May 5, 2023

You already know that electrical components need enclosures. Electrical enclosures protect the parts inside from corrosion, blunt force, fire risks, shock risks, and other issues. It’s a major factor for safety.
Once you have everything tucked away in a proper enclosure, it can sometimes be more difficult to work with those components. So if you have something like an electronic device that is enclosed, it could suffer from signal interference or other related issues.

How do you fix that?
Your best bet is to look into signal shielding for your enclosures.

What Is Signal Shielding?
Specifically, we’re talking about electromagnetic interference (EMI) and ways to prevent it. Any device that uses electricity produces electromagnetic noise, and a lot of electronic devices are quite sensitive to that noise.
With EMI shielding, you can block the noise and solve the problem.

How Do You Shield Electrical Enclosures?
One way or another, EMI shielding boils down to a single concept. You have to wrap the electronics in a conductive barrier. To skip an advanced physics lecture, any material that readily conducts electricity can block magnetic fields from passing through it (the full science is a little more complicated). So, if you need to stop EMI, you need to put a conductive barrier between the source of EMI and the device that is bothered by it.

In practice, there are three easy ways to shield common electrical enclosures.

In many cases, your best solution is to install a gasket in the enclosure. The gasket will sit inside the enclosure, and this means that the enclosure protects the gasket as well as the electrical components within.
Gaskets are commonly made of multiple layers. You’ll have an outer layer that is silicone, neoprene, or some other insulating material. Inside, you’ll have a conductive layer that is made from common metals. There are other ways to manufacture these gaskets, but the bottom line is that you’re installing a thin conductive barrier inside of the enclosure to block EMI.

Another option is to coat the outside of the enclosure. The simplest way is to coat the entire enclosure with a conductive metal like nickel or copper. You can also look into metallic paints. These are paints with conductive metals dissolved into them. The paint protects the metal from corrosion, but there is enough conductive material in the paint to block most EMI.
You can look into alternative EMI coatings as well, but these are the most common options.

You can also place the entire enclosure inside a Faraday cage. How does that work? You wrap the enclosure with a metallic covering. The most common choice is to use a conductive metal mesh (like a copper mesh). This allows you to add EMI protection to enclosures as you see fit.

The drawback to external Faraday cages is that the enclosure won’t be protecting the conductive material. This is a suboptimal choice for outdoor enclosures or enclosures in environments that exacerbate metal corrosion.