Fuse tube production splits into three voltage classes: high-voltage, medium-voltage, and low-voltage fuse tubes. All of them must have arc-extinguishing characteristics. This article walks through how a vulcanized fiber fuse tube and a melamine tube are made, so you understand what you are buying.
The Three Voltage Classes and What Each Process Has to Deliver
| Class | Typical service | What the tube must do |
|---|---|---|
| High voltage | Cutouts, drop-out fuses, current limiters | Quench a high-energy arc, resist moisture, carry mechanical load |
| Medium voltage | Distribution and industrial protection | Contain the arc within a compact body, hold electrode clearance |
| Low voltage | Control, electronics, appliances, EV low-voltage circuits | Insulate reliably in a thin wall, resist tracking at temperature |
The tube differs across the three, but the underlying requirement is shared: when the element melts, the liner has to generate quenching gas and let the arc extinguish inside the rated breaking capacity, without the wall deforming or bursting.
Vulcanized Fiber Fuse Tube Production
Tianze high-voltage fuse tubes are made from 100 percent cotton-pulp paper:
- The paper is fully immersed in a zinc chloride solution.
- It is rolled on a tube rolling machine to the required wall thickness.
- The completed tubes are soaked in a desulfurization pool for about 25 days to remove the relevant elements and harden into a blank.
- The blanks are shaped on a line at constant temperature and baked in an oven.
- They are extruded through dies matched to the tube specification.
- They are polished, cut to length, and deburred.
The tube is then shaped to the fuse requirement into a T or K fuse-link tube, or reinforced with epoxy glass fiber winding to become a cutout or drop-out fuse tube.
The Desulfurization Step in Detail
Step three is the one buyers ask about most, and it is also the one that most often gets shortened. After rolling, residual zinc chloride and its reaction products remain inside the wall. Left in place they are conductive and hygroscopic, which is the opposite of what an insulator should be. Soaking the tubes for roughly 25 days leaches those residues out and lets the cellulose fibers finish fusing into a dense, uniform wall.
The step is not just a wash. It is a slow diffusion process working through the full wall thickness, which is why the duration scales with wall build rather than with tube length. Cut it short and the tube still passes a dimensional check and still looks correct, but residue content is high and dielectric performance decays in service rather than failing an incoming test. That failure mode is what makes process records more valuable than a certificate alone.
Melamine Tube Production
Tianze G5/G9 melamine tube is made from electronic-grade glass fiber cloth with melamine resin. The cloth is rolled on a heated tube winder, then heated and cured in an oven and demolded. The finished tube suits new-energy EV fuses, PV solar fuses, and 5G communication fuses. Our G5/G9 melamine tube line article goes deeper into lamination molding, tube rolling, and why inner diameter limits producible length.
The Two Processes Compared
| Step | Vulcanized fiber tube | Melamine tube |
|---|---|---|
| Base material | 100 percent cotton-pulp paper | Electronic-grade glass fiber cloth |
| Binder | None, the fiber fuses into one mass | Melamine resin |
| Forming | Rolled wet, then pressed and extruded | Rolled on a heated winder |
| Key long step | About 25 days desulfurization | Cure and demold |
| Dominant property | Arc quenching and stiffness | Tracking resistance and thin-wall dielectric strength |
| Typical product | Cutout tubes, fuse-link tubes | EV, PV, and communications fuse bodies |
Why the Process Matters
The long desulfurization and curing steps are what give vulcanized fiber its density and arc-quenching behavior. Skipping or shortening them weakens the tube. Choosing a manufacturer that controls the full process is the surest way to get consistent performance, because the properties that decide whether a fuse clears correctly are set deep inside the wall, where no visual inspection reaches. The material choices behind these two routes are covered in our fuse tube material article.
Why Source From a Direct Manufacturer
Tianze Electrical runs the full fuse tube process in-house, with ISO 9001 certification and SGS material testing available, and supplies cutout tubes and fuse-link tubes to global switchgear brands. Because rolling, desulfurization, cure, and machining happen in one plant, we can show you the process records behind a batch rather than only the finished dimensions.
Frequently Asked Questions
Q: Why does vulcanized fiber production take so long?
A: The roughly 25-day desulfurization is what hardens the fiber and removes residual elements; it cannot be rushed.
Q: Can you supply both fiber and melamine tubes?
A: Yes, we produce both, plus epoxy fiberglass composites.
Q: Does a longer desulfurization change the dimensions?
A: The wall settles as residues leave, so finishing and extrusion happen after the soak, not before. That is why the process order cannot be rearranged.
Q: Which process suits a small prototype batch?
A: It depends on the grade rather than the quantity. Tell us the duty and the quantity and we will say which route gives the faster, more economical first article.
Contact sale@fusestube.com for production and lead-time details, or see the fuse tube range.
