NEMA 3 vs. NEMA 3R Enclosures: Which One Do You Need?

Many forces in the world can do a lot of damage to an electrical device. To guard against water, dirt and other hazards, you need an enclosure that’s manufactured and tested to the demanding specs established by industry professionals.

The NEMA rating system is one great tool for deciding what kind of enclosure you need, and the NEMA 3 rating series is one of the most popular for its excellent balance of cost and performance features. Let’s find out what the NEMA 3 ratings are all about, and take a look at what options Polycase has to offer!

NEMA Enclosure

Deciding What You Need from a NEMA Enclosure

To determine which kind of enclosure is best for your application, you’ll first need to know what kind of performance and protection you need. (See our blog post if you need a quick primer on understanding NEMA ratings!)

Consider some of these key factors to help you make your decision:

  • Does your device need protection against water, and how much water is it likely to come into contact with?
  • Does it need protection against airborne particles like sand and dirt, and how much?
  • Does it need protection against salt water and other corrosion hazards?
  • Does it need protection against accidental personnel contact?

The NEMA system’s ratings each describe in detail which hazards an enclosure must protect against to meet that rating. Many engineers and designers have found that the NEMA 3 enclosure series offers a great balance between these factors. So, next, let’s dive in to what NEMA 3 is all about.

NEMA 3 Enclosures

The NEMA 3 series provides solid outdoor-grade protection in a variety of styles and feature sets. The basic NEMA 3 definition includes:

  • Protection against splashing and dripping water
  • Protection against precipitation like rain, snow and sleet
  • Protection against airborne dust and dirt particles
  • Protection against accidental contact from personnel

These are some of the most common hazards that many enclosures have to stand up to.

However, it’s important to also know what NEMA 3 enclosures don’t protect against:

  • Hose-directed water jets
  • Temporary or prolonged submersion
  • Explosions
  • Impacts (unless they also have an IK impact rating)

Polycase YQ-080604 model

Polycase YQ-080604 model.

NEMA 3R and NEMA 3RX Enclosures

Enclosure models with NEMA 3R and NEMA 3RX ratings are similar to the ones discussed previously, but with two key differences. 3R and 3RX models don’t offer the protection against windblown dust found in other NEMA 3 models. 3R and 3RX models also include a small drainage hole to prevent liquid accumulation within the enclosure.

This comes as a trade-off. NEMA 3R and 3RX enclosures don’t offer the protection against airborne particles that other NEMA 3 enclosures do. However, they sometimes come with some cost savings and include a drainage feature, so if airborne particulates aren’t a significant concern for you, but liquid accumulation is, a 3R or 3RX enclosure is often a good deal.

NEMA 3S Enclosures

The NEMA 3S and NEMA 3SX enclosure ratings are something of a special case, in that they include features found nowhere else on the NEMA chart. Specifically, enclosures with these ratings must have external mechanisms that are operable even when ice has formed on the outside of the enclosure.

If your device will be situated in an area where frequent ice-overs are a problem, and it also needs to remain operable even under icy conditions, the NEMA 3S and NEMA 3SX enclosure ratings are your best option.

NEMA 3 Enclosures from Polycase

At Polycase, we know that electrical engineers and designers need access to enclosures with many different NEMA ratings, and they need them quickly and at a fair price. We currently offer a number of great choices for our customers who need NEMA 3 enclosures including:

  • Polycase YH Series: A rugged, weatherproof, waterproof enclosure series constructed from tough polycarbonate making it corrosion-resistant. An all-plastic hinge design provides easy access your device, making this an ideal choice for pole mounted electrical enclosures.
  • Polycase YQ Series: Our YQ Series is another great example of professional-quality polycarbonate protection from Polycase. Its foam gasket provides an extra layer of defense against environmental hazards, and it offers great options and features including tamper-resistant screw close system, transparent covers and mounting feet and flanges.
  • Polycase HD Series: The HD Series is another NEMA 3-compliant enclosure that’s rated for great outdoor performance, even all the way up to the ultra-tough NEMA 6P standard. Looking sharp in heavy-duty black or gray polycarbonate, it comes standard with mounting flanges for easy attachment to walls or surfaces, but should not be used with rigid conduit.  

Polycase also offers accessories for our NEMA 3 enclosures, like DIN rail kits and pole mounting kits, to give our customers the easiest, smoothest and most complete all-in-one experience.

Polycase YH-100806 model

Polycase YH-100806 model.

From flying dirt to splashing water, Polycase’s NEMA 3 enclosures offer great protection against many common hazards to electronic devices. For more information on our products, including NEMA rating questions and detailed specs, contact Polycase through our website or give us a call at 1-800-248-1233!