NH fuse-bases are available for delivery in single-pole and three-pole designs and can be closely mounted in parallel rows. Each three-pole base is upplied with two phase-partition walls. NH fuse-links plugon covers which clip onto the contact springs can also be supplied for these bases. Plastic fuse-bases sizes 00 to 3 have a single-part plastic base while size 4 has a metal baseplate with 2 ceramic bases. The stable silver-plated contact springs are made of electrolytic copper and formed from one piece. Separate springing is provided by highly resilient captive steel springs, making the contact invulnerable to high thermal stress. Size 4 NH fuse-bases are designed for size 4 fuse-links with 8 mm contact blades. A microswitch (250VAC/10A, terminal size 6.3x0.8mm) can be used with NH fuse-links with striker, it operates when fuse melts or where there is no fuse-link. Indirect touch protection fuse bases: no microswitch possible. Rated impulse withstand voltage Uimp: 6kV / 8kV (sizes 00 / 0-4)