Introduction to the Haydon HAY‑MPRACDC‑8A and its key features
Haydon HAY‑MPRACDC‑8Ais a compact, universal AC/DC DPDT relay module engineered for reliable dry‑contact switching from low‑voltage control signals. Designed with installers and system integrators in mind, this module automatically selects AC or DC operation across a broad supply range and includes an LED to indicate the coil energised state. Its combination of flexibility, compact footprint and a practical contact rating makes it a versatile choice for access control, CCTV interfaces, door‑escape circuits and a wide variety of general automation tasks.
Key features at a glance:
- Universal AC/DC coil — automatic selection (no polarity or jumper required)
- Wide supply range: 9–30 VAC or 10.5–36 VDC
- DPDT contacts rated to 8 A (240 V AC / 30 V DC)
- LED energised indicator for visual status feedback
- Low nominal coil current (around 24 mA) for efficient control
The HAY‑MPRACDC‑8A is built around a universal coil that senses and adapts to AC or DC supply automatically. This removes the need to stock separate AC and DC relay variants, reducing inventory complexity for installers and maintenance teams. The coil accepts 9–30 VAC or 10.5–36 VDC, a range that covers many common control voltages found in building management systems, alarm panels, CCTV power supplies and access control power rails.
Electrical specifications and practical benefits include:
- Supply voltage:9–30 VAC / 10.5–36 VDC — accommodates both AC and DC control sources without modification.
- Coil resistance:360 Ω — a typical coil resistance that contributes to the nominal coil current of ~24 mA, keeping drive requirements modest and compatible with many controller outputs.
- Nominal coil current:24 mA — low current draw reduces the load on upstream power supplies and makes parallel driving of multiple relays from a single driver more feasible.
- Contact rating:DPDT, 8 A at 240 V AC / 30 V DC — robust enough for switching low‑voltage lighting, magnetic locks, alarm circuits and motor preloads within the rated limits.
- Minimum switching current:10 mA — suitable for switching small loads and interface signals without contact reliability issues under correct wiring.
- Indicator:LED (energised) — instant visual confirmation of coil activation helps during commissioning and troubleshooting.
From a mechanical perspective the module’s footprint (68 × 50 × 30 mm) is compact, making it suitable for control panels, DIN rail-adjacent assemblies or small enclosure deployments. While the provided mechanical data omits some mounting and connection specifics, the module’s size and form factor are typical for line‑level relay modules used in access and security installations.
Safety and installation:Always refer to the official datasheet for full electrical characteristics, wiring diagrams and approvals (manufacturer PDF: https://www.farnell.com/datasheets/4127831.pdf). Installation should be carried out by a competent electrician or technician. When switching mains voltages, ensure correct isolation and observe local wiring regulations.
The HAY‑MPRACDC‑8A is particularly well suited to environments where flexibility, reliability and compactness are required. Typical applications include:
- Access control systems:Switch magnetic door locks, release circuits or interface with alarm outputs. The universal coil eliminates concerns about whether the control board provides AC or DC, simplifying integration.
- CCTV and security interfaces:Control camera power rails, switch auxiliary devices (IR illuminators, heaters) or create logic interfaces between heterogeneous security subsystems.
- Door‑escape and life‑safety circuits:Use as a dry contact for emergency release interlocks and door control logic where a reliable mechanical contact is required.
- Building automation:Integrate with BMS controllers to switch HVAC actuators, lighting circuits or ventilation interlocks where a DPDT contact arrangement enables changeover or dual‑circuit control.
- General automation:Small machinery control, test rigs and prototyping where an 8 A DPDT contact provides adequate switching capacity and the universal coil simplifies supply planning.
Because of its LED indicator and modest coil current, the relay is particularly useful during commissioning and maintenance. The visual feedback reduces the time to confirm operation, and the low coil current lessens stress on control outputs and backup power supplies.
When selecting a relay module, buyers typically weigh coil type, contact rating, size and price. The HAY‑MPRACDC‑8A occupies a niche that balances flexibility and cost-effectiveness:
- Universal AC/DC vs AC‑only or DC‑only relays:Many relays are optimized for either AC or DC coils. The HAY‑MPRACDC‑8A’s universal coil removes the need to identify coil polarity or maintain separate stock for AC and DC, which can be a significant advantage in maintenance operations.
- Mechanical DPDT vs single‑pole relays:DPDT gives additional wiring flexibility (e.g., changeover contacts or dual circuits) compared with SPDT or SPST relays of similar size. For applications requiring two isolated circuits or changeover functionality, it can replace two single‑pole relays, saving space and wiring complexity.
- Versus solid‑state relays (SSRs):SSRs excel at silent switching and high switching frequencies, but they can have higher on‑state losses for AC loads, may require heat sinking for high currents, and rarely provide galvanic isolation like mechanical dry contacts. For many access control and safety circuits where true dry contacts are mandated, the mechanical DPDT relay remains the correct choice.
- Price and value:With a suggested retail price around $14.75 (cost price noted as $11.62), the HAY‑MPRACDC‑8A offers a competitive price point for a universal DPDT relay. Compared with higher‑current industrial relays or sealed contactors, it is more economical for low‑to‑medium current switching tasks.
There are no official customer testimonials provided here, but representative feedback from installers and system integrators working with similar relay modules typically emphasises the following points:
- Ease of integration:"The universal coil saved time during installation — no need to check whether the control output was AC or DC."
- Reliability:"Reliable dry contacts and a clear LED make troubleshooting straightforward in the field."
- Good value:"For basic access control and CCTV switching tasks, this gives the right balance of cost and capability."
- Compactness:"The small footprint allowed us to fit several relays into a compact control enclosure without crowding."
These comments are illustrative of common installer priorities and reflect why universal coil DPDT modules like the HAY‑MPRACDC‑8A are popular in the security and automation sectors.
The Haydon HAY‑MPRACDC‑8A combines practical engineering and everyday usability: a universal AC/DC coil, useful DPDT contact arrangement rated to 8 A, LED indication and a wide operating voltage range. These attributes make it a versatile, cost‑effective relay module for access control, CCTV, door‑escape circuits and a broad range of automation tasks.
For installers and integrators who need to minimise inventory complexity and ensure reliable dry‑contact switching across multiple control systems, the HAY‑MPRACDC‑8A is an attractive option. Its modest retail price (suggested at approximately $14.75) and competitive performance characteristics deliver strong value for projects that don’t require high‑power contactors or specialist relays.
Before installing, consult the official datasheet (https://www.farnell.com/datasheets/4127831.pdf) for complete electrical characteristics and wiring diagrams, and ensure installation is performed by qualified personnel in accordance with local regulations. With that due diligence, the HAY‑MPRACDC‑8A can be a dependable, flexible building block in many control and security systems.
