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BS Semiconductor Protection Fuse-Links with Bolted Connections

240/690 Volt Semi-conductor Protection Fuse-Links to IEC 60269-4/BS 88-4 – Type LSC

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BS Semiconductor Protection Fuse-Links with Bolted Connections

240/690 Volt Semi-conductor Protection Fuse-Links to IEC 60269-4/BS 88-4 – Type LSC

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Type LSC Product Information Sheet

Product Description

A comprehensive range of Fuse-Links for the protection of semiconductor devices. The 240 and 690 volt series comply with the performance and dimensional requirements of BS 88: Part 4 and IEC 60269-4.

In addition to the current ratings specified in IEC 60269-4 and BS 88-4, other non-standard current ratings are available.

Indicators

Trip-indicator fuse-links are available for use in parallel with the main fuse-link. Indicator fuse-links can either be attached to the associated fuse-link or mounted separately in panel mounted fuse clips.
A push-on adaptor and micro switch attachment is available for use with the trip indicator to give the facility of remote indication.

Product Description

A comprehensive range of Fuse-Links for the protection of semiconductor devices. The 240 and 690 volt series comply with the performance and dimensional requirements of BS 88: Part 4 and IEC 60269-4.

In addition to the current ratings specified in IEC 60269-4 and BS 88-4, other non-standard current ratings are available.

Indicators

Product Overview

240V & 690V BS Bolted Semiconductor Protection Fuse-Links to IEC 60269-4 / BS 88-4 – Type LSC (aR) Semiconductor Fuse | SCR Fuse | Rectifier Fuse | Ultra Fast Fuse | VFD Drive Protection Fuse | Power Inverter Fuse

Product Introduction

The Lawson Type LSC BS Bolted Type is a comprehensive range of Semiconductor Protection Fuse links engineered to provide ultra-fast, precise overcurrent protection for semiconductor devices including thyristors, SCRs, diodes, rectifier bridges, IGBTs, and power modules. Available in both 240V Semiconductor Fuse and 690V Semiconductor Fuse ratings, with current ratings from 10A to 900A, the Type LSC is one of the most complete BS Bolted Type Semiconductor Fuse ranges available from a UK manufacturer.

Whether you need a Rectifier Protection Fuse for an industrial DC power supply, an Ultra Fast Fuse for a thyristor stack in a motor drive, a VFD Drive Protection Fuse for a variable frequency inverter, or a Power Inverter Fuse in a renewable energy system, the Lawson Type LSC delivers the fast-acting, high-energy semiconductor fuse-link performance your application demands.

Fully compliant with IEC 60269-4 — the international standard dedicated to Semiconductor Fuse Links — and its British Standard equivalent BS 88-4, the Type LSC is the trusted choice of power electronics engineers, panel builders, and OEM drive manufacturers across the UK and internationally. Non-standard current ratings beyond those specified in IEC 60269-4 and BS 88-4 are also available to meet specific application requirements.

Key Features

Semiconductor Protection Fuse to IEC 60269-4 / BS 88-4 — purpose-designed for semiconductor device protection
Available as 240V Semiconductor Fuse (10A–900A) and 690V Semiconductor Fuse (10A–710A)
Ultra Fast Fuse operating characteristics — activates before semiconductor I²t withstand is exceeded
SCR Fuse and thyristor protection — matched I²t and voltage characteristics for SCR stacks
Rectifier Fuse and Rectifier Protection Fuse — for AC/DC converter and bridge rectifier protection
VFD Drive Protection Fuse — protects variable frequency drive inverter and rectifier stages
Fast Acting Fuse design — operates significantly faster than standard gG industrial fuses
EPFC (Electronic Power and Frequency Conversion) Protection Fuse — for converters, inverters, and UPS systems
Power Inverter Fuse — suitable for solar inverters, grid-tie systems, and industrial DC-AC converters
BS Bolted Type Semiconductor Fuse — secure, low-resistance bolted connections for high-current applications
Fuse in Inverter applications supported across all voltage and current ranges
Trip-indicator fuse-links available — for visual and remote fault indication
Push-on adaptor and microswitch attachment for remote panel alarm signalling
Non-standard current ratings available on request

Trip Indicator Fuse-Links

A critical feature of the Type LSC Semiconductor Protection Fuse range is the availability of trip-indicator fuse-links — essential in power electronics panels where a blown Fast Acting Fuse may not be immediately visible from outside the enclosure.

Trip indicators are available in two mounting options:

Attached directly to the associated fuse-link — compact, integrated indication right at the fuse location
Mounted separately in panel-mounted fuse clips — for remote visual indication at a convenient panel location

A push-on adaptor and microswitch attachment is also available, enabling the trip indicator to trigger a remote alarm output or control signal — supporting automated fault detection in drives, UPS systems, and power converters.

Applications

The Lawson Type LSC (aR)Semiconductor Fuse Links range is specified across a wide range of power electronics and industrial applications:

Variable Frequency Drives (VFDs) — VFD Drive Protection Fuse for rectifier and inverter bridge semiconductors
AC and DC motor drives — SCR Fuse and thyristor converter protection in soft starters and DC drives
Power inverters — Power Inverter Fuse and Fuse in Inverter applications for industrial and renewable energy systems
Rectifiers and DC power supplies — Rectifier Fuse and Rectifier Protection Fuse for AC/DC converter bridges
UPS and standby power systems — EPFC Protection Fuse for UPS rectifier and inverter stages
Solar and wind energy inverters — 240V and 690V Semiconductor Fuse for grid-tie and off-grid converter protection
Railway and traction power electronics — Ultra Fast Fuse for rolling stock converter and traction drive protection
Industrial electrochemical processes — high-current Rectifier Protection Fuse for plating, electrolysis, and refining equipment
HVDC transmission systems — 690V Semiconductor Fuse for converter station thyristor valve protection

Why Choose Lawson Type LSC?

Semiconductor devices are among the most expensive and time-critical components in any power electronics system. When a fault occurs, the difference between a protected and a destroyed thyristor, IGBT, or rectifier diode is measured in microseconds. Only a purpose-engineered Ultra Fast Fuse with the correct I²t rating, voltage rating, and arc energy characteristics can reliably interrupt fault current before device failure occurs.

The Lawson Type LSC Semiconductor Protection Fuse range is specifically designed and tested to these demanding requirements. With a current range spanning 10A to 900A across both 240V Semiconductor Fuse and 690V Semiconductor Fuse series, full IEC 60269-4 / BS 88-4 compliance, non-standard ratings on request, and a comprehensive trip indication and remote signalling system, the Type LSC is a complete BS Bolted Type Semiconductor Fuse solution backed by Lawson’s decades of specialist fuse engineering.

All products are manufactured under an ISO 9001 accredited quality management system with test facilities independently accredited to ISO/IEC 17025 — ensuring consistent, reliable performance in every SCR Fuse, Rectifier Fuse, and VFD Drive Protection Fuse that leaves the factory.

Principal Ratings 240 Volt

Principal Ratings*
Vol age Rating a.c. Volt	urrent Rating Amps	List Reference	Dimensional Reference
240	10	LSCA10	Figure 1
240	12	LSCA12	Figure 1
240	16	LSCA16	Figure 1
240	20	LSCA20	Figure 1
240	25	LSCA25	Figure 1
240	30	LSCA30	Figure 1
240	32	LSCA32	Figure 1
240	35	LSCA35	Figure 1
240	40	LSCA40	Figure 1
240	50	LSCA50	Figure 1
240	60	LSCA60	Figure 1
240	63	LSCA63	Figure 1
240	70	LSCA70	Figure 1
240	75	LSCA75	Figure 1
240	80	LSCA80	Figure 1
240	85	LSCA85	Figure 1
240	100	LSCA100	Figure 1
240	125	LSA125	Figure 1
240	160	LSA160	Figure 1
240	180	LSA180	Figure 1

240	125	LSCA125	Figure 2
240	140	LSCA140	Figure 2
240	150	LSCA150	Figure 2
240	160	LSCA160	Figure 2
240	175	LSCA175	Figure 2
240	180	LSCA180	Figure 2
240	200	LSCA200	Figure 2
240	225	LSCA225	Figure 2
240	250	LSCA250	Figure 2
240	260	LSCA260	Figure 2
240	300	LSCA300	Figure 2
240	315	LSCA315	Figure 2
240	350	LSA350	Figure 2
240	355	LSA355	Figure 2
240	400	LSA400	Figure 2
240	450	LSA450	Figure 2

240	300	LSAD300	Figure 3
240	315	LSAD315	Figure 3
240	325	LSCAD325	Figure 3
240	350	LSCAD350	Figure 3
240	355	LSCAD400	Figure 3
240	400	LSCAD450	Figure 3
240	450	LSCAD500	Figure 3
240	500	LSCAD550	Figure 3
240	550	LSCAD600	Figure 3
240	600	LSCAD630	Figure 3
240	630	LSCAD333	Figure 3
240	710	LSAD710	Figure 3
240	800	LSAD800	Figure 3
240	900	LSAD900	Figure 3

Principal Ratings 690 Volt

Principal Ratings*
Voltage Rating a.c. Volt	Current Rating Amps	List Reference	Dimensional Reference
690	10	LSCB10	Figure 1
690	16	LSCB16	Figure 1
690	20	LSCB20	Figure 1
690	25	LSCB25	Figure 1
690	30	LSCB30	Figure 1
690	32	LSCB32	Figure 1
690	35	LSCB35	Figure 1
690	40	LSCB40	Figure 1
690	45	LSCB45	Figure 1
690	50	LSCB50	Figure 1
690	55	LSCB55	Figure 1
690	63	LSCB63	Figure 1
690	70	LSCB70	Figure 1
690	71	LSCB71	Figure 1
690	75	LSCB75	Figure 1
690	80	LSCB80	Figure 1
690	90	LSCB90	Figure 1
690	100	LSCB100	Figure 1

690	65	LSCBT65	Figure 2
690	75	LSCBT75	Figure 2
690	85	LSCBT85	Figure 2
690	90	LSCBT90	Figure 2
690	100	LSCBT100	Figure 2
690	110	LSCBT110	Figure 2
690	120	LSCBT120	Figure 2
690	125	LSCBT125	Figure 2
690	140	LSCBT140	Figure 2
690	150	LSCBT150	Figure 2
690	160	LSCBT160	Figure 2
690	180	LSCBT180	Figure 2
690	200	LSCBT200	Figure 2

690	160	LSCB160	Figure 3
690	170	LSCB170	Figure 3
690	180	LSCB180	Figure 3
690	190	LSCB190	Figure 3
690	200	LSCB200	Figure 3
690	225	LSCB225	Figure 3
690	250	LSCB250	Figure 3
690	280	LSCB280	Figure 3
690	315	LSCB315	Figure 3
690	350	LSCB350	Figure 3
690	355	LSCB355	Figure 3

690	175	LSCBD175	Figure 4
690	180	LSCBD180	Figure 4
690	200	LSCBD200	Figure 4
690	225	LSCBD225	Figure 4
690	235	LSCBD235	Figure 4
690	280	LSCBD280	Figure 4
690	300	LSCBD300	Figure 4
690	315	LSCBD315	Figure 4
690	325	LSCBD325	Figure 4
690	350	LSCBD350	Figure 4
690	355	LSCBD355	Figure 4
690	400	LSCBD400	Figure 4
690	450	LSCBD450	Figure 4
690	500	LSCBD500	Figure 4
690	550	LSCBD550	Figure 4
690	560	LSCBD560	Figure 4
690	630	LSCBD630	Figure 4
690	710	LSBD710	Figure 4

Dimensions in Millimetres

Voltage Rating (V)	Current Rating (A)	Fig No.	Dimensions in millimetres
			A max.	B max.	D max.	E nom.	F max.	G nom.	H nom.	J min.	K max.
240	10-100	1	29.2	17.7	58.4	12.7	2.5	41.8	6.4	7.9	19.3
240	125-315	1	32.6	38.2	85.0	25.4	3.3	59.0	10.3	13.0	41.5
240	350-630	3	32.6	38.2	85.0	25.4	6.4	59.0	10.3	13.0	83.0
690	10-100	1	50.6	17.7	79.8	12.7	2.5	63.5	6.4	7.9	19.3
690	125-200	2	50.6	37.0	95.0	32.0	1.6	70.0	8.7	10.3	19.9
690	200-355	1	60.0	38.2	114.0	25.4	3.3	85.0	10.3	13.0	41.5
690	350-630	3	60.0	38.2	114.0	25.4	6.4	85.0	10.3	13.0	83.0

Frequently Asked Questions – Semiconductor Fuse / SCR Fuse / Rectifier Fuse / Ultra Fast Fuse

Q1. What is a Semiconductor Fuse?

A Semiconductor Fuse — also called a Semiconductor Protection Fuse or Semiconductor Fuse Link — is a specialised high-speed fuse-link designed to protect semiconductor devices such as thyristors, SCRs, diodes, IGBTs, and rectifier bridges from destruction caused by overcurrent faults. Unlike standard gG industrial fuses, a Semiconductor Fuse operates at extremely high speed to interrupt fault current before the I²t energy absorbed by the semiconductor device exceeds its rated withstand value. The Lawson Type LSC is a BS Bolted Type Semiconductor Fuse available in 240V and 690V series with current ratings from 10A to 900A.

Q2. What is the difference between a Semiconductor Fuse and a standard industrial fuse?

A standard industrial fuse (such as a gG type) is designed for general overload and short-circuit protection of cables and equipment, and operates on a relatively slow time-current characteristic. A Semiconductor Fuse — such as an SCR Fuse, Rectifier Fuse, or Ultra Fast Fuse — is designed to operate significantly faster, with a much lower I²t value (let-through energy), to interrupt fault current within microseconds. This speed is essential because semiconductor devices, unlike cables or motors, can be destroyed almost instantaneously by even brief overcurrent events.

Q3. What is a SCR Fuse and where is it used?

An SCR Fuse is a Semiconductor Protection Fuse specifically rated and characterised for the protection of Silicon Controlled Rectifiers (SCRs) — also known as thyristors. SCR Fuses are used in thyristor-based power converters, DC motor drives, soft starters, and industrial rectifiers where SCR devices must be protected against short-circuit overcurrents that could destroy the device faster than a standard fuse could respond. The Lawson Type LSC SCR Fuse range covers both 240V and 690V applications.

Q4. What is a Rectifier Fuse and a Rectifier Protection Fuse?

A Rectifier Fuse (or Rectifier Protection Fuse) is a fast-acting semiconductor fuse-link used to protect individual diodes or complete rectifier bridge assemblies in AC/DC power conversion equipment. Rectifier diodes, like thyristors, have a limited I²t withstand capability and can be destroyed in milliseconds by fault currents that a standard industrial fuse would take much longer to clear. The Lawson Type LSC provides Rectifier Fuse protection across a wide range of voltage and current ratings for both single-phase and three-phase rectifier applications.

Q5. What is a VFD Drive Protection Fuse?

A VFD Drive Protection Fuse is a Semiconductor Fuse specifically applied to protect the power semiconductor devices — typically IGBTs or thyristors — within a Variable Frequency Drive (VFD), also called a Variable Speed Drive (VSD) or inverter drive. These drives contain rectifier stages that convert AC to DC and inverter stages that convert DC back to variable-frequency AC. Both stages contain semiconductors that require Ultra Fast Fuse protection. The Lawson Type LSC is widely used as a VFD Drive Protection Fuse in both the incoming rectifier bridge and the DC bus of industrial drive systems.

Q6. What is an EPFC Protection Fuse?

EPFC stands for Electronic Power and Frequency Conversion — a broad category that encompasses AC/DC converters, DC/AC inverters, frequency converters, UPS systems, and similar power conversion equipment. An EPFC Protection Fuse is a Semiconductor Fuse applied to protect the semiconductor devices within this equipment. The Lawson Type LSC Fast Acting Fuse and Ultra Fast Fuse range covers EPFC protection applications across both 240V and 690V supply voltages.

Q7. What is a Power Inverter Fuse and a Fuse in Inverter?

A Power Inverter Fuse (also referred to as a Fuse in Inverter) is a Semiconductor Fuse used to protect the semiconductor switching devices — typically IGBTs, MOSFETs, or thyristors — within a power inverter. Inverters convert DC power to AC power and are found in solar PV systems, wind turbines, UPS units, motor drives, and industrial power supplies. Because the switching semiconductors inside an inverter can fail catastrophically within microseconds of a fault, an Ultra Fast Fuse with correctly matched I²t characteristics is essential for reliable protection.

Q8. What is the difference between a 240V Semiconductor Fuse and a 690V Semiconductor Fuse?

The 240V Semiconductor Fuse series (Type LSC — LSCA/LSA/LSCAD/LSAD references) is designed for use in 230/240V a.c. single-phase or lower-voltage power electronics applications, while the 690V Semiconductor Fuse series (LSCB/LSCBT/LSCBD/LSBD references) is designed for use in 400V, 415V, 500V, or 690V a.c. three-phase power electronics systems. Both series comply with IEC 60269-4 / BS 88-4 but have different physical dimensions and arc energy characteristics matched to their respective voltage levels. Selecting the correct voltage-rated Semiconductor Fuse is critical to ensuring safe and reliable operation.

Q9. What trip indication options are available with the Type LSC Semiconductor Protection Fuse?

The Type LSC range includes trip-indicator fuse-links that can be used in parallel with the main Semiconductor Fuse to provide a clear visual indication when the fuse has operated. Indicators can be attached directly to the associated fuse-link or mounted separately in panel-mounted fuse clips. A push-on adaptor and microswitch attachment is also available, enabling the trip indicator to activate a remote alarm or control signal — supporting automated fault detection in VFD drives, UPS systems, rectifiers, and power converters.

Q10. Are non-standard current ratings available for the Type LSC Semiconductor Fuse?

Yes. In addition to the standard current ratings specified in IEC 60269-4 and BS 88-4, Lawson Fuses can supply non-standard current ratings within both the 240V Semiconductor Fuse and 690V Semiconductor Fuse series to meet specific application requirements. Contact the Lawson Fuses sales team or your authorised sales partner to discuss custom rating requirements for your semiconductor protection application.

Q11. How do I select the correct Semiconductor Fuse for my application?

Selecting the correct Semiconductor Protection Fuse requires matching several key parameters to your semiconductor device and circuit: rated voltage (240V or 690V), current rating, I²t let-through energy (must be less than the semiconductor device’s I²t withstand), peak arc voltage (must not exceed device voltage rating), and physical dimensions and mounting configuration. For guidance on selecting the correct SCR Fuse, Rectifier Fuse, Ultra Fast Fuse, or VFD Drive Protection Fuse for your application, download the Type LSC Product Information Sheet or contact the Lawson Fuses technical sales team directly.