Protecting Control Panels

| Michael Cinquino

Protecting Control Panels

The Brains of the Operation

Protecting your equipment is important and challenging in a manufacturing environment. Automated equipment and machines are typically controlled with a combination of electrical and mechanical systems. These systems consist of motion (e.g., moving, turning, picking, and placing) and a host of other applications. The brains behind these systems are typically found in a nearby control panel. This post will take a closer look at these control panels–specifically, looking at the enclosure.

Keeping Control Panels Safe

For a plant electrician or a factory maintenance person, the question is: How do I keep the brains in that control panel 100% safe? These control panels are typically found on a factory floor. There are an elevated number of mechanical hazards on a factory floor–everything from inattentive line workers to fork trucks or other material-handling vehicles. Depending on your industry, the factory floor might be very hot and/or humid. If you are in a factory that manufactures food or beverages, you face additional challenges like wash-down procedures.

Control Panel & Enclosure Guide

What is Wash-Down?

Stainless Steel EnclosuresWash-down is a high-pressure cleaning with water and/or chemicals designed to kill bacteria and other microorganisms. If you are in the food and beverage industry, you already know that there is increased scrutiny being placed on wash-down and on product safety and contamination issues. Just in the past few years, many manufacturers have responded with intensified wash-down practices:

  • Greater frequency
  • Higher wash pressures
  • Higher wash temperatures
  • More concentrated chemical applications

How Does a Wash-Down Procedure Impact My Control Panels?

Enclosure CutoutsHopefully, a wash-down procedure will not impact your control panels at all. The enclosure of each control panel will have a NEMA rating. Even though there might be very high-pressure water very near to your control panel, there are ratings in place to help you use an enclosure appropriate for your environment. For this post, we’ll discuss NEMA Type 4X enclosures. A full outline of the different types can be found here for further reading.

Type 4X enclosures are constructed for either indoor or outdoor use to provide a degree of protection with regard to the ingress of water and against corrosion; for example, this type of enclosure is used in dairies and breweries–as well as outdoors in an area like a ship dock or in a wastewater treatment plant.

As one becomes familiar with electrical enclosures, you will notice that Type 4X enclosures are often found constructed of stainless steel. This is opposed to the more common “mild steel” enclosures found elsewhere. Stainless steel is typically the material of choice for wash-down environments. That isn’t really news to anyone who works in a wash-down plant; those facilities are sometimes stainless steel as far as the eye can see. If you are someone who works to install or maintain equipment in such a facility, you may know how difficult stainless steel is to work with–it is tough to machine, tough to drill, and tough to tap. It can be very tricky to do any sort of cutout work in a stainless steel enclosure.

A Quick Review of Stainless Steel

  • 304 is the most common stainless steel. It contains both chromium and nickel in relatively large percentages. It has a higher corrosion resistance than regular steel. Also worth noting, it is not very electrically or thermally conductive and is non-magnetic.
  • 316 is the second-most-common stainless steel after grade 304. 316 is sometimes referred to as “marine grade,” and some of its subtypes are considered “surgical steel.” It is more corrosion resistant than other common stainless steels and provides greater resistance to pitting.

Stainless Steel Electrical Enclosures

So, you have a control panel. It contains all sorts of automation intelligence: drives, PLCs, power supplies, terminal blocks, modules and so forth. This control panel is out on the manufacturing floor; it needs to be housed in a NEMA 4X Type enclosure. To install it, you may need a variety of custom cuts–knockouts for input wires and output wires, square cutouts for an interface or touchscreen and maybe circular cutouts with keyhole notches for push-buttons. These custom cuts are typically very specific and unique to your equipment.

Custom Control Panels

If your enclosure is a 304 or 316 stainless material, your in-house team might have a hard time doing these cutouts in a timely fashion–it takes a while to cut stainless. Or, if you make a cut wrong and have to scrap a piece, stainless steel enclosures can be a costly piece to waste.

Sometimes, it just makes sense to have your enclosures hit your factory floor ready for wiring, with all of the custom machining already done. This can be especially true of stainless steel enclosures. The team at Horizon Solutions works closely with Pentair/Hoffman to offer a range of options for custom enclosures. We can quote on any size enclosure and can incorporate any number of customer cutouts to your enclosures–this can be for one piece or five or more. Horizon Solutions has the in-house capability to do much of this work. We are a Hoffman Certified Modification Center.

Our team is here as an additional resource to work with you to get you the enclosures you need. We can work with CAD drawings and blueprints and make parts to your specifications. We can also work to design/build an enclosure or control panel based on your input and concept ideas.

Stainless Steel Machining Time Example

Let’s take a look at a sample stainless steel enclosure–this is a fictional example, as we do not share customer details. You will find this example is close to the real world, although your actual times may vary.

Enclosure, 16in x 14in x 6in deep, continuous-hinge

  • Side 1 (front): one (1) 4in x 3in cut out for HMI + two (2) circular cutouts for push buttons
  • Side 2 (left): two (2) knock-out holes 22mm
  • Side 3 (right): one (1) specially sized cut out for patch kit + four (4) drilled and tapped holes
  • Side 4 (top): no additional machining required
  • Side 5 (bottom): no additional machining required
  • Side 6 (back): no additional machining required

Our estimates would predict that doing all of those operations manually would take 7.12 hours and cost close to $400 in personnel time and shop resources–that is in addition to the cost of the enclosure itself. When a custom enclosure is required, you or your workers have to perform the following operations: layout, masking, drilling pilot holes, center punch, sawing, step drilling, deburring and other clean up.

Need Help Protecting Control Panels?

In the example above, Horizon Solutions could complete all of the required operations on your workpiece. We could do these in our CNC equipment. With a typical turnaround, we would have this project completed in two to three days and we could quote the work at around $100. Contact us for a custom quote.