HYRT3Z Series DC Fuse Holder – UL94V-0

HYRT3Z DC Fuse Holder for Providing Compact Over-current Protection in PV Systems

The HYRT3Z series DC fuse holder from HUYU Electric provides a dedicated way to protect DC circuits in photovoltaic installations. Designed to accommodate industry-standard 10×38 mm fuses, the fuse holder provides a secure and accessible way to house the overcurrent protection devices being used in the string, combiner box and inverter DC inputs. The solar fuse holder has a maximum voltage of 1000 V DC and can carry currents of up to 32 A, meeting the demanding requirements of modern PV systems. The housing is made of UL94 V-0 flame-retardant thermoplastic, which will not aid in spreading fire in case of a major fault.

The holder is available in both a standard and LED indicator version (HYRT3Z-32L) to provide immediate visual feedback on the status of the fuse for easy maintenance. Pairing the HYRT3Z-1038 DC fuse link with the holder provides an outstanding 33 kA breaking capacity. HUYU Electric is also a factory-direct OEM/ODM supplier for panel builders and solar equipment manufacturers, providing all necessary documentation and private labeling.

Technical Specifications

DC Fuse Link Compatibility – HYRT3Z-1038

The HYRT3Z system is a complete overcurrent protection solution for PV DC circuits. It utilizes a standard size of 10×38 mm fuse and provides 15 different ratings of fuse links from 1A to 32A to match string requirements. These fuses can safely interrupt up to 33 kA of fault current in PV arrays, ensuring complete safety and reliability.

Why Use of Dedicated DC Fuse in PV Systems?

AC fuses and fuse holders are not tested or rated for DC applications. A DC fuse is uniquely designed to extinguish the arc that forms during a fault without the natural zero crossing of AC circuits. The HYRT3Z system includes a ceramic insert and a housing made of UL94V-0 flame-retardant material to safely contain arc energy. The fuse link’s internal filler provides consistent interruption of currents up to 1000 V DC. With the optional LED indicator on the HYRT3Z-32L, users can inspect fuse status visually without technical equipment, streamlining maintenance in large solar arrays.

OEM/ODM Supply – DC Fuse Holders for Solar PV Manufacturers

Buyer’s Guide

How to Select a DC Fuse Holder for Your PV System

Key selection criteria for the HYRT3Z in solar PV string protection.

1. Sizing the Fuse Link Correctly

Select a DC fuse with a current rating that is 1.25 × Isc of the PV string. For example, a string with Isc = 8A should use a 10A fuse. The HYRT3Z-1038 fuse links are available in 15 ratings from 1A to 32A, allowing precise sizing. A fuse rated too high will not protect the string; one rated too low may blow during normal operation.

2. LED Indicator vs. Standard Model

Choose the HYRT3Z-32L DC fuse holder with LED indicator for installations where quick visual maintenance is important — such as large commercial arrays with many strings. The LED illuminates when the fuse is blown, making it easy to identify the faulty string without opening enclosures or testing each fuse individually. The standard HYRT3Z-32 is suitable for cost-sensitive projects where periodic manual inspection is acceptable.

3. Breaking Capacity Verification

Verify that the 33kA DC breaking capacity of the HYRT3Z-1038 fuse exceeds the calculated prospective short-circuit current at the installation point. For most PV string applications, the array’s Isc limits the available fault current, and 33kA provides substantial margin. This ensures the fuse can safely interrupt a short circuit without rupturing.

4. DIN Rail Integration

The HYRT3Z mounts on a standard 35mm DIN rail, making it easy to integrate into combiner boxes and inverter cabinets alongside MCBs, SPDs, and other DIN rail components. The compact width per pole minimizes enclosure space requirements.

Frequently Asked Questions

What is the DC fuse?

A DC fuse is an overcurrent protection device specifically designed for direct current circuits. When the current flowing through it exceeds its rated value, a metal element inside the fuse melts, creating an arc. Unlike an AC fuse, which relies on the alternating current’s natural zero-crossing to extinguish the arc, a DC fuse must force the arc to collapse using an arc-quenching filler (usually silica sand) inside the ceramic tube. The HYRT3Z-1038 is a DC fuse rated for 1000V DC and up to 33kA breaking capacity, purpose-built for photovoltaic string protection.

What is the difference between AC and DC fuses?

The fundamental difference is arc extinguishing. An AC fuse benefits from the current naturally passing through zero 100 or 120 times per second, which helps extinguish the arc when the fuse element melts. A DC fuse has no zero-crossing to assist, so it must contain a special arc-quenching filler and a longer internal element to stretch and cool the arc until it collapses. DC fuses are also marked with a DC voltage rating (e.g., 1000V DC) and a time constant (τ) that indicates the circuit inductance they are tested for. Using an AC fuse on a DC circuit is dangerous — it may fail to interrupt the arc, leading to fire or equipment damage. The HYRT3Z system is a dedicated solar fuse holder and DC fuse combination tested for DC applications.

How to tell if a DC fuse is blown?

There are three common methods. First, visually inspect the fuse tube — most blown DC fuses show a discolored or opaque window, or the internal element will be visibly broken. Second, use a multimeter set to continuity or resistance mode across the fuse terminals; a blown fuse will show an open circuit. Third, if you are using the HYRT3Z-32L DC fuse holder with an LED indicator, a lit LED directly signals that the fuse has blown, providing an immediate visual alert without any tools. For large PV arrays with many strings, the LED indicator model can save significant troubleshooting time.

What is a DC breaker used for?

A DC circuit breaker, such as a DC MCB or DC MCCB, is a resettable overcurrent protection device used to protect DC circuits from overload and short-circuit currents. Unlike a DC fuse, which must be replaced after it operates, a DC breaker can be manually reset after a trip. Both devices serve overcurrent protection, but they are used in different scenarios. Fuses are often preferred for string-level protection in PV systems because they are compact, cost-effective, and provide a high breaking capacity. The HYRT3Z DC fuse holder with a 10×38mm fuse link offers a 33kA breaking capacity in a very small footprint, making it ideal for protecting individual PV strings where space is limited. Breakers are more common for main DC feeders where resettability is valued. In a typical PV system, both may be used together.