Blog Post by Dan Peifer, Senior Engineer

Engineering specifications for many projects can be enormous.  Enclosure specification is just one of many things that can be overlooked with potentially costly repercussions.

You’ve no doubt heard the old adage, “Measure twice and cut once.” That advice has saved carpenters the world over countless hours of unnecessary and costly reconstruction.  This old carpenter’s proverb applies just as well to selecting the right sized enclosure for your automation project.

Luckily, when it comes to enclosure size specifications, you do have a luxury that carpenters don’t: You don’t have to be exact. However, please keep in mind that it’s almost always preferable to go a bit bigger than necessary, space permitting.

The Cost of Specifying an Enclosure Too Small

An error on the side of too small can be an expensive, time-consuming, and a difficult mistake to recover from. On the other hand, an error on the side of too large is not a problem and will avoid an unnecessary burden on everyone involved with the project.

In our business, accurate measurement comes from thorough planning. Too often, we have seen projects hampered early on because an engineer was not on hand to accurately estimate the proper enclosure sizing necessary. Undersized enclosures create an environment conducive to over-heating and over-crowding. Cooling devices such as fans, filters, and air conditioning needed to prevent over-heating can be pricey, messy, and even compromise the NEMA rating of the enclosure.

But more than that, going too small effectively pigeonholes you. It leaves you with no room for error and eliminates the possibility of making alterations in design. In addition to being expensive and time-consuming, these problems can be plain difficult to recover from. By addressing this early, you save yourself from a whole world of headaches in the future.

A Real Life Example

One recent project initially called for a wall mounted control cabinet measuring 48” x 32”. The final product was a freestanding, three-door 86” x 112” x 20” monster enclosure. The original specification did not take into account the room needed for all components and proper heat dissipation. Even with the larger size, spare space requirements had to be forgone to avoid adding a fourth door to the enclosure!

Had the original blueprint been more carefully considered, this particular team would have been spared the expenses associated with re-engineering the size of the motor control center, correcting drawings, rebidding the altered scope, and more.

Bottom Line

So when it comes time to consider enclosure sizing, think it through, and then think it through again. By effectively measuring twice, you’re sidestepping myriad roadblocks that only materialize to begin with as a result of poor planning. Adages only get passed down because they’re true, after all. So measure twice, and install once.