CUPAL Washers
Copper-aluminium bimetal washers M6 to M20 — 11 sizes in stock, from HUF 480 net. Galvanic-corrosion protection for bolted joints.
Why use a CUPAL washer?
When you bolt a copper cable lug onto an aluminium busbar, the two dissimilar metals come into direct contact. The result: galvanic corrosion that gradually loosens the joint and increases contact resistance. Heating, failure, even fire can follow. The CUPAL washer solves this: copper side to copper, aluminium side to aluminium — no corrosion.
A CUPAL washer is needed because direct contact between a copper cable lug and an aluminium busbar causes galvanic corrosion. The washer has a different metal on each side: copper towards the lug, aluminium towards the busbar. No contact corrosion, the joint doesn't loosen, resistance doesn't increase.
List prices — CUPAL washer (HUF, net)
| Bolt size | Outer dia. | Max. lug | SKU | Net list price |
|---|---|---|---|---|
| M6 | 16 mm | 120 mm² | CUPAL-ALAT-M6-16 | 508 Ft~ €1.43 |
| M8 | 18 mm | 120 mm² | CUPAL-ALAT-M8-18 | 480 Ft~ €1.35 |
| M10 | 23 mm | 240 mm² | CUPAL-ALAT-M10-23 | 790 Ft~ €2.23 |
| M10 (large) | 26 mm | 300 mm² | CUPAL-ALAT-M10-26 | 887 Ft~ €2.50 |
| M12 | 26 mm | 240 mm² | CUPAL-ALAT-M12-26 | 937 Ft~ €2.64 |
| M12 (large) | 30 mm | 400 mm² | CUPAL-ALAT-M12-30 | 1,321 Ft~ €3.73 |
| M12 (extra) | 46 mm | 500 mm² | CUPAL-ALAT-M12-46 | 2,752 Ft~ €7.76 |
| M16 | 35 mm | 500 mm² | CUPAL-ALAT-M16-35 | 1,441 Ft~ €4.06 |
| M16 (large) | 46 mm | 630 mm² | CUPAL-ALAT-M16-46 | 2,752 Ft~ €7.76 |
| M20 | 37 mm | 500 mm² | CUPAL-ALAT-M20-37 | 2,064 Ft~ €5.82 |
| M20 (large) | 46 mm | 630 mm² | CUPAL-ALAT-M20-46 | 2,752 Ft~ €7.76 |
All 11 sizes available ex stock. Net list prices, VAT not included; shipping calculated separately.
Prices are net list prices. Gross = net × 1.27 (27 % Hungarian VAT applies to HU-issued invoices).Volume discounts apply (50+ pcs) — request a tailored quote.
Effective: 2025-02-01
Which size do you need?
Pick by cable-lug cross-section and bolt size. Small lugs (≤120 mm²): M6 or M8. Mid range (≤240 mm²): M10 or the smaller M12 d=26 mm. High-current busbars (300-630 mm² lugs): the larger outer-diameter washers — M10 d=26, M12 d=30/46, M16 d=35/46, M20 d=37/46. The larger the lug face, the larger d₁ you need to cover the transition properly.
Custom geometry? — DXF-based washer →Custom-cut to any shape — no one else offers this
Circles, strips, rectangles or fully bespoke contours — we cut any shape from CUPAL sheet. Send your drawing or describe the dimensions, and we respond within 1 business day.
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