What Are Non-Insulated Terminals?

Non-insulated terminals are bare-metal connectors — typically made of copper or brass — designed for simplicity and affordability. They are ideal for enclosed systems, sealed control boxes, and cost-sensitive applications. They are compact, easy to crimp, and effective when external protection is already in place. However, they require precise crimping and may expose wires to shorts in harsh conditions.

What Are Insulated Terminals?

Insulated terminals have protective vinyl, nylon, or heat-shrink sleeve molded around the crimp barrel, providing electrical isolation, strain relief, and environmental protection.

Insulated terminals feature a protective sleeve around the barrel — often color-coded (red, blue, yellow) by wire gauge. They are ideal for exposed environments with moisture, vibration, or corrosion, offering enhanced safety, faster installs, and reduced wiring errors. Types include PVC, nylon, and heat-shrink for added durability.

Key Differences

Insulated terminals protect against accidental contact, moisture ingress, and vibration-induced shorts; non-insulated terminals rely on the enclosure or secondary sleeving for protection.

Standard color coding follows IEC and UL conventions:

•     Red: 22–16 AWG / 0.5–1.5 mm²

•     Blue: 16–14 AWG / 1.5–2.5 mm²

•     Yellow: 12–10 AWG / 4–6 mm²

Due to the additional insulating material and manufacturing processes, insulated terminals are generally more expensive than their non-insulated counterparts. The extra insulation may also require more space, which can be a limitation in applications with tight wiring constraints.

Crimping Tool Requirements

Using a non-insulated crimping die on an insulated terminal punctures the sleeve, creating a shock and short-circuit hazard — always match the die to the terminal type.

When to Use Each Type