Schneider Electric ZB4BG4 Key Switch Head, Key Out Any Position

ZB4BG4: Harmony XB4 key switch head

The ZB4BG4 is a Schneider Electric Harmony XB4 head for a key selector switch with 2 positions 90°, built on the ZB4 round chromium plated metal head and a Key 455 keylock. The part is one of the heads sold separately from its contact blocks. Seven Star LLC supplies the ZB4BG4 in Oman and the GCC as an independent supplier in Muscat for panel builders, OEMs and plant maintenance stores.

The key can be withdrawn in any position, which means the switch can be left in either state and still locked against tampering by taking the key away. The overall depth behind the panel is 72 mm, noticeably more than the 44 mm of a handle selector, because the lock barrel sits behind the face.

Key logic and withdrawal on the ZB4BG4

A key switch moves access control to the key itself. The key can be withdrawn in any position, which means the switch can be left in either state and still locked against tampering by taking the key away. The datasheet lists the lock as Key 455, which identifies the key type. When you add heads or spare keys to an existing station, confirm that the key type matches the locks already in service.

The head is a two-position device, turning through 90 degrees. Mechanical durability is quoted as 1000000 cycles, high enough for mode-changeover duty but not intended for continuous cycling.

Environmental data and approvals for ZB4BG4

The datasheet lists degrees of protection IP66, IP67, IP69, IP69K under IEC 60529 and impact rating IK06 with keyhole cover ZBGP, with the UL enclosure type given as 4X/13. Operating temperature is -40–70 °C and storage temperature -40–70 °C. Vibration resistance is 5 gn (f= 2…500 Hz) per IEC 60068-2-6 and shock resistance is 30 gn for 18 ms or 50 gn for 11 ms, half sine, per IEC 60068-2-27. The datasheet lists these certifications: CSA, DNV, BV, LROS (Lloyds register of shipping), UL listed. Standards named include EN/IEC 60947-1, GB 14048.5, EN/IEC 60947-5-1, EN/IEC 60947-5-4, UL 508, EN/IEC 60947-5-5.

The product environmental data section shows EU RoHS compliance. Warranty is given as 18 months. A single-piece pack measures about 5 cm per side, and the bulk carton holds 100 pieces. Country of origin on the datasheet is France.

Technical specifications of the ZB4BG4

Choosing ZB4BG4 among the key switch variants

The three key heads in this lane differ in position count, return behaviour and where the key may come out. That choice should follow the operating procedure, not just the wiring.

Where ZB4BG4 is used

Key heads appear wherever mode selection must be limited to trained or permitted staff: maintenance bypass, local-remote transfer, machine guard override, test or calibrate modes, and reset after a trip. Typical Gulf installations include switchgear doors, compressor skids, burner management panels, crane and hoist stations and water-treatment control panels. Panels in Oman and the GCC see high ambient temperature, dust, wash-down on offshore and coastal sites and humidity from sea air, so the ingress rating of the head matters as much as its electrical function.

Information to send with an RFQ for ZB4BG4

Please send the details below so that we can confirm the part number against its datasheet.

• Part number ZB4BG4 and quantity.
• Key withdrawal position the procedure requires.
• Number of positions and whether return to centre is needed.
• Key type matching existing locks, and the number of spare keys.
• Contact blocks to be fitted behind the head.
• Panel cut-out size and thickness, plus rear clearance for the 72 mm depth.
• Delivery location in Oman or the GCC and required lead time.

If you are replacing a head, a photo of the old head and its rear blocks helps to confirm that the replacement matches.

How ZB4BG4 fits the ZB4 head system

A complete station built around this unit has three parts: the head, a fixing and contact assembly on the back, and a legend plate or marking on the front. The Harmony XB4 range sells heads and blocks as separate items, which lets a panel builder keep one stock of blocks and choose the face of each control later. Because the ZB4BG4 is sold as a head only, always confirm the block part numbers and their voltage and current ratings for your circuit from the matching datasheets.

When the control scheme is reviewed, the head, the legend and the rear blocks should be documented together, since a panel that is modified later is much easier to maintain when each station can be identified by its head part number. For spares, hold a few heads of each type rather than whole stations, because the heads are the parts most exposed to knocks, sun and cleaning chemicals.

Installation and maintenance of ZB4BG4

Drill the panel to 22.5 mm and fit the head from the front, then clamp it with the collar or fixing blocks from the rear. Because the head carries no contacts, fit the contact or lamp blocks on the back only after the head is secured, and keep conductor ends clear of moving parts. Fit and torque the retaining parts as the datasheet’s mounting drawing shows; the drawing page gives the cut-out and clearance for the fitting.

During commissioning, operate this unit through its full range, check each contact state with a meter and confirm that the legend plate matches the function. In service, wipe the bezel clean, check seals during shutdowns, and replace any head that is cracked, loose or sticking. Keep a spare head in the maintenance store for panels that cannot be taken offline.

Documents and quotation

The Schneider Electric datasheet for the ZB4BG4, dated 8 Nov 2026, is attached on this page for your technical file. It lists the characteristics, environmental data and dimension drawings summarised above.

To request a quotation, send the part number and quantity through the enquiry form and we will reply with availability and delivery terms. Seven Star LLC is an independent supplier and does not act for the manufacturer, so please confirm that the datasheet data suits your project before ordering.