MPI002/28

1. Overview

The Bulgin MPI002/28 is a 22mm stainless steel illuminated vandal-resistant pushbutton from Bulgin's MPI002 series (formerly Arcolectric), manufactured in Tunisia/China. MPI002 denotes ring illumination (vs. MPI001 = center-dot). The "/28" suffix specifies 2.8mm Quick Connect tab termination; other termination suffixes include /TE or /TERM (screw), /RP (solder tag), /FL (300mm flying leads). A voltage suffix (/6, /12, /24) means a current-limiting resistor is pre-installed; omitting it means no resistor — the user must calculate an appropriate series resistor. A complementary 16mm stainless steel range exists for tighter panels.

2. User Sentiment

No aggregated review data was found. In a documented DIY power amplifier build (A4 amplifier, Mark Hennessy), the MPI002/28/BL was chosen for its "vandal-proof stainless steel" aesthetics, LED color choice, and ring illumination. One practical issue noted: polycarbonate lens body has soft plastic that can deform during soldering in confined spaces. By 2024, pricing had risen sharply (Farnell £38.43+VAT, Rapid £33.01+VAT min 3 units), leading the author to question re-specifying it. The AMB epsilon24 audio community used it as a debounced power switch. A recurring user confusion point: it is momentary-only — requires external logic for latching power-switch behavior.

3. Real-World Applications

Designed for hostile environments: access control panels, security kiosks, public-facing equipment. MPI002/28/BL and MPI002/28/GN appear in the Brazilian Air Force (FAB) 2021 most-purchased parts list, indicating military/defense use. DIY audio builders use it for front-panel power switches. The IP66 stainless steel construction suits marine panels, industrial machinery, outdoor intercom/ATM, and tamper-resistant control surfaces.

4. Technical Specifications

• Type: Illuminated vandal-resistant pushbutton, SPST-NO, momentary push-to-make, tactile
• Contact rating: 50mA / 24V DC max
• Contact resistance: Max 100mΩ; Insulation resistance: Min 1000MΩ
• Dielectric strength: Contact-to-panel >2kV; contact-to-contact 1500V AC
• Operating force: 12N
• Panel cutout: 19.2mm; Body: ~Ø25.7×31.5mm overall; Ø22×32.7mm per listing
• IP rating: IP66 front panel seal (microswitch not sealed); IP67 noted in some CAD data
• Temperature: -30 to +70°C
• Life: 35,000 electrical cycles; 750,000 mechanical cycles
• Illumination: LED ring; colors: red (RD), green (GN), amber (AM), blue (BL), white (WH); dual-color: D1=red/green, D4=red/blue, D5=green/blue
• LED luminous intensity: ~1500mcd; LED Vf ~2V (blue), ~3.5V (green)
• Materials: Stainless steel body/button, polycarbonate lens, nitrile O-ring, copper alloy terminals, gold-plated contact plate
• Mounting torque: 0.5–1.5 Nm; RoHS compliant

5. Ordering & Compatibility

Retail pricing ranges ~£19–£38 (UK) or ~$9–$25 (LCSC/Asian). Available at DigiKey, Mouser, RS Components, Farnell/Newark, TME, Bürklin, Distrelec. Related: MPI001/28/{color} (dot illumination), MPI002/TERM/{color} (screw terminal). Voltage-specific variants (/BL/6, /BL/12, /BL/24) simplify wiring; base /BL requires external resistor. Lead times can reach 16 weeks at some distributors.

6. Known Issues

Polycarbonate lens body softens under soldering heat in tight assemblies. Momentary-only action causes recurring user confusion for those expecting latching behavior. Pricing has risen substantially, reducing cost-competitiveness for DIY use. Fixed-resistor variants require exact voltage matching to supply.