Q1. What is a gG Fuse?
A gG Fuse is a general purpose fuse-link conforming to the utilisation category “gG” as defined by IEC 60269 — the international standard for low-voltage fuse-links. The “g” indicates full-range breaking capability, meaning the fuse can interrupt both overload currents and short-circuit currents across its entire current range. The “G” denotes general purpose protection for cables and conductors. The Lawson Type MD is a cylindrical gG Fuse rated at 400/415V a.c. with an 80kA breaking capacity, available in current ratings from 2A to 32A for three-phase sub-circuit protection.
Q2. What is a General Purpose Fuse and what does it protect?
A General Purpose Fuse is a fuse-link designed to protect electrical conductors, cables, and circuits from both overload currents (currents moderately above the rated current sustained over time) and short-circuit currents (high magnitude fault currents). The Lawson Type MD General Purpose Fuse is specifically designed for use in three-phase sub-circuits in industrial and commercial installations, protecting circuit conductors from thermal damage under overload conditions and safely interrupting up to 80kA of fault current under short-circuit conditions.
Q3. What is an Electrical Cartridge Fuse?
An Electrical Cartridge Fuse is a type of fuse-link enclosed in a cylindrical cartridge body — typically ceramic or glass — with metal end caps that make contact with the fuse holder. The fuse element is enclosed within the body, which is filled with arc-quenching material (typically quartz sand) to safely extinguish the arc when the fuse operates. The Lawson Type MD is a ceramic-body Electrical Cartridge Fuse measuring 29mm in length and 12.7mm in diameter — a compact format that fits in a wide range of panel-mount and DIN-rail fuse holders.
Q4. What is the difference between a gG Fuse and a gM Fuse?
A gG Fuse provides full-range general purpose protection for both overloads and short circuits — the standard choice for cable and conductor protection in most industrial and commercial applications. A gM Fuse has a dual rating, with a higher motor circuit current rating alongside the base fuse rating, making it more tolerant of motor starting current surges. The Lawson Type MD is a gG Fuse and is appropriate for general sub-circuit protection where motor starting inrush is not a design factor. Where motor protection is the primary requirement, the Lawson industrial gM-rated fuse-link range should be considered.
Q5. What voltage and breaking capacity does the Lawson Type MD General Purpose Fuse have?
The Type MD gG Fuse is rated at 400/415V a.c. for three-phase supply applications, with a breaking capacity of 80kA — well above the breaking capacity of many competing cylindrical Electrical Cartridge Fuse products in this size class. This high breaking capacity means the Type MD can be safely used in circuits close to supply transformers and in industrial installations where prospective fault levels are elevated.
Q6. What standards does the Type MD General Purpose Fuse comply with?
The Lawson Type MD General Purpose Fuse is primarily compliant with IEC 60269-1 and BS 88-1 — the international and British Standards for general purpose low-voltage fuse-links. Notably, it also meets the performance requirements of the more stringent IEC 60269-2 and BS 88-2 industrial fuse standard, and has been independently ASTA Certified to the ASTA 20 Scheme. Lawson’s manufacturing operations are accredited to ISO 9001, with test facilities accredited to ISO/IEC 17025.
Q7. What current ratings are available for the Type MD Electrical Cartridge Fuse?
The Type MD gG Fuse range is available in nine current ratings: 2A, 4A, 6A, 8A, 10A, 16A, 20A, 25A, and 32A. All ratings share identical physical dimensions of 29mm length x 12.7mm diameter, simplifying fuse holder selection and allowing a single holder type to be used across the entire current range — reducing both design complexity and spare parts stock.
Q8. What are the dimensions of the Type MD Electrical Cartridge Fuse?
The Type MD Electrical Cartridge Fuse measures 29mm (1⅛ inch) in length and 12.7mm (½ inch) in diameter across all current ratings from 2A to 32A. This compact and consistent cylindrical format is designed for use in panel-mount and DIN-rail fuse holders compatible with this size class.
Q9. Can the Type MD General Purpose Fuse be used in high fault level industrial installations?
Yes. The Type MD gG Fuse has an 80kA breaking capacity at 415V a.c., making it specifically suitable for circuits with high prospective fault levels — including industrial installations in close proximity to supply transformers. The additional compliance with IEC 60269-2 / BS 88-2 requirements further confirms its suitability for demanding industrial protection applications.
Q10. How does the Type MD compare to the Type CDS compact dimension fuse range?
The Type MD General Purpose Fuse is a cylindrical Electrical Cartridge Fuse (29mm x 12.7mm) designed for three-phase sub-circuit protection in industrial panels and distribution boards. The Type CDS compact dimension fuse range (NS, SS, MES types) is a clip-fit fuse for use in Clipfit fuse holders or distribution fusegear, covering a broader current range up to 63A. Both are gG type fuses complying with IEC 60269 standards, but they are designed for different holder systems and installation contexts. Choose Type MD for cylindrical holder applications and Type CDS for Clipfit fuse holder panel assemblies.
Q11. How do I order the Lawson Type MD gG Fuse or General Purpose Fuse?
The Type MD General Purpose Fuse, gG Fuse, and Electrical Cartridge Fuse range is available through the Lawson Fuses sales team and their network of authorised sales partners and electrical wholesalers across the UK. Contact Lawson Fuses directly for trade pricing, availability by current rating, and technical support for your industrial or commercial installation.
