Schneider Electric XB4BA21 Black Flush Push-Button NO

XB4BA21: black flush NO Harmony XB4 push-button

The XB4BA21 is a Schneider Electric Harmony XB4 metal push-button for a 22 mm panel hole. It has a plain unmarked black head, a flush spring-return operator and a NO contact configuration. Seven Star LLC supplies the XB4BA21 in Oman and the GCC as an independent supplier based in Muscat, usually to panel builders and maintenance buyers who need a robust operator for control desks and machine panels.

The reference breaks down in a way the datasheet titles suggest, though the manufacturer’s ordering table is the final authority: XB4B is the metal 22 mm operator family, A is the flush push-button head, and the remaining digits carry the colour and contact selection. Black is conventionally a neutral, non-safety function such as jog, inch or a generic command, and it hides dirt on a busy desk better than lighter caps.

Selection checklist and RFQ information for XB4BA21

Send the points below so that the part number can be confirmed against the datasheet and checked for availability in a single reply.

• Required quantity and the full part number XB4BA21.
• Panel thickness and the position of any anti-rotation key or nameplate.
• Rear clearance behind the panel, checked against the body depth.
• Control voltage and current of the circuit the contacts will switch.
• Any approval needed by the project, such as marine or UL, compared with the datasheet.
• Delivery location in Oman or the GCC and the lead time you need.
• Confirmation that NO contacts and a black flush head match your circuit and legend.

Panel mounting and terminal wiring of the XB4BA21

The operator fits a standard 22.5 mm hole. The body measures 47 mm high, 30 mm wide and 52 mm deep, and weighs 0.08 kg, so the rear depth is the figure to check on shallow doors. The datasheet gives a tightening torque of 0.8 to 1.2 N.m for the terminals and lists screw heads compatible with Philips and pozidriv No 1 drivers as well as flat 4 mm and 5.5 mm blades.

Conductor capacity is up to two 1.5 mm² wires with cable ends, or single wires from 0.22 mm² upward without ends. The datasheet also states a resistance to a high-pressure washer of 7000000 Pa at 55 °C from 0.1 m, which is useful for food, beverage and marine-type duty, though a clean, undamaged seal against the panel is what makes the rating real in practice.

Contact ratings and life of the XB4BA21

The contact blocks are silver alloy (Ag/Ni). The thermal current is 10 A, the insulation voltage is 600 V at pollution degree 3 and the impulse withstand is 6 kV. Operational ratings include 3 A at 240 V and 6 A at 120 V in AC-15, and 0.27 A at 250 V and 0.55 A at 125 V in DC-13, with a 10 A gG cartridge fuse specified for short-circuit protection. These are control-circuit ratings: the contacts switch relay coils, PLC inputs and contactor coils rather than motors directly.

Electrical life is stated as 1 million cycles at 2 A, 230 V in AC-15, 3 A at 120 V and 4 A at 24 V, at up to 3600 operations an hour with a load factor of 0.5, plus 1 million cycles at 0.2 A, 110 V and 0.5 A, 24 V in DC-13. Mechanical life is 10 million operations. Electrical reliability for low-level signals is quoted at 1 mA and 5 V in a clean environment, a reminder to keep the contact atmosphere clean when the button feeds a PLC input.

Sealing, temperature and approvals of the XB4BA21

The chromium-plated metal bezel and zamak fixing collar give this operator a robust front face. The datasheet lists protection ratings of IP66, IP67, IP69, IP69K, and the unit is stated for UL type 4X/13 enclosures, so it can sit in washdown or dusty locations where a plain panel hole would not survive. Operating and storage temperatures are both given as -40 to 70 °C, a wide window that covers a summer-heated switch room as well as an unheated outdoor cabinet.

The approvals listed on the datasheet are CSA, LROS (Lloyds register of shipping), BV, UL listed, DNV. Marine and offshore projects often ask for the Lloyd’s Register, Bureau Veritas or DNV entries, but XB4BA21 should only be accepted against a requirement that appears on the datasheet for this exact reference. Vibration resistance is 5 gn between 2 and 500 Hz, with shock rated at 30 gn for 18 ms and 50 gn for 11 ms, figures worth quoting when the panel is mounted on a skid or on rotating plant.

Where XB4BA21 is used in Oman and the GCC

Metal push-buttons of this series are common on motor control centres, crane and hoist pendants, pump stations, packaged skids, conveyor panels and water treatment plants. In oil and gas and petrochemical sites they sit on local control stations and auxiliary panels; in desalination and power plants they appear on starter doors and operator desks. In practice the black head of the XB4BA21 is chosen for the function described earlier on this page, so keep the colour consistent with your legend.

The metal bezel resists knocks, sunlight and cleaning chemicals better than a plastic head, which matters on coastal sites where heat, dust and salt air are routine. Even so, mount the button where an accidental knock cannot operate it, or fit a protective collar if the plant standard asks for one.

How the XB4BA21 operates

The head is spring return: pressing it moves the contact block and releasing it lets the spring return the head to rest. The normally open contact closes after 2.6 mm of travel and the total stroke is 4.3 mm. The operating force at the point of electrical change is stated as 3.8 N. Contact operation is slow-break, which is normal for control-circuit buttons and means contact speed follows the speed of the finger rather than a snap spring.

The datasheet lists positive opening as not provided, so the part suits start, jog and signalling functions; use a positive-opening variant where a welded contact could be dangerous, such as in a stop circuit. For XB4BA21 the contact terminals are marked (13-14)NO under the ISO numbering.

Technical specifications of the XB4BA21

Documents and quotation

The Schneider Electric datasheet for the XB4BA21 is attached on this page for your technical file. It carries the electrical, mechanical and environmental data summarised above, together with dimension and wiring drawings.

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 check the datasheet against your project requirements before ordering.