own, we think this information will help.

Henry Harvey Evnex
Henry Harvey | Industrial Designer
Pedestal mounted EV charging stations in a car park
Pedestal mounted charging stations can provide a cost effective option for public and commercial EV charging.

Common Pedestal Materials

Mild or Low Carbon steel is a common choice for outdoor infrastructure. It is cheap, strong, readily available and easy to work with. It is very susceptible to rust and therefore needs to be protected. For EV charger applications, we would recommend a minimum protection of hot dip galvanising. Some of our earlier pedestals were hot dip galvanised and we are confident they will offer long term protection even in coastal areas of New Zealand. Duplex coatings offer further protection, many colour options and are somewhat of an industry standard for mild steel subject to the outdoor elements for very long periods of time. A common duplex coating is hot dip galvanising followed by powder coating. The main downsides apparent to us is the aesthetic variability of the hot dip galvanising showing through the powder coat & the clean-up required in between the hot dip galvanising stage and the powder coating stage. We would not recommend simply powder coating mild steel as we do not believe it will offer long term protection.

Stainless steel is another common material used outdoors – generally for infrastructure that requires a higher level of finish than galvanised mild steel. Common grades are 304 and 316. 304 is a less expensive grade that is less resistant to rust and ‘tea-staining’ than 316. Both grades benefit hugely from electropolishing – we see it as a requirement to prepare welded stainless products for a life outdoors. In simple terms, electropolishing will remove impurities and surface roughness from your stainless parts, increasing their resistance to corrosion and improving their visual appeal. To properly prepare welded parts for electropolishing, we recommend cleaning up the TIG welds first via suitable mechanical means such as manual or power tool abrasion. Be careful that this does not cause deep scratches or marks as the electropolish process will not remove these. Evnex only uses 316 in our current pedestal offerings as we believe the small added material cost of 316 over 304 is offset by the superior lifespan in the largely coastal New Zealand outdoors.

Aluminium is often used outdoors and is usually powder coated. It is possible to use aluminium outdoors without applying a surface coating, but it is not recommended. Depending on the installation site, rainfall, proximity to the coast, air pollution and humidity, bare aluminium can oxidise badly. Our aluminium pedestals are chemically cleaned and then powder coated to ensure a good lifespan outdoors and plenty of colour options. Be aware that some colours of powder coating are much more UV stable than others. A UV stable red, for example, may cost significantly more that a UV stable black. Aluminium RHS of the type we use is not always immediately available depending on your location.

Design

Standard - 316 Stainless Steel

This design utilises relatively inexpensive “Dairy Tube” in a form factor that can either be finished as a single or dual style assembly. The main pole is designed so that the input cable can routed up through the centre which requires pre-planning during the pouring of concrete or asphalt to ensure that there is provision for a concealed input. If this is not practical then there are M32 compatible drill-out holes on either side of the base. These are designed so that a 4mm drill bit can be used to remove the tabs. The input cable exits the tube via the 32mm wide slots. The tubes are cut with only one slot fully cut out. For dual assemblies, the second slot can be punched out via the other slot with a large punch. Rubber sheet metal edging adds a nice touch here to protect the cables from metal edges.

An Evnex charging station mounted to a stainless steel pedestal
Our Standard stainless pedestal with Evnex R22 charge point.

The mounting plates for the charge point enclosures are constructed from laser cut 2mm steel, which is folded at either end. Tabs locate the top of these plates in the tube for ease of assembly before welding. We install M4 316SS rivnuts in these plates to create mounting points for the charge point enclosure. This should be done after electropolishing to ensure that electropolishing fluids do not become trapped in these details, as the fluid can leak out and severely mark your shiny new product.

Branded - Rectangular Hollow Section Aluminium

While functionally similar to our Standard pedestal, the aluminium pedestal gives a more premium look and allows for greater branding opportunities due to the large uninterrupted surfaces. It is well suited to large decals, vinyl wraps and signage such as instruction panels. The machining process forms the installer access area, mount holes and the beginnings of the rounded top corners. Dual style pedestals can be created by machining mount holes and an M32 hole on the opposite side. However you can also just mark these holes internally during the machining process by drilling to the correct depth. This allows single pedestals to be easily turned into dual pedestals at a later stage with an appropriately sized drill bit and an M32 holesaw for the input hole. We recommend drilling holes before powder coating.

An Evnex charging station mounted to an aluminium pedestal
An early version of our Branded aluminium pedestal with Evnex R7 charge point - courtesy of Electra Networks.

The trickiest part of the aluminium pedestal fabrication is welding on the rolled top cap and then blending the welds to create a uniform finish. Even a relatively thick powder coat will show up marks if the welds have not been ground and blended well.

"While functionally similar to our Standard pedestal, the aluminium pedestal gives a more premium look and allows for greater branding opportunities due to the large uninterrupted surfaces."

Fabrication

Branded Pedestal Fabrication - Aluminium

Our aluminium pedestals require machining, laser cutting, sheet metal bending, welding, grinding & powder coating. They are relatively straightforward to make but benefit from fabrication shops that specialize in aluminium welding as they are likely to own MIG aluminium welding gear which is a faster process than TIG aluminium welding and can offer welding finishes almost as good as TIG in the right hands.

Standard Pedestal Fabrication - Stainless Steel

These pedestals require laser cutting (flat & rotary), sheet metal bending, welding and electropolishing. We recommend TIG welding this design as it has quite thin walls and welds that are very visible to the user. The parts require sharp edges to be removed and extra care should be taken around areas where cables might rest or be pulled through.

Isolators

Some installers insist on using isolators in the final circuit at the location of the charging station, as well as the necessary MCB (Miniature Circuit Breaker) and RCD (Residual-current Device) at the distribution box. The requirements within New Zealand at the time of writing are somewhat open to interpretation. Evnex suggests that an isolator is not required as it adds extra expense, detracts from the visual appearance, and creates problems when users unnecessarily turn off the charge point. This can potentially lock their cable plug in the socket. However, the decision rests with whoever is signing off the installation and for that reason we can provide isolator plates for the Standard pedestal. These are laser cut plates with rivnuts for mounting the isolator. These isolator plates key into the mount plates and are riveted onto the pole. We use commonly found PDL single gang isolators. Isolators can be installed on the Branded pedestal but this is left for the installer to arrange.

Earthing

As there is generally a requirement to ‘earth’ pedestals, we have designed an earth stud which is installed during the mounting of the charge point. This allows for an earthing ring terminal to easily be attached, creating a solid, watertight electrical path through the plastic enclosure into the pedestal. There is a brass version suitable for the Standard (stainless) pedestal and an aluminium version suitable for the Branded (aluminium) pedestal. Material choice is largely dictated by conductivity and potential for galvanic corrosion.

Design Files

Our pedestals are designed and manufactured in New Zealand for the southern hemisphere market. We're conscious of the carbon impacts of shipping these products across the world, so we've decided to provide our design files free of charge for customers to build their own. Check out our pedestal design files here.

Henry Harvey Evnex
Henry Harvey | Industrial Designer