Four Fuse Terminal Block Styles, and How to Choose Between Them

Across Phoenix Contact's fuse terminal block range, spotting a blown fuse at a glance relies on the optional LED for three of the four styles.

The fourth, the lever-type, shows you the same thing without it. The lever position changes on its own when a fuse blows.

How a fuse terminal block works

A fuse terminal block builds circuit protection directly into the terminal strip. The fuse sits inline with the wiring, so if the circuit overloads or short-circuits, the fuse-link blows and the terminal block stays exactly where it was. No rewiring, just a fuse to replace.

That part's the same across all four styles, lever-type, screw cap, and two plug-in styles. What's different is how each one shows you a fuse has failed, and that's worth knowing before you pick one out of habit.

Lever-type (HESI): the fault shows itself

The fuse sits behind a flip lever. When a fuse blows, the lever position itself changes, so you can see it's failed without an LED fitted at all. The optional LED is there if you want it, but on this style it's a backup, not the only way to know.

Screw cap (DREHSI): visibility is the trade-off

The fuse sits behind a rotating holder instead. It's a more durable, compact design, but there's no equivalent to the lever's clear visual cue, and visibility is limited unless the optional LED is fitted. If you're choosing this style for its space-saving, tougher build, the LED is what makes fault-finding at a glance possible.

Plug-in (FSI/C and FSI/F): built for fuse format and access, not fault visibility

These two take flat-type fuses and, for the FSI/C, pluggable thermal circuit breakers. Fault visibility on the FSI/C depends on the fuse type fitted, and both take the optional LED. But the real reason to choose either of these isn't fault-finding, it's fuse format flexibility (FSI/C) or staying accessible in a tightly wired panel (FSI/F).

What this means for your next panel

If fast fault-finding matters and you'd rather not add the LED to every terminal block, the lever-type does that job on its own. If space and durability matter more, the screw cap earns its place, just make sure you're getting the LED version if you also want to see a failure at a glance. And if the panel's built around a specific fuse format, the choice comes down to which plug-in style takes that fuse type. If it's tightly wired, FSI/F's front access earns its place regardless of fault visibility.

Base the choice on what the panel needs, not on habit.

As an authorised Phoenix Contact distributor, we can supply all four fuse terminal block styles across the range.