What this connector is
The Molex 391001812 is the 12-circuit, 8.00 mm pitch member of the Eurostyle 39100 enclosed barrier terminal strip series, rated 20 A per circuit at 600 V. Top termination is a screw-clamp entry; the bottom is closed. The white PA66 housing carries a UL94 V-0 flammability rating and operates from -40 °C to 105 °C.
Pitch and circuit count — what drives the fit decision
For a panel-mount barrier strip, the two ratings that govern fit are pitch and circuit count. The 0.315" (8.00 mm) pitch of the 391001812 sets the board footprint and wire-entry spacing — a tighter grid than the 0.394" (10.00 mm) pitch of the 0391002012 peer, which shares the same 12-circuit count but not the same panel cutout. The 12-circuit dual-row layout gives 24 individual wire entries, accepting 12-22 AWG per entry. The 20 A per circuit rating handles most industrial control-panel power-distribution nodes comfortably; the 600 V rating covers the mains-voltage range for which enclosed-barrier strips are typically specified.
Where enclosed-barrier terminal strips are used
Enclosed-barrier strips like the 391001812 sit in panel cabinets and chassis as the fixed wire-termination point for field wiring, power distribution rails, and equipment bonding. The enclosed housing adds finger-safe protection at exposed live terminals — a key requirement in industrial automation and process-control panels where maintenance personnel work adjacent to live circuits. The PA66 housing with zinc-plated steel terminal screws and the -40 °C start temperature suits outdoor or refrigerated equipment enclosures as well as factory floor installations.
Sibling comparison — 8 mm pitch vs 10 mm pitch at the same circuit count
The 0391002012 is the closest same-series peer by circuit count — also 12 circuits, also dual-row, also enclosed, also chassis-mount. But its pitch is 0.394" (10.00 mm), not 8.00 mm. That 2 mm difference per circuit compounds across 12 positions and means the panel cutout, wire-entry spacing, and overall strip length are all different — the 391001812 will not drop into a panel cutout made for the 0391002012 without rewiring. Current rating also differs: the 0391002012 is rated 30 A per circuit, so it has more headroom for higher-power distribution nodes, while the 391001812 at 20 A is better suited to control-circuit and instrument-power applications. Neither is a cross-reference for the other; they serve different panel geometries.