Fabricating custom enclosures is one of our specialties at Ameritex. We’re a UL 508a-certified shop with a line of UL-listed enclosures. We can also self-certify custom metal fabrications that meet the criteria for a particular National Electrical Manufacturer Association (NEMA) rating.  

However, one common misconception is that as a UL-certified shop, we can list any enclosure quickly and easily. Here, we’ll explain the UL testing and approval process and review your options when you need an enclosure. 

Understanding the UL Testing and Approval Process 

NEMA-Rated and UL-Listed Enclosures

Most shops that fabricate UL-listed enclosures have a series of UL-listed designs that have already been tested and pre-approved. At Ameritex we understand that not all designs or applications are the same, so a best practice we follow is to build the biggest and most complex enclosure possible and send it off for testing and approval. We think of every possible use and application, then we design enclosures that will satisfy those needs. Once approved, any smaller and less complex enclosure is subject to automatic approval. 

Any enclosures that fall outside the scope of the approval require testing and approval to be UL-listed. Often, simple design modifications that we will help you with can bring a design within the scope of approval. There is also the option of having Ameritex self-certify enclosures following in-house testing. These enclosures will be shipped with an Ameritex label stating the NEMA rating instead of a UL label. 

Upon request, we can have custom metal fabrications UL-listed. This option adds to the customer’s cost and lead time. But for repeat products, the cost per part is minimal.

How to Get a UL-Listed Enclosure Quickly and Cost-Effectively

Here are some general guidelines to ensure your design is within the scope of Ameritex’s pre-approved UL-listed designs.  

1. Size

When you work with Ameritex, you have the freedom to design a relatively large UL-listed enclosure: approximately 8’H x 15’W with no depth limitations under particular circumstances, though there cannot be cutouts over 24” deep.

2. Thickness 

Sometimes, customers design enclosures with thin materials (like 14-gauge sheet metal) to reduce material costs. However, please note that our pre-approved designs specify 12-gauge material to prevent deflection. 

3. Hinges and latches

The locations and spacing of latches and hinges must align with our pre-approved designs. For example, if you designed an enclosure with three quarter-turn latches to seal the door, but the latch spacing doesn’t meet our requirements, we’ll need to add and reposition latches accordingly. 

Talk to Us about Your Custom Metal Fabrication 

If you want to learn more about designing an enclosure for the right NEMA protection rating, check out this blog post. Got an enclosure you’d like us to quote? Reach out today for our metal fabrication services!