https://www.elehpd.com/blog Practical selection and specification guides for low voltage electrical components, industrial control gear and lighting. en Fri, 25 Sep 2026 00:00:00 +0000 ELEHPD https://www.elehpd.com/blog/relay-selection-guide https://www.elehpd.com/blog/relay-selection-guide How to choose a control relay: coil voltage (AC/DC), contact rating, 8-pin vs 11-pin sockets, and electromagnetic vs solid-state for panel builders. Mon, 28 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/terminal-block-sizing-guide https://www.elehpd.com/blog/terminal-block-sizing-guide How to size a terminal block: current rating, cross-section, creepage and clearance, and DIN-rail vs PCB types for panels and control gear. Sun, 27 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/switching-power-supply-24v-selection https://www.elehpd.com/blog/switching-power-supply-24v-selection Choosing a DIN-rail switch-mode power supply: wattage headroom, 24V vs 12V, single-phase vs three-phase, and protection for control panels. Sun, 27 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/motor-protector-vs-mcb https://www.elehpd.com/blog/motor-protector-vs-mcb Why a motor needs a motor protection circuit breaker (MPCB): starting current, overload and phase-failure protection that a plain MCB cannot give. Sun, 27 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/surge-protection-panel-guide https://www.elehpd.com/blog/surge-protection-panel-guide How to choose an SPD / surge arrester: Class I, II and III, where each goes in a panel, and why it needs a backup fuse. Sun, 27 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/contactor-ac1-ac3-ac4-selection https://www.elehpd.com/blog/contactor-ac1-ac3-ac4-selection How to choose an AC contactor: utilization categories AC-1/AC-3/AC-4, coil voltage, and why the same contactor has different ratings. Sun, 27 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/mccb-vs-mcb-selection https://www.elehpd.com/blog/mccb-vs-mcb-selection When a molded case circuit breaker (MCCB) beats a miniature (MCB): higher current, adjustable trips, and selective coordination. Sun, 27 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/rcbo-vs-rccb-vs-elcb https://www.elehpd.com/blog/rcbo-vs-rccb-vs-elcb RCCB, RCBO and ELCB explained: how they differ, when to use a combined RCBO, and Type AC / A / F / B for modern loads. Sun, 27 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/mcb-cable-sizing-guide https://www.elehpd.com/blog/mcb-cable-sizing-guide The practical rule for sizing a miniature circuit breaker: Ib ≤ In ≤ Iz, cable derating, and picking the trip type for the load. Sun, 27 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/fuse-selection-guide https://www.elehpd.com/blog/fuse-selection-guide How to size a fuse: gG vs aR fuse characteristics, rated current and breaking capacity, and how to choose cylindrical, blade or screw-type forms. Sun, 27 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/mccb-molded-case-circuit-breaker-sizing https://www.elehpd.com/blog/mccb-molded-case-circuit-breaker-sizing How to size a molded case circuit breaker (MCCB): frame size, breaking capacity, thermal-magnetic vs electronic trip, and pole count for panel builders. Fri, 25 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/surge-protective-device-selection https://www.elehpd.com/blog/surge-protective-device-selection Choose a surge protective device (SPD): Type 1 vs Type 2 vs Type 3, voltage protection level Up, In/Imax ratings and coordination with upstream breaker. Fri, 25 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/rcd-rcbo-rccb-residual-current-protection https://www.elehpd.com/blog/rcd-rcbo-rccb-residual-current-protection RCD, RCBO and RCCB explained for buyers: Type AC vs Type A, 30 mA vs 100 mA/300 mA, pole configurations, and when to specify an RCBO instead of an RCD plus MCB. Thu, 24 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/how-to-choose-digital-energy-meter https://www.elehpd.com/blog/how-to-choose-digital-energy-meter How to pick a digital energy meter or panel meter: single vs three-phase, accuracy class, direct vs CT connection, and what to specify for sub-metering. Wed, 23 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/importing-low-voltage-electrical-products-from-china https://www.elehpd.com/blog/importing-low-voltage-electrical-products-from-china What importers should confirm before placing a first order with a Chinese low voltage electrical manufacturer: OEM terms, compliance documents, HS classification, QC and shipping. Tue, 22 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/wire-ferrules-pre-insulated-terminals-sizing https://www.elehpd.com/blog/wire-ferrules-pre-insulated-terminals-sizing How to match wire ferrules and pre-insulated terminals to conductor size, choose the right crimp profile, and avoid the two failure modes that cause loose panel connections. Mon, 21 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/led-floodlight-vs-high-bay-warehouse https://www.elehpd.com/blog/led-floodlight-vs-high-bay-warehouse When a high-bay is the right choice and when a floodlight is, how to work out the lumens you actually need, and which IP and IK ratings a warehouse or yard requires. Sun, 20 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/switching-power-supply-selection-guide https://www.elehpd.com/blog/switching-power-supply-selection-guide How to size a switching power supply for a control panel: headroom for inrush, derating above 40 C, single vs multi-output, and when to choose a DIN-rail or enclosed unit. Sat, 19 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/photoelectric-vs-inductive-sensors-packaging-line https://www.elehpd.com/blog/photoelectric-vs-inductive-sensors-packaging-line Choosing between diffuse, retro-reflective and through-beam photoelectric sensors and inductive proximity sensors, with the mounting and shielding rules that prevent false triggers. Fri, 18 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/22mm-panel-cutout-pushbutton-guide https://www.elehpd.com/blog/22mm-panel-cutout-pushbutton-guide The 22 mm panel cut-out standard, contact configurations, momentary vs maintained operation, IP ratings on the front face, and how to specify an emergency stop correctly. Thu, 17 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/contactor-sizing-ac3-motor-duty https://www.elehpd.com/blog/contactor-sizing-ac3-motor-duty How to size a contactor for a motor using AC-1 and AC-3 utilisation categories, why the AC-3 rating is the one to quote, and how coil voltage and auxiliary contacts enter the order. Wed, 16 Sep 2026 00:00:00 +0000 https://www.elehpd.com/blog/mcb-type-b-c-d-trip-curve-selection https://www.elehpd.com/blog/mcb-type-b-c-d-trip-curve-selection The trip ranges behind Type B, C and D miniature circuit breakers, how to check discrimination against inrush, and why 6 kA is not always enough. Tue, 15 Sep 2026 00:00:00 +0000