Eaton E47BMS04 Precision Limit Switch

The E47BMS04 contacts are rated 15A at 250 Vac and 6A at 30 Vdc, so a standard 120V or 240V starter coil is well inside the switch's capability and no interposing relay is needed for coil-level loads. On DC control circuits, stay inside the 6A at 30 Vdc figure. Maximum AC current is 15A.

It is a 1-SPDT (Form C) switch, which gives you one common terminal plus a normally open and a normally closed contact. That lets you run one circuit that makes on actuation and another that breaks on actuation from the same switch body, though both share the single common pole. Wiring is at screw terminals.

The E47BMS04 uses an extended straight plunger, which is for a cam, slide, or machine member that approaches the switch head-on, straight into the plunger axis. If your target travels across the switch rather than into it, a plunger will take a side load it isn't built for and a roller lever or roller plunger head is the right choice instead. The extended plunger also buys you standoff distance so the switch body can be mounted back from the contact point.

No. The E47BMS04 carries a NEMA 1 environmental rating, which is general-purpose indoor enclosure protection against incidental contact and falling dirt only. It is not sealed against water, washdown, dust, oil, or coolant. For outdoor, washdown, or wet machine-tool duty you need a sealed oiltight or watertight limit switch instead.

The switch body measures 1.94 in length, 1.36 in height, and .69 in width, so it fits tight machine guarding and panel-interior positions. Allow additional clearance beyond the body for the extended straight plunger travel and for the screw terminal wiring.

Operating temperature on the E47BMS04 runs -13 to 176 F (-25 to 80 C), which covers unheated storage and loading-dock environments as well as hot motor rooms and oven surrounds up to 176 F. The enclosure is mineral filled phenolic, so it tolerates that heat range without softening. Keep in mind the NEMA 1 rating still limits it to dry indoor locations regardless of temperature.

Yes. Operating speed is specified from 0.01 mm/s up to 1 m/s, so it will transfer dependably on a creeping jack, screw drive, or slow gate as well as on fast-cycling machine motion. That slow-speed capability is what separates a precision snap-action switch from a general-purpose one on slow travel applications.

Order it as Eaton E47BMS04, part of the E47 series of precision limit switches. The E47 family is differentiated primarily by actuator head and contact arrangement, so the BMS04 suffix is what gets you the extended straight plunger with 1-SPDT (Form C) contacts rather than a lever or roller version.

Wiring is direct to screw terminals on the switch, so there is no pre-wired lead or quick-disconnect connector included. Plan on bringing your own conductors to the terminals and providing the raceway or conduit protection the installation needs, since the NEMA 1 housing offers only general-purpose indoor protection at the entry.