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Main Isolator Switches for Distribution Board Isolation | 20A-125A | IEC 60947-3
Reliable and trusted main disconnect switch
KRIPAL manufactures main isolator switches in the UKP2 series for incoming supply isolation in residential and commercial distribution boards. These rotary-operated load-break switches provide a visible means of disconnecting the entire electrical installation from the supply, with rated operational currents from 40A to 125A at 230/400V AC and a utilization category of AC-22A per IEC 60947-3. The UKP2 features a double-break contact mechanism per pole that achieves a positive isolation gap exceeding 3mm in the OFF position, satisfying the isolation requirements of IEC 60364-5-53. The rotary handle provides a clear ON-OFF position indication with a padlockable OFF position for lockout-tagout compliance, and optional auxiliary contacts (1NO+1NC) for remote status signaling. The compact 2-module (36mm) or 4-module (72mm) DIN-rail format fits within standard consumer units and distribution boards, and the screw-clamp terminals accept cable cross-sections from 1.5 to 50 sq mm. CE and UKCA marked, KRIPAL main isolator switches are the standard incoming device for distribution boards where the supply authority does not provide an integral isolator in the meter cabinet.
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UKX-100 AC22A 230V Isolating Switch 100A 4 Pole
The UKX-40 AC22A 2Pole 230V AC Isolating Switch is a two-pole isolator for 230V AC circuits, compliant with IEC 60947-3 and GB/T 14048.3.
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UKX-100 AC22A 230V Isolating Switch 100A 1 Pole
The UKX-40 AC22A 2Pole 230V AC Isolating Switch is a two-pole isolator for 230V AC circuits, compliant with IEC 60947-3 and GB/T 14048.3.
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UKX-40 AC22A 230V Isolating Switch 40A 3 Pole
The UKX-40 AC22A 2Pole 230V AC Isolating Switch is a two-pole isolator for 230V AC circuits, compliant with IEC 60947-3 and GB/T 14048.3.
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UKX-40 AC22A 230V Isolating Switch 40A 2 Pole
The UKX-40 AC22A 2Pole 230V AC Isolating Switch is a two-pole isolator for 230V AC circuits, compliant with IEC 60947-3 and GB/T 14048.3.
Ask a QuoteMain Isolator Switch: Safe Distribution Board Isolation
A main isolator switch is the single disconnection point for an entire electrical installation, located at the origin of the installation (typically in the consumer unit or distribution board). Its function is to provide a guaranteed air-gap isolation between the supply and the installation for safe maintenance, emergency disconnection and firefighter isolation. Unlike a circuit breaker, an isolator switch does not provide automatic overcurrent protection; it is a manually operated device designed to be switched under load (rated making and breaking capacity) or used as an off-load isolator after the upstream protective device has disconnected the supply. IEC 60364 requires a main linked switch or linked circuit breaker at the origin of every installation, and the UKP2 provides this function in a compact modular format.
UKP2 Main Isolator Switch Series Technical Specifications
Current Rating and Load-Break Capability
The UKP2 isolator current rating is selected to match the installation’s maximum demand, typically 60A or 100A for a domestic consumer unit and 125A for a small commercial distribution board. The AC-22A utilization category means the switch is tested to make and break 1.5 times rated current at 1.05 times rated voltage under mixed resistive and inductive load conditions (power factor 0.65), ensuring the switch can safely disconnect the installation under full load without contact welding or excessive arcing. The rated short-time withstand current (Icw) is typically 3kA for 1 second, sufficient to carry the prospective short-circuit current at the origin of a domestic or light commercial installation until the upstream utility fuse clears the fault.
Isolation Gap and Safety Verification
The UKP2 double-break contact mechanism provides a minimum contact gap of 3mm per pole in the OFF position, exceeding the 2mm minimum isolation gap required by IEC 60947-3 for low-voltage switches. This gap is verified on 100 percent of production units by a dielectric withstand test at 2.5kV for 1 minute between the incoming and outgoing terminals of each pole. The rotary handle is mechanically linked to the contacts with a positive drive that prevents the handle position from indicating OFF if the contacts have welded closed (a condition that can occur if the switch is operated under severe short-circuit conditions). The handle can be padlocked in the OFF position with a shackle diameter up to 6mm, accepting up to three padlocks for multi-contractor lockout compliance.
Pole Configuration and Supply Type
The UKP2 is available in 1P, 2P, 3P and 4P configurations to match the supply type. Single-phase supplies (230V) use a 2P isolator that switches both the line and neutral conductors. Three-phase supplies (400V) without neutral use a 3P isolator, while three-phase supplies with neutral use a 4P isolator that switches all four conductors. Multi-pole units use a common toggle mechanism that mechanically links all poles, ensuring simultaneous operation. The neutral pole in a 4P isolator may be specified as “early-make, late-break” to ensure the neutral is connected first and disconnected last during switching, preventing a temporary overvoltage on single-phase loads if the neutral is lost while the phases remain connected.
Auxiliary Contacts and Remote Monitoring
The UKP2 can be fitted with an add-on auxiliary contact module (1NO+1NC changeover) that signals the isolator position to a building management system, fire alarm panel or remote monitoring system. The auxiliary contact is mechanically linked to the main contact toggle, providing a positive indication of the actual contact position (not just the handle position). For firefighter isolation switches installed at the building entrance per BS 9999, the auxiliary contact can signal the fire alarm panel that the building’s electrical supply has been isolated, confirming the action taken by the attending fire crew. The auxiliary contact is rated at 250V AC 3A for connection to building control system digital inputs.
Specify Main Isolators for Your Distribution Board
- Isolator Sizing: Provide your installation maximum demand and supply type, and we recommend the correct UKP2 current rating and pole configuration.
- OEM Board Integration: Source UKP2 isolators pre-assembled in your distribution board with connecting busbars and auxiliary contacts installed.
- Bulk Supply: Order UKP2 isolators in bulk packs of 50 for your panel building production line.
Distribution Board Main Isolation for Residential and Commercial
KRIPAL UKP2 main isolator switches provide the single-point supply disconnection for electrical installations in residential, commercial and light industrial buildings. As the device that an electrician, maintenance technician or firefighter operates to make the installation safe before working on it, the isolator’s reliability, clear position indication and padlock facility are directly linked to personnel safety.
Domestic Consumer Unit Main Switch
A UK domestic consumer unit uses a UKP2 100A 2P main isolator switch as the first device after the meter tails, providing the single point of isolation for the entire household installation. The electrician isolates the supply by switching the main isolator to OFF and padlocking it before replacing a consumer unit, adding circuits or performing an electrical installation condition report (EICR). The visible contact gap provides a higher level of safety assurance than a circuit breaker’s trip-free mechanism, which could theoretically close without warning if an internal spring fails. The 100A rating covers the typical 80-100A maximum demand of a modern household with electric cooking, heating and EV charging.
Commercial Distribution Board Incoming Isolator
A small commercial distribution board (shop, office, restaurant) uses a UKP2 125A 4P main isolator to disconnect the three-phase and neutral supply to the entire premises. The isolator is operated by the business owner or a designated responsible person in an emergency (fire, flood, chemical spill) to de-energize all electrical equipment before the emergency services enter the building. The clear ON-OFF handle position allows anyone, not just an electrician, to verify at a glance that the supply is isolated, and the padlock facility prevents unauthorized re-energization while maintenance or emergency response is in progress.
Renewable Energy Inverter AC Isolator
Grid-tied solar PV inverters require a dedicated AC isolator switch adjacent to the inverter, per IEC 60364-7-712, to allow the inverter to be isolated from the AC supply for maintenance, replacement or emergency disconnection. A UKP2 40A 2P isolator (for a single-phase 7.4 kW inverter) or 63A 4P isolator (for a 15-50 kW three-phase inverter) provides this function, with the rotary handle clearly labeled “PV Inverter AC Isolator” for identification by firefighters attending a building fire. The isolator is wired between the inverter AC output and the dedicated MCB in the consumer unit, providing local isolation without requiring access to the consumer unit which may be located in a different part of the building.
Temporary Construction Site Supply Isolator
A temporary construction site supply pillar uses a UKP2 125A 4P isolator as the main disconnection point for the site distribution system. The isolator is installed in an IP65 weatherproof enclosure at the site entrance, accessible to the site manager and the electrical contractor at all times. In the event of a site emergency or at the end of each working day, the site manager can isolate the entire site supply by switching the isolator to OFF and padlocking it, preventing unauthorized use of power tools and reducing the risk of cable theft from energized site distribution cables. The isolator must be visually inspected weekly for signs of damage or unauthorized tampering per the site electrical safety plan.
Swimming Pool Plant Room Supply Isolator
Swimming pool plant rooms with pump motors, filtration equipment and chemical dosing systems use a UKP2 63A 4P isolator as the local supply disconnection point. The isolator is installed adjacent to the plant room entrance door, allowing the pool operator to isolate all plant room equipment before entering for maintenance without needing to locate the remote distribution board. The isolator is labeled “Swimming Pool Plant Room Main Isolator” per BS 7671 requirements, and its operation is included in the daily pool safety checklist completed by the pool operator before opening the facility to the public.
Specify Isolator Switches for Your Project
- Application Review: Tell us about your installation and we recommend the correct UKP2 model with the right current rating and pole configuration.
- OEM Supply: Source UKP2 isolators pre-installed in your distribution boards with busbar connections and custom labeling.
- Bulk Packs: Order isolator bulk packs for electrical wholesaler distribution.
KRIPAL Main Isolator Manufacturing: Visible Safety
KRIPAL main isolator switches are manufactured on a rotary switch assembly line where the double-break contact mechanism, DIN-rail or panel-mount housing, and padlockable handle are produced, assembled, and tested under ISO 9001 quality management for global distribution board and switchgear isolation applications.
Double-Break Contact Mechanism Assembly
The isolator uses a double-break per pole contact design that provides visible isolation gap in the OFF position. Silver-plated copper contacts are assembled into a rotary cam-driven mechanism that provides snap-action switching independent of handle operating speed. Contact gap in the OFF position is verified on every unit to exceed the minimum isolation distance per IEC 60947-3.
Padlockable Handle and Door Interlock Integration
Handle mechanisms incorporate a padlock facility in the OFF position (lockable with up to three padlocks) and an optional door interlock that prevents enclosure door opening when the switch is ON. The interlock override mechanism for maintenance access is verified for correct operation across 500 test cycles on every production batch.
Dielectric Withstand Testing
Every main isolator switch undergoes a dielectric withstand test at 2500V AC between open contacts, between poles, and between live parts and the handle mechanism. Test voltage is applied for 60 seconds per IEC 60947-3, with leakage current monitored for any indication of insulation breakdown. Results are recorded against the serial number.
AC-23A Utilization Category Verification
Sample units from each production batch are tested for making and breaking capacity at the AC-23A utilization category (switching of motor loads or other highly inductive loads). The test circuit simulates the inrush current and power factor of a locked-rotor induction motor to verify that production units match type-tested switching performance.
Distributor Stock Holding Programs for Main Isolators
KRIPAL supports distributor inventory programs with agreed stock levels for standard main isolator switch models from 20A to 125A. Shipments are planned based on demand data, with scheduled replenishment to maintain stable supply and consistent fill rates.
Private Label and OEM Branding for Main Isolators
Laser-marked part numbers aligned with your catalog, OEM-branded packaging, and customized instruction sheets are available. Unbranded supply is provided upon request for private label production of main isolator switches.
Multi-Region Certification and Compliance Support
CE, UKCA, and IEC 60947-3 EN 60947-3 compliance documentation is provided according to target export markets. Technical documentation files are maintained and updated in line with evolving switchgear isolation regulatory requirements.
Direct Technical Access to KRIPAL Production Engineers
Your technical team communicates with the engineers who designed and tested your main isolator switches, not a distributor’s sales engineer reading from a catalog. Application questions including category selection for specific load types receive answers within 24 hours during China business hours.
Frequently Asked Questions
Explore FAQ >An isolator provides visible contact separation for maintenance safety. A circuit breaker automatically trips on overcurrent and may also provide isolation if rated for it.
A main circuit breaker can serve as an isolator if it has positive contact indication and is rated per IEC 60947-3. A dedicated main isolator switch provides superior visible isolation and padlock capability.
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