Plastic Screw Insulation Standards: Preventing Short Circuits and Optimizing Thermal Management in Electronic Devices

In Thailand's hot and humid environment, increasing component density raises the risk of short circuits on PCBs, and metal screws can make it harder to maintain required insulation clearance. This article outlines how plastic screws, with their electrical insulation and low thermal conductivity, can improve product safety while supporting compact equipment design.

Contents

• Preventing Short Circuits and Maintaining Insulation Clearance
• Selecting Plastic Materials with Electrical Insulation and Low Thermal Conductivity
• Key Considerations for Dielectric Breakdown Voltage and Operating Environment
• 60 Years of Experience and More Than 3,000 Standard Products
• How Nihon Chemical Screw Co., Ltd. Can Help

Preventing Short Circuits and Maintaining Insulation Clearance

As electronic devices become more compact, high-density mounting is now standard, but metal screws may unintentionally conduct electricity or contact nearby circuits, raising the risk of short circuits. Moisture and dust can also reduce insulation clearance, leading to tracking phenomena that compromise reliability — particularly in hot, humid environments like Thailand, where condensation may temporarily reduce insulation performance.

While insulation washers and spacers can be added to metal screws, they increase part count and assembly time. Plastic screws provide inherent electrical insulation, simplifying designs while improving safety, and their non-conductive, non-magnetic properties also help reduce electromagnetic interference (EMI).

Selecting Plastic Materials with Electrical Insulation and Low Thermal Conductivity

Plastic screws offer both excellent electrical insulation and significantly lower thermal conductivity than metal fasteners, making them effective where heat transfer from components to the PCB or enclosure needs to be minimized — for example, around power semiconductors or high-brightness LEDs, where plastic screws reduce thermal bridging to nearby temperature-sensitive parts.

Materials such as PPS (Polyphenylene Sulfide) and PEEK (Polyether Ether Ketone) combine low thermal conductivity with excellent heat resistance, maintaining mechanical strength even under continuous high-temperature operation. Material selection should be based on the application — ranging from general-purpose Polycarbonate (PC) to high-performance engineering plastics with superior chemical resistance and flame retardancy — matched against operating temperature and mechanical load for reliable long-term performance.

Key Considerations for Dielectric Breakdown Voltage and Operating Environment

Dielectric breakdown voltage — the maximum voltage an insulating material can withstand before failure — is a key insulation design parameter. Selected materials should provide sufficient safety margin above the circuit's operating voltage, especially in high-voltage applications.

Actual operating conditions matter too: in hot, humid environments like Thailand's manufacturing facilities, moisture absorption can affect insulation performance, so materials with low water absorption help maintain stable insulation over time. Beyond screw size (e.g., M1.7 or M2), designers should also evaluate volume resistivity and dielectric constant to optimize screw placement and insulation clearance on the PCB without increasing enclosure size. Defining the operating voltage and ambient temperature, then reviewing the material datasheet, are fundamental steps in selecting the right fastener.

60 Years of Experience and More Than 3,000 Standard Products

Even with a finalized design, stable supply is essential to keep production on schedule. Founded in 1965, Nihon Chemical Screw specializes in plastic fasteners and manages the entire process in-house — from mold design to production — enabling precise thread molding while maintaining mechanical strength.

The company stocks more than 3,000 standard products and accepts orders from a single piece, suiting prototyping, evaluation, and urgent design changes. Beyond its established Japan distribution network, products are also supplied across ASEAN via local distributors and trading companies. Custom manufacturing is available for non-standard shapes and engineering plastics outside the standard catalog, letting designers source insulation fastening solutions — from miniature screws to large bolts, washers, and spacers — from a single supplier for stable long-term procurement.

How Nihon Chemical Screw Co., Ltd. Can Help

As a specialist plastic fastener manufacturer, Nihon Chemical Screw supports insulation design for low-voltage electrical and electronic equipment through a wide selection of materials, including PEEK, PPS, RENY, and Polycarbonate (PC), addressing short-circuit prevention and thermal insulation challenges that metal screws cannot easily solve.

The product lineup spans ultra-miniature screws to bolts of M12 and above, plus washers and spacers, backed by an integrated in-house production system for consistent dimensional accuracy and quality in precision electronic applications. The company also continues developing advanced products such as the KYOUJIN Series, a high-strength engineering resin offering a lightweight, electrically insulating alternative to conventional metal fasteners.

To recommend the most suitable product, key conditions to consider are: operating voltage, ambient temperature, required thermal conductivity, and tightening torque. Please contact us for further technical consultation if these have not yet been determined.

*For more detailed information, please download the PDF attached to this article or contact us using the inquiry form at the bottom of the page.