Customizing electrical enclosures
When designing control systems for machines, standard or custom electrical enclosures are needed to house automation hardware. The development of these electrical enclosures grew with the use of electricity in the early 20th century. Today’s electrical enclosures support the commercial and industrial markets by protecting a wide variety of automation hardware and wiring from ambient environments.
There are thousands of part numbers for different types and sizes of electrical enclosures made from a variety of materials including carbon steel, galvanized steel, stainless steel, and non-metallic materials, such as fiberglass or polycarbonate.
Selecting electrical enclosure features based on the required size and environmental conditions is the starting point of the design. The design phase includes panel layout, enclosure layout, and thermal considerations to determine how the enclosure must be customized to meet requirements. The main customization step usually is making cutouts in the enclosure, a procedure that can be performed in-house or by the manufacturer (see Figure 1).
Customizing the electrical enclosure
In some cases, it can be advantageous to have the manufacturer provide an enclosure with customized cutouts. The types of enclosure cutouts include:
- Human-machine interface (HMI)
- Gauges and meters
- Pushbuttons, switches, and lights
- Potentiometers and thumbwheels
- DIN controllers.
Cutouts made by the manufacturer reduce end-user labor costs and can improve quality. If the same type of enclosure and cutouts are repeatedly required, as is the case for many OEM machine builders, the manufacturer often can provide a part number to simplify ordering.
Cutouts often take significant time to layout, drill, and cut. In many cases, there is little room for error. Crooked or oversized cutouts present a poor appearance and compromise the enclosure rating. Touch-up paint may be required after cutouts are made, further adding time and expense.
When a manufacturer makes cutouts, they can use their manufacturing and fabrication facility’s resources to ensure all work is done correctly and precisely, and without compromising the enclosure.
Precautions for electrical enclosure cutouts
Do-it-yourself (DIY) cutouts can be made in the electrical enclosure after delivery, but this requires several steps. Each cutout needs to be carefully measured and marked (see Figure 2), with care to avoid any scratches, which may require taping. With the cutout’s shapes properly aligned, spaced, and marked-drilling and cutting can begin.
Significant time is required to layout and cut the holes. Power tools and special supplies are required. While polycarbonate or fiberglass can be easy to cut, carbon steel and stainless steel enclosures quickly consume cutting blades, and special tools are needed to make large holes.
Once the holes are cut, they must be smoothly filed to remove burrs and rough or sharp edges. Cleanup of cutting debris, oil and tape and removal of cutout markings also is required. After cleanup, the bare steel edges, exposed by cutting, must be painted to inhibit corrosion. At this point, the actual panel build and assembly can begin.
Despite the care required when making DIY cutouts, this can be the best option if just a few simple cutouts are needed, particularly for polycarbonate or fiberglass enclosures. Another scenario where DIY cutouts are the best option is when the OEM or end-user has significant machine shop resources on-hand for cutting, grinding, and painting.
Quicker cutouts for electrical enclosures
To get to the build and assembly stage faster, purchasing a customized enclosure directly from a manufacturer is another option. This does not eliminate the design phase, and cutouts still may need to be added. But it does significantly simplify the build phase, especially if multiple, duplicate enclosures are produced. The result is a customized enclosure, with accurate cutouts to exact specifications.
Many enclosure manufacturers offer customized enclosures with factory cutouts per each end user’s or OEM’s specifications. Some of these manufacturers also offer an online graphical configuration utility that can be used to select several cutout types and sizes, which the user can place in one of several standard enclosures.
Once the electrical enclosure is designed and the drawings are approved, the next steps that take place are the:
- Customized enclosures are typically cut and fabricated by automated equipment including laser cutting, bending and welding machines
- Enclosures are then painted, and baked in an oven if required
- Electronic drawings also are typically included, such as a 3-D model of the enclosure and a 2-D drawing with dimensions.
Customized enclosures are built to order and cannot be returned unless they are damaged during shipping. This highlights the need to carefully design the enclosure cutouts. Careful attention to the cutout’s dimensions or using standard cutouts provided by the enclosure manufacturer helps guarantee the customized enclosure meets the design requirements.
Figure 3 depicts a customized enclosure design that was created using an online graphical configuration utility provided by a manufacturer. Using standard cutouts and enclosure sizes works for many applications and helps ensure an accurate design that is simple to create. After the design is created, reviewing and approving the customized enclosure drawings is the final step to purchase the customized enclosure.
Many steps are required to specify and customize an electrical enclosure. For some end-users and OEMs, it may be advantageous to have the enclosure manufacturer make the required cutouts, particularly if in-house resources are limited.
Jim Krebs, technical marketer at AutomationDirect. Edited by Emily Guenther, associate content manager, Control Engineering, CFE Media, firstname.lastname@example.org.
- Electrical enclosure design features.
- How to customize electrical enclosures.
- Purchasing a customized electrical enclosure.
For you, would there be a lower total cost of ownership with ready-to-use enclosures?