What it is and where it fits in the series
The Molex 391002304 is a 4-circuit, 2-row Eurostyle terminal strip in the 39100 series, rated 40 A per circuit at 300 V with a 0.472" (12.00mm) pitch. The enclosed barrier housing accepts 8-20 AWG wire via top-entry screws — zinc-plated steel under the head — with a closed bottom that prevents debris ingress in panel environments. Operating range is −40°C to 105°C in a white PA66 (Nylon 6/6) body rated UL94 V-0.
What the ratings mean for your selection
The 40 A per-circuit rating at 300 V is the primary commit point for the BOM line — the 8-20 AWG wire gauge range covers the conductors that will actually carry that current without undersizing the barrel. The enclosed barrier type is what separates this from an open-block design: it provides finger-safe coverage across the live bus in panel wiring, which matters in maintenance-access environments. PA66 construction with UL94 V-0 flammability rating satisfies the material requirement for most industrial enclosures. The 2-row layout at 12.00mm pitch is not a standard DIN rail foot-print; it mounts directly to chassis or panel via its body shape, so confirm the mounting hole pattern matches the existing installation before committing.
Sibling comparison — not a direct swap
The 391002304 shares its series with two peers but neither is a drop-in footprint replacement. The 0391002502 uses a 15.00mm pitch with only 2 circuits and a 63 A rating at 600 V — the larger pitch and higher voltage rating make it suitable for heavier feeder runs, not the same panel slot. The 0391002012 is a 12-circuit strip at 10.00mm pitch rated 30 A per circuit — more circuits in a tighter pitch but at lower current. Neither sibling swaps the 391002304 without adjusting wire routing, torque targets, and the circuit-to-position mapping in the harness or panel drawing.