ERECTA SWITCH® by Compac Engineering
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50-NP-AC5 — NistorPac Solid State Relay — 1-Pack

Non-latching solid state AC relay, 24–240 VAC, 5 A with heat sink

SKU 50-NP-AC5 · Stock 5501432 · 1-Pack
1-Pack5-Pack
Net price — per unit · quantity breaks
QuantityPrice
1–10$47.74
11–20$45.83
21–49$42.96
50–74$38.20
75–99$33.41
100+$31.02
As low as $31.02 per unit. Prices from the current price file; no minimum order.
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Specifications
Switching modeS.P.S.T., normally open
Voltage range24 – 240 VAC, 50–60 Hz
Load rating — no heat sink0.75 A (inductive / tungsten / resistive)
Load rating — with heat sink5.0 A
Maximum surge15 A
Minimum load0.1 A
Sensor circuit resistance300 ohms max (other than load)
Sensor current2 mA typical
Voltage loss2 VAC typical
Leakage through load terminal< 6 mA
Power dissipation0.92 watt per amp switched
Dimensions1.500″ × 1.500″ × 0.955″ (38.10 × 38.10 × 24.25 mm)
Ambient temperature0 – 120 °F
TerminalsEurostyle® screw type
ComplianceRoHS compliant

Product Description

The 50-NP-AC5 NistorPac is a solid state AC switching relay designed expressly for OEM use. Reed switch sensors deliver a reliable, low-power contact closure but cannot directly drive pump motors, solenoids or high-current loads. The NistorPac bridges that gap: the sensor pilots the relay, and the relay switches the load. In other words it lets a reed switch sensor handle a bigger job than it can do by itself.

It has no moving parts, so it is silent, cannot suffer contact wear, and does not arc. It is a continuously powered device: in standby it draws a tiny amount of current — typically less than 0.001 A. When the sensor closes, supply voltage is switched through to the lamp, solenoid or motor, and the load stays on for exactly as long as the sensor circuit is complete.

Wiring

Eurostyle® screw terminals accept two wires from the voltage source, two from the load device and two from the sensor. Load connects to terminals A and F, line voltage to B and E, and the sensor to C and D. Control of the load is accomplished simply by completing and interrupting the sensor circuit between C and D. Optional wiring ferrules (50-BP-F series) make terminal block wiring easier. Use AWG 20 minimum for sensor circuits and AWG 18 minimum for line and load circuits, and fuse line and load circuits to the applicable equipment codes.

Heat management

NistorPacs dissipate roughly 0.92 watts per amp switched, and only while the load is on. Below 0.76 A the built-in heat sink is sufficient. Above that the relay must be attached to a supplemental heat sink or any cool metal surface of sufficient area to keep it from overheating — single-side area in square inches is (amps × 1.25)² on 1/16″ aluminium, with silicone grease at the interface. Mount away from high-heat sources and allow airflow in tight enclosures.

What you can drive it with

Any dry contact or passive SPST sensor will pilot a NistorPac — reed switches, float switches, bimetallic temperature switches, flow switches, magnetic contacts, thermostats and pressure switches. That makes it useful well beyond liquid level: thermal shutdown interlocks that cut power to a heating element on over-temperature, door and panel interlocks, pressure-triggered compressor or alarm stages, flow verification circuits, HVAC damper and blower control, and light-duty feeders or mixers driven from a simple contact closure.

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Frequently Asked Questions

Common Questions About This Product

What is the difference between a float level switch and a liquid level sensor?

A float level switch like the 50-NP-AC5 is a point-level device: a float rides the liquid and actuates a magnetic reed switch at a set height, giving a simple on/off signal — no power, no firmware, no calibration. "Sensors" usually means continuous measurement (ultrasonic, radar, capacitive). ERECTA SWITCH targets reliable discrete-point control.

What are the typical applications for the 50-NP-AC5?

The 50-NP-AC5 is used for pump start/stop control, high-level overflow protection, low-level dry-run protection, and tank or reservoir level alarms in OEM equipment. The modular ERECTA SWITCH system is built into laundry, HVAC, water-treatment, hydraulic, and chemical-handling machinery.

What liquid chemistries is the 50-NP-AC5 compatible with?

Choose the material to match the media: Polypropylene (PP) for general aqueous, acids, and bases; Acetal (AC/Delrin) for solvents, fuels, and hydrocarbons; Kynar PVDF (KR) for aggressive or harsh chemicals. Every ERECTA SWITCH model is offered in all three materials.

Is the 50-NP-AC5 a point-level or continuous-level device?

The 50-NP-AC5 is point-level — it provides a discrete on/off signal at a set height. For multiple switch points, use a multi-level extended-stem set (2-, 3-, or 4-level) instead of a single continuous sensor.

What mounting options are available for the 50-NP-AC5?

ERECTA SWITCH offers vertical top-mount, bulkhead, and extended-stem configurations, plus side-mounted single-point models. The mount style is part of the model number — select the configuration that matches your tank geometry.

How is the actuation level set on the 50-NP-AC5, and how accurate is it?

Point detection is repeatable and mechanical. The trip height on the 50-NP-AC5 is set by the 10-715 Precision Nipple, ordered separately in 1-inch increments (1″–70″), so you place the switch point exactly where the application needs it.