Plug Fuses 125 VAC ■ Fast-Acting or Time-Delay ■ 1/4 – 30 Amperes DESCRIPTION Edison-base plug fuses (WOO, TOO, and TLO series) have threaded metal shells and contacts similar to incandescent lamp bases. Fuseholders for Edison-base fuses have matching metal threads similar to standard light sockets. Type S fuses (SLO and SOO series) have nonmetallic threaded bases which fit matching nonmetallic threads in Type S fuseholders. Type S fuseholders are size-limiting, and will not accept Type S fuses with ampere ratings greater than the ampere rating marked on the Type S fuseholder. Type S fuses will not fit Edison-base fuseholders, nor can Edisonbase fuses be used in Type S fuseholders. Approvals: UL Listed plug fuses. Note: Although rated at 125 volts, NEC permits plug fuses to be used in circuits not exceeding 150 volts to ground. See NEC Article 240-E. GENERAL PURPOSE FUSES SAO Type S Fuse Adapters inserted into Edison-base fuseholders permanently convert them to Type S fuseholders. They accept Type S fuses only. SAO Adapter Rating SAO 1 SAO 1-1/4 SAO 1-6/10 SAO 2 SAO 2-1/2 SAO 3-2/10 SAO 4 SAO 5 SAO 6-1/4 SAO 15 SAO 20 SAO 30 APPLICATIONS The National Electric Code now permits Edison-base fuses to be used only for replacements in existing installations, and then, only when there is no evidence of overfusing or tampering. All new Edison-base fuseholders must have Type S fuse adapters installed before they are placed in service. Designed to prevent installation of wrong size fuses, Type S Adapters (SAO series) screw into Edison-base fuseholders so they may accept Type S fuses. Once installed the adapters cannot be removed. To prevent shunting of open fuses or overfusing, and to reduce nuisance fuse opening, it is recommended that SAO adapters with properly rated SLO or SOO series fuses be installed in all Edison-base fuseholders. AMPERE RATINGS ⁄4 3 ⁄10 4 ⁄10 1 ⁄2 6 ⁄10 8 ⁄10 1 1 11⁄8 11⁄4 14⁄10 16⁄10 18⁄10 2 21⁄4 21⁄2 28⁄10 3 32⁄10 31⁄2 4 41⁄2 5 56⁄10 6 61⁄4 7 8 9 10 12 14 15 20 25 30 2 3 5 6 8 10 AMPERE RATINGS 46 15 20 25 30 TLO Fuses are medium time-delay Edison-base fuses designed for general-purpose branch-circuit protection. See TOO and SOO fuses for motor protection. Use for replacement purposes only. 15 20 — ⁄10 – 1 3 ⁄10 – 11⁄4 — 18⁄10, 2 18⁄10 – 21⁄2 — 31⁄2, 4 31⁄2 – 5 7, 8, 9, 10 — — 3 TYPE S PLUG FUSES AMPERE RATINGS ⁄2 1 ⁄10 – 1 11⁄8, 11⁄4 14⁄10, 16⁄10 18⁄10, 2 21⁄4, 21⁄2 28⁄10, 32⁄10 31⁄2, 4 41⁄2, 5 31⁄2, 61⁄4 7, 8, 9, 10, 12, 14, 15 20 Only 20, 25, 30 3 See Littelfuse box cover units in the Miscellaneous Products section of this catalog. WOO Fuses are non-delay Edisonbase fuses, best suited for incandescent lighting, resistance heating, and general purpose circuits with no significant motor load. Not recommended for motor circuits. See TOO and SOO fuses. Use for replacement purposes only. 1 Other SOO Fuse Ratings Which Fit HOLDERS EDISON-BASE PLUG FUSES TOO Fuses are dual-element timedelay Edison-base fuses designed for motor and motor branch-circuit protection; also suitable for all generalpurpose circuits. Use for replacement purposes only. Accepts Fuse Ratings: 25 30 SOO Fuses are dual-element timedelay Type S fuses designed for motor and motor branch-circuit protection; also suitable for all general-purpose circuits. AMPERE RATINGS ⁄4 ⁄10 4 ⁄10 1 ⁄2 6 ⁄10 8 ⁄10 1 3 1 11⁄8 11⁄4 14⁄10 16⁄10 18⁄10 2 21⁄4 21⁄2 28⁄10 3 32⁄10 31⁄2 4 41⁄2 5 56⁄10 6 61⁄4 7 8 9 10 12 14 15 20 25 30 SLO Fuses are medium time-delay Type S fuses for general-purpose branch-circuit protection. AMPERE RATINGS 15 20 25 30