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Fuse Holders and Fuse Links for Power Distribution | 32A-630A | NH Cylindrical
KRIPAL Fuses are designed for AC 50Hz systems with a rated insulation voltage up to 690V and a conventional thermal current up to 125A.
KRIPAL manufactures fuse holders and fuse links in the UKF1 series for low-voltage overcurrent protection in residential, commercial and industrial distribution boards. The fuse holder range includes D-type (Diazed) screw-in fuse bases for rated currents up to 63A, NH-type blade-contact fuse switch-disconnectors for rated currents from 63A to 630A, and cylindrical fuse holders for 10x38mm, 14x51mm and 22x58mm fuse-links. These fuse holders accept gG (general purpose) and aM (motor protection) fuse-links per IEC 60269-1, providing both overload and short-circuit protection with breaking capacities up to 100kA at 400V AC. The UKF1 NH fuse switch-disconnectors feature a visible isolation gap when the fuse-link carrier is removed, satisfying the requirement for a lockable main switch in distribution boards. KRIPAL fuse holders are manufactured with ceramic or glass-fiber reinforced polyamide bodies for high arc containment, silver-plated copper contacts for low contact resistance, and IP20 finger-safe terminals per IEC 60529. CE and UKCA marked, these components are used by distribution board manufacturers for incoming supply protection, sub-main protection and high-breaking-capacity circuit protection where MCBs would not provide adequate fault current interruption.
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UKRT18 AC Fuse Holder 1P/2P/3P 125A for 22 x 58 Fuse CE Certified
It is primarily used in electrical circuits as a support for various fuse-links (such as types gG, aM, aR, etc.) with dimensions up to 22×58.
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UKRT18-63 AC Fuse Holder 63A 1P/2P/3P for 14 x 51mm Fuse CE Certified
It is primarily used in electrical circuits as a support for various fuse-links (such as types gG, aM, aR, etc.) with dimensions up to 22×58.
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UKRT18-32 Fuse Holder 32A 1P 2P 3P for 10x38mm Fuse CE Certified
It is primarily used in electrical circuits as a support for various fuse-links (such as types gG, aM, aR, etc.) with dimensions up to 22×58.
Ask a QuoteFuse Holder and Fuse Link Technical Guide for Industrial Protection
A fuse holder, also known as a fuse base or fuse switch-disconnector, provides the mechanical mounting and electrical connection for a fuse-link. The holder must securely retain the fuse-link, provide low-resistance contact between the fuse-link end-caps and the circuit conductors, contain the arc energy during fuse operation, and (in the case of switch-disconnectors) provide a means of safely withdrawing the fuse-link to isolate the circuit. NH-type fuse switch-disconnectors combine the fuse holder with an integrated load-break switch, allowing the operator to safely disconnect the circuit under load by withdrawing the fuse-link carrier to the isolated position. This selection guide covers fuse holder type, rated current, fuse-link compatibility and switching capability.
UKF1 Fuse Holder Series Technical Specifications
Fuse Holder Type Selection by Application
D-type (Diazed) screw-in fuse holders (D01, D02, D03 sizes, 2A to 63A) are used in domestic and light commercial consumer units for incoming supply and sub-main protection, where their compact screw-in format fits within a standard DIN-rail consumer unit. NH-type blade-contact fuse switch-disconnectors (size 00, 0, 1, 2, 3, 63A to 630A) are used in industrial distribution boards and motor control centers, where their higher current rating and integrated load-break switch function provide both overcurrent protection and circuit isolation. Cylindrical fuse holders (10×38, 14×51, 22x58mm, 2A to 125A) are used for control circuit protection inside industrial panels, where their compact form factor fits alongside contactors and relays on a DIN-rail. The fuse holder must be rated for the same or higher current and voltage as the fuse-link it will contain.
NH Fuse Switch-Disconnector Load-Break Capability
The UKF1 NH fuse switch-disconnector is tested to IEC 60947-3 for load-break switches with a utilization category of AC-22B (switching of mixed resistive and inductive loads, including moderate overload). This means the switch can safely disconnect a circuit carrying rated current at rated voltage without the fuse-link needing to operate. The load-break mechanism uses a spring-assisted quick-make/quick-break action that operates independently of the operator’s hand speed, ensuring consistent contact separation speed and arc extinction regardless of whether the operator pulls the handle quickly or slowly. The switch is padlockable in the OFF position with up to three padlocks (6mm shackle) for multi-contractor lockout-tagout compliance during maintenance of downstream equipment fed by the fuse-protected circuit.
Fuse-Link Types and Utilization Categories
gG (general purpose, formerly gL) fuse-links provide full-range protection against both overload and short-circuit, and are the standard choice for cable and equipment protection in distribution circuits. Their time-current characteristic is defined in IEC 60269-1, with a conventional non-fusing current of 1.25 In and a conventional fusing current of 1.6 In for ratings up to 4A, and 1.25 In non-fusing and 1.6 In fusing for ratings above 4A. aM (motor protection) fuse-links provide short-circuit protection only and must be used with a separate motor overload relay, because they do not operate on overloads below approximately 4 In. They are selected based on the motor starting current, with the fuse rated at approximately 1.5 times the motor full-load current to avoid nuisance blowing during DOL start. gR (semiconductor protection) fuse-links provide ultra-fast short-circuit protection for power semiconductors with very low I squared t let-through, typically clearing within half a cycle at 10 times rated current.
Breaking Capacity and Back-Up Protection
NH fuse-links achieve a breaking capacity of 100kA at 400V AC, sufficient for any low-voltage installation regardless of the prospective short-circuit current at the supply transformer terminals. This high breaking capacity makes fuses the preferred protection device for incoming supply circuits where an MCB’s 10kA or 25kA breaking capacity may be insufficient. The fuse holder must be rated for the same breaking capacity as the fuse-link it contains, verified by type testing with the specific fuse-link type. The UKF1 NH fuse holders are tested for 100kA conditional short-circuit current in combination with NH gG fuse-links from KRIPAL’s approved fuse-link supplier, and the test report specifies the maximum fuse-link rating that can be used in each holder size.
Specify Fuse Holders for Your Distribution Board
- Fuse Holder Selection: Provide your circuit requirements and we recommend the UKF1 holder type, size and compatible fuse-link rating.
- Coordination Study: Request time-current curves for upstream fuse / downstream MCB discrimination verification.
- OEM Bulk Supply: Source UKF1 holders and fuse-links in bulk for your panel building production line.
Fuse Protection for Switchboards, MCCs and Distribution Panels
KRIPAL UKF1 fuse holders and fuse-links provide high-breaking-capacity overcurrent protection at every level of low-voltage power distribution, from the main incoming supply in a domestic consumer unit to the motor feeder in an industrial motor control center. The combination of a robust mechanical holder and a precisely calibrated fuse-link provides reliable protection that does not degrade over time and does not require periodic testing beyond visual inspection.
Domestic Consumer Unit Main Incoming Fuse
UK domestic consumer units use a UKF1 D-type fuse holder with a 60A or 80A gG fuse-link as the main incoming overcurrent protection, connected between the meter tails and the consumer unit busbar. The fuse provides discrimination with the downstream MCBs: an overload or short-circuit on any final circuit trips that circuit’s MCB, and the 60A main fuse only operates if the total installation load exceeds 60A or if a fault occurs on the consumer unit busbar itself. The D-type screw-in holder ensures that the householder cannot replace the fuse-link with one of a higher rating without a special tool, preventing the dangerous practice of “up-fusing” that overloads the meter tails.
Industrial Distribution Board Incoming Supply Protection
An industrial distribution board with a 400A incoming supply uses a UKF1 NH size 2 fuse switch-disconnector fitted with 400A gG fuse-links. The 100kA breaking capacity of the NH fuse-links safely interrupts the maximum prospective fault current at the board incomer (which can reach 50-80kA if the board is located close to the supply transformer), providing back-up protection for the downstream MCBs and MCCBs which may have lower breaking capacities. The integrated load-break switch function allows the electrician to isolate the entire distribution board for maintenance by withdrawing the fuse-link carrier to the isolated position, without needing a separate upstream isolator switch.
Motor Control Center Feeder Protection
Motor control centers (MCCs) use UKF1 NH fuse switch-disconnectors with aM (motor protection) fuse-links to protect each motor feeder against short-circuits, with the motor overload protection provided by a separate thermal overload relay in the motor starter. A 22 kW 400V three-phase induction motor (42A full-load current) uses a 63A aM fuse-link that withstands the motor starting current of approximately 250A for 5-10 seconds during DOL start, but clears a bolted short-circuit at the motor terminals within half a cycle. The fuse switch-disconnector provides local isolation for the motor feeder, padlocked in the OFF position while maintenance personnel work on the motor or the driven machinery.
Building Riser Cable Protection
Multi-story buildings use UKF1 NH fuse switch-disconnectors at the base of each vertical riser cable that supplies power to the floor distribution boards. The fuse-link rating is selected to protect the riser cable’s current-carrying capacity, with a 160A NH size 00 fuse-link protecting a 70 sq mm copper riser cable. The fuse switch-disconnector at the base of the riser serves as the main isolation point for the entire floor, and the fuse-link provides back-up short-circuit protection for the floor distribution board’s incoming MCB or MCCB. The fuse time-current characteristic is coordinated with the upstream main board protection and the downstream floor board protection to ensure that a fault on the riser cable clears the riser fuse without tripping the main board incoming device and without relying on the floor board devices.
Control Panel Internal Circuit Protection
Industrial control panels use UKF1 cylindrical fuse holders with 10x38mm or 14x51mm gG fuse-links to protect individual control circuits: PLC power supply (2A), contactor coil circuits (4A), HMI panel (2A), and 24V DC power distribution (10A). The compact cylindrical format fits on the DIN-rail alongside the contactors and relays, occupying only 8-10mm of width per holder. The fuse provides both overcurrent protection for the control wiring (which is typically 1.0-1.5 sq mm and cannot withstand the full short-circuit current of the panel’s main supply) and a means of isolating individual control circuits for testing and fault-finding by removing the fuse-link from the holder.
Source Fuse Holders for Your Panel Building Operation
- Fuse Specification: Provide your circuit schedule and we specify the correct UKF1 holder and fuse-link type, size and rating for each circuit.
- Discrimination Tables: Request upstream/downstream fuse discrimination data to verify selectivity in cascaded protection schemes.
- Bulk Fuse-Link Supply: Order UKF1 holders complete with factory-fitted fuse-links of your specified rating for JIT delivery to your assembly line.
KRIPAL Fuse Holder Manufacturing: Precision Contacts for Reliable Protection
KRIPAL fuse holders and fuse links are manufactured in a dedicated production cell where the ceramic fuse holder body is molded and glazed, contact clips are stamped from phosphor bronze, and fuse links are assembled with precision element and quartz sand filling. Each production batch undergoes contact resistance and temperature rise testing for global industrial power distribution applications.
Ceramic Fuse Holder Body Molding and Glazing
Fuse holder bodies are formed from steatite ceramic using dry-press molding, then fired in tunnel kilns and glazed for surface insulation. The ceramic formulation provides high mechanical strength and arc resistance (CTI above 600V). Dimensional inspection on sample bodies verifies fit with standard NH and cylindrical fuse link form factors.
Phosphor Bronze Contact Clip Stamping
Contact clips are stamped from phosphor bronze strip with controlled spring temper, providing consistent contact pressure on fuse link blades across thousands of insertion/withdrawal cycles. Contact force is verified on a sampling basis using a calibrated insertion force gauge, with minimum values specified per fuse link size (NH00 through NH3).
Fuse Link Element Assembly and Filling
Fuse links are assembled with precision-stamped silver or copper elements spot-welded to end caps. High-purity quartz sand is compacted around the element under controlled vibration, with fill density verified by X-ray inspection of sample links. Each completed fuse link undergoes a continuity check and resistance measurement against the published cold resistance value.
Temperature Rise and Contact Resistance Testing
Fuse holder and link assemblies are tested at rated current in free air. Temperature rise at the fuse link blade-to-holder clip interface and at the holder terminals is measured with thermocouples and verified against IEC 60269-1 limits. Contact resistance is measured using a four-wire micro-ohmmeter and recorded per production lot.
Distributor Stock Holding Programs for Fuse Holders
KRIPAL supports distributor inventory programs with agreed stock levels for standard fuse holder and fuse link models. Shipments are planned based on demand data, with scheduled replenishment to maintain stable supply and consistent fill rates.
Private Label and OEM Branding for Fuse Holders
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 fuse holders and fuse links.
Multi-Region Certification and Compliance Support
CE, UKCA, and IEC 60269-1/2 compliance documentation is provided according to target export markets. Technical documentation files are maintained and updated in line with evolving regulatory requirements for industrial power distribution.
Direct Technical Access to KRIPAL Production Engineers
Your technical team communicates with the engineers who designed and tested your fuse holders and fuse links, not a distributor’s sales engineer reading from a catalog. Application questions including fuse discrimination and I-squared-t coordination receive answers within 24 hours during China business hours.
Frequently Asked Questions
Explore FAQ >gG (general purpose) fuses protect cables against overload and short circuit. aM (motor circuit) fuses provide short-circuit protection only and can withstand motor starting currents up to 6x rated current.
NH sizes: 00 (up to 160A), 0 (up to 160A), 1 (up to 250A), 2 (up to 400A), 3 (up to 630A). Select based on circuit rated current and fuse holder physical size.
Only with a fuse switch-disconnector rated for load-break operation. Standard fuse holders require de-energized circuits before replacement.
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