Insulating Isolation Washer Sets
Washer-and-sleeve isolation sets that electrically separate the fastener from the mounted component — flat, sleeve, cup, countersunk, perforated and pronged styles in ceramic, fiberglass, hard fiber, mica and plastic, covering screw sizes from No. 00 through 1/4" (inch and metric).
Last updated: 2026-11
Specifications
An isolation washer set does a job a plain washer cannot: it breaks the electrical path between the screw and the part it mounts. The set pairs an insulating washer under the head with an insulating sleeve through the hole, so neither the shank nor the head touches the chassis — the standard remedy when a grounded housing would short a sensor body, a bus bar, an anodized or painted enclosure that must stay isolated, or a galvanically mismatched pair of metals. Styles span flat, sleeve, cup, countersunk, perforated and pronged washers; materials run from hard fiber and plastic for everyday isolation to mica and ceramic where temperature climbs. Coverage starts at the smallest instrument screws — No. 00 — and runs through 1/4", in both inch and metric systems, which is why these sets are the default kit for electrical and electronics assembly work.
| Function | Electrically isolates the screw from the mounted component — washer and sleeve together break the metal path |
|---|---|
| Styles | Sleeve, flat, cup, countersunk, perforated and pronged washers |
| Materials | Ceramic, fiberglass, hard fiber, mica, plastic |
| Screw size coverage | No. 00 through 1/4" (inch); metric series offered alongside — both systems in the same catalog line |
| Sleeve geometry band | Sleeve ODs from 0.112" to 0.209"; sleeve heights from 0.015" to 0.063" across the range |
| Performance options | Electrical insulating, flame retardant, acid resistant, chemical resistant grades |
| Typical applications | Sensor and instrument mounting, bus bar standoffs, enclosure electronics, galvanic isolation of mixed-metal assemblies |
Materials
- Ceramic
- Fiberglass
- Hard fiber
- Mica
- Plastic
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (Insulating Isolation Washer Sets) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
When do I need a full isolation washer set instead of just an insulating flat washer?
When the fastener shank itself can complete the circuit. A flat insulating washer under the head isolates only one end — the shank still passes through the mounting hole and, in a conductive housing, touches its wall. If the hole is in metal, the set is the correct answer: the insulating sleeve lines the hole so the shank never contacts it, while the washer isolates the head. For mounting onto a non-conductive surface, a plain insulating flat washer is sufficient and the set adds cost without adding isolation.
What is the MOQ and lead time for this washer type?
The minimum order quantity is 10,000 pieces. Stock items ship in 3–7 days; non-stock items are confirmed at quotation. Common sizes in this washer type are widely stocked; confirm the exact schedule against quantity and size mix at quotation.
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support