Mersen GDG Series Time-Delay G...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$551.43
Mersen GDG Series Time-Delay Glass Fuse, 250VAC, 5x20mm

Mersen GDG Series Time-Delay Glass Fuse, 250VAC, 5x20mm

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Model: GDG4

In Stock (leaves warehouse same day if ordered before 3pm ET)

$551.43
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Mersen GDG Series Time-Delay Glass Fuse, 250VAC, 5x20mm

The Mersen GDG Series is a line of time-delay glass fuses rated 250VAC, built in the compact, industry-standard 5x20mm form factor with ferrule terminals for clip-mount installation. This supplemental class fuse combines a glass body for visual status indication with a time-delay speed characteristic that rides out momentary inrush currents while still tripping reliably on sustained overloads or faults, making it a dependable choice for protecting sensitive circuits and equipment in professional electrical installations such as control panels, instrumentation systems, and small motor and lighting circuits.

Key Features

  • 5x20mm Fuse Size: Compact, industry-standard dimensions with a product length of approximately 0.79 in, fitting standard miniature fuse holders and clips.
  • 250VAC Voltage Rating: Suitable for standard AC voltage applications with reliable, consistent performance characteristics.
  • Time-Delay Speed Characteristic: Tolerates brief inrush or startup surges while still protecting against sustained overcurrent conditions.
  • Glass Body Insulating Material: Provides visual indication of fuse status along with reliable insulation properties for safe operation.
  • Ferrule Connection Terminal, Clip Mounting Method: Ensures secure electrical connections and simple installation in compatible fuse clips and holders.
  • Supplemental Fuse Class: Purpose-built for equipment-level overcurrent protection in control and instrumentation circuits rather than branch-circuit service.
  • Lightweight, Compact Design: Approximately 0.01 lb per fuse for easy handling, shipping, and stocking in maintenance inventories.

Certifications & Compliance

  • RoHS Compliant

Technical Specifications

  • Ac Or Dc: AC
  • Rohs Compliant: Yes

Typical Applications

  • Electronic Equipment Protection
  • Control Panel Circuits
  • Instrumentation Systems
  • Small Motor Protection
  • Lighting Circuit Protection
  • Power Supply Applications
  • Industrial Control Systems

Why Mersen?

Mersen builds the GDG Series with glass body construction for at-a-glance status indication, a secure ferrule terminal and clip-mount design, and RoHS compliance for environmentally responsible installations. The supplemental class rating and time-delay speed characteristic give electrical professionals a dependable, code-aware option for protecting sensitive equipment, instrumentation, and control circuits where precise, repeatable overcurrent protection is essential.

Manufacturer Resources

Product Specs

Product Type:
Fuse
Product Material:
Glass
Voltage Rating:
250VAC
Connection Type:
Ferrule
Standards:
RoHS Compliant
Department:
Electrical
Product Group:
Wiring Devices

Mersen GDG4 – Frequently Asked Questions

1) Will a Mersen GDG fuse fit a 5x20mm fuse holder?
That is exactly the size it is built in. The GDG Series is a 5x20mm glass body fuse with ferrule ends, roughly 0.79 in long, and it drops into standard miniature 5x20mm clips and holders. If your holder is the shorter 5x20's cousin, the 1/4 x 1-1/4 in (6.3x32mm) size, the GDG will not seat properly and you need a different fuse.
2) Time-delay or fast-acting fuse for a control transformer or small motor?
Time delay, which is what the GDG gives you. It rides through the inrush of a transformer, power supply, or motor start and still opens on a sustained overload or fault. A fast-acting fuse in that spot nuisance-trips on startup. Where you do want fast-acting, for semiconductors or instrumentation with no inrush, a midget fast-acting type like the Littelfuse BLF Series (250V) is the other side of that choice.
3) I need branch-circuit protection instead of supplemental - what should I use instead of the Mersen GDG?
Step up to a Class CC fuse such as the Littelfuse CCMR040, a CCMR Series Class CC time-delay fuse rated 40A. The Mersen GDG Series is a supplemental class fuse built for equipment-level overcurrent protection in control and instrumentation circuits rather than branch-circuit service, so where the drawing or the NEC calls for a branch-circuit listed fuse, a Class CC device is the correct family. The CCMR also shares the time-delay characteristic, so it will still ride through motor starting inrush.
4) What amperages does the Mersen GDG time-delay glass fuse come in?
Five ratings: 0.315A (GDG315/1000), 1A (GDG1), 2A (GDG2), 4A (GDG4) and 5A (GDG5). Order by the MPN, since the ampere rating is what separates them; voltage, body, and speed are the same across all of them at 250VAC.
5) Is the Mersen GDG rated for DC circuits?
The rating is 250VAC and the fuse is specified as AC. Don't apply it on a DC bus based on that number, since DC interrupting behavior is not part of this rating.
6) Is a Littelfuse AGA or AGU glass fuse a direct swap for a Mersen GDG?
Not a drop-in assumption. The AGA and AGU are Littelfuse glass tube fuses but they are different series in different body sizes than the 5x20mm GDG, so the ferrule spacing in your clip decides it. Match the physical size stamped on the fuse you pulled out, then the amp and voltage rating, before substituting.
7) For a metering circuit, should I order the Mersen GDG or the Square D PowerLogic fuse pack?
Match the meter. The Square D PowerLogic Energy Meter Fuse Pack is a factory set of three 0.5A 600V fuses supplied specifically for PowerLogic energy meter voltage inputs, so if you are fusing the PT leads on that meter, the matched pack is the intended part. The Mersen GDG Series is a 250VAC supplemental time-delay glass fuse in 5x20mm, which suits control panel, instrumentation and small motor or lighting circuits at 250V and below. The 600V rating on the PowerLogic pack is the deciding spec on metering potential circuits above 250V.
8) My control panel has nuisance blowing on power-up - is there a fuse better suited than a fast-acting one?
Yes, move to a time-delay element. The Mersen GDG Series carries a time-delay speed characteristic that rides out momentary inrush currents while still tripping on sustained overloads or faults, which is what you want on transformer, power supply and small motor circuits. A fast-acting midget such as the Littelfuse BLF Series clears quickly by design and is the better fit on purely resistive or semiconductor-side loads. Confirm the holder format first: the GDG is 5x20mm with ferrule terminals, while the BLF uses a laminated midget tube.
9) Can I tell if a GDG fuse is blown without pulling it out?
Usually yes. The body is glass, so you can see the element and a blown fuse typically shows a broken or clouded element through the tube. That is the practical reason maintenance crews stock glass bodies over ceramic in control cabinets.
10) Does the Mersen GDG fuse meet RoHS for our facility spec?
Yes, the GDG Series is RoHS compliant, which covers the usual restricted-substance line item on institutional and OEM panel specs.
11) Which fuse should I standardize on across a facility if I need RoHS compliance?
The Mersen GDG Series is RoHS compliant and spans 0.315A, 1A, 2A, 4A and 5A in one 5x20mm glass body format, so a single clip style and holder covers the range and the stocked SKUs differ only by amperage. That makes it a practical standard for control panel and instrumentation fusing across a portfolio. For branch-circuit positions the same standard will not apply, since the GDG is a supplemental class fuse.
How fast can I get the Mersen GDG4 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Mersen GDG4 come with a warranty?
Absolutely. The Mersen GDG4 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Mersen GDG4?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
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