RT14 – AC Fuse 2A-63A 380V – Cylindrical Cap Fuse

RT14 AC Fuse – Small Sized Cylindrical Protection For Industrial Circuits

HUYU Electric’s RT14 series AC fuses protect against overcurrents and short circuits on industrial electrical systems with an input voltage of 380V AC at 50 Hz. The cylindrical AC fuse is manufactured in three standard sizes (10×38mm, 14×51mm, and 22×58mm) with ratings of 2A to 63A and is widely used in motor control centres, power distribution panels, and industrial automation equipment. Additionally, the striker mechanism, which is included in the 14×51mm and 22×58mm, can assist in providing additional protection to electric motors from phase failure when paired with the appropriate fuse-disconnectors.

The RT14 series AC cylindrical fuse provides consistent, repeatable performance by complying with the requirements of GB/T13539.1 and GB/T13539.2. The small size of these fuses allows high-density installations in fuse holders and switch-disconnectors, while the nickel-plated copper end caps provide low contact resistance. HUYU Electric offers OEM/ODM factory-direct services to equipment manufacturers and electrical distributors, which include custom branding and all necessary certification documents.

Technical Specifications

The RT14 AC Fuse series provides the most commonly required fuses for industrial applications. The 10×38 millimeter sizes handle circuits that have current ratings of less than or equal to twenty amps, while the 14×51 millimeter adds circuits with current ratings of less than or equal to thirty-two amps. An optional striker can also be used in conjunction with the 14×51 unit for protection of motors. The 22×58 millimeter size will handle main feeder circuits with current ratings of less than or equal to sixty-three amps. By providing these graduated sizes, this allows specifiers to select the most space and cost-efficient cylindrical type fuses to be used in each of the circuits within the distribution panel.

Striker for Phase Failure Protection

A significant feature of the RT14-32 and RT14-63 AC fuses is the striker mechanism which is an option. The striker is activated when the fuse element melts from an overload or short circuit, and the striker extends from the end cap of the fuse, providing a mechanical signal that can close a micro switch located in the compatible fuse disconnector. This signal can be used to disconnect the motor starter circuit, thus providing phase failure protection — a very significant and important safety function for three-phase motors, as single-phasing can lead to winding damage. A motor protection fuse that provides the same functionality as the above is highly desirable for use with either motor control centers or pumping panels, thus eliminating the need for individual phase monitoring relays.

OEM/ODM Supply – Cylindrical AC Fuses for Industrial Equipment

Buyer’s Guide

How to Select an AC Fuse for Industrial Motor and Distribution Circuits

Key selection criteria for the RT14 in motor protection and power distribution applications.

1. Choosing the Right AC Fuse Size

Select the fuse size based on the available space in the fuse holder or disconnect switch. The 10×38mm AC fuse suits compact control circuits up to 20A. The 14×51mm format handles up to 32A and offers the striker option for motor protection. The 22×58mm size covers feeder circuits up to 63A. Always match the fuse size to the holder — they are not interchangeable across sizes.

2. Sizing the Current Rating

For general distribution circuits, the AC fuse rating should match the circuit’s continuous current. For motor circuits, the fuse must withstand the motor’s starting inrush. A typical guideline is to select a fuse rated at 125%–175% of the motor full-load current. The RT14’s wide current range from 2A to 63A allows precise matching to the load.

3. Striker or Non-Striker?

Choose the striker version for motor circuits where phase failure protection is required. When a fuse blows due to an overload or single-phasing condition, the striker extends and can trigger a micro-switch in the fuse-disconnector to shut down the motor starter, preventing winding damage. For non-motor applications, the non-striker version is sufficient and slightly more economical.

4. Coordination with Upstream Protection

The RT14 cylindrical AC fuse should be coordinated with upstream circuit breakers or fuses to ensure selective tripping. The fuse’s I²t characteristics allow precise coordination — a smaller fuse downstream will clear a fault before a larger upstream device operates. Consult the fuse manufacturer’s time-current curves for detailed coordination analysis.

Frequently Asked Questions

What is a fuse cap?

A fuse cap refers to the metal end caps of a cylindrical fuse, which serve as the electrical connection points between the fuse element inside and the external circuit. In an AC fuse like the RT14, these nickel-plated copper caps are crimped onto the ceramic tube and provide a standardized contact surface for fuse holders and clips. The term “cap fuse” distinguishes this cylindrical form factor from blade-type or bolt-down fuses. The RT14 series uses precision-formed end caps that ensure low contact resistance and reliable current transfer in industrial applications.

Do I need a fuse between capacitor and amp?

In audio systems, a fuse between a power capacitor and an amplifier is recommended as a safety measure. The capacitor stores energy and can deliver very high currents during a short circuit. While the RT14 is an industrial AC fuse rated for 380V, not a 12V automotive fuse, the protection principle is the same: the fuse protects the wiring and connected equipment from overcurrent. For automotive or low-voltage DC applications, use a DC-rated fuse or circuit breaker appropriate for the system voltage and current. The RT14 series is designed for industrial AC power distribution and motor protection, not consumer audio.

What are the three types of fuses?

Fuses are commonly categorized by their form factor and application. Three broad types are: (1) Cylindrical AC fuses (such as the RT14), which are tubular with metal end caps, widely used in industrial control and power distribution; (2) Blade-type fuses, which have flat metal prongs, common in automotive and low-voltage applications; and (3) Bolt-down fuses, which have terminal holes for screw or bolt connection, used in high-current applications like battery banks and DC distribution. The RT14 series is an industrial AC cylindrical fuse designed for 380V circuits up to 63A.

What are two types of fuses?

At a high level, fuses can be divided into two categories: AC fuses and DC fuses. An AC fuse, like the RT14 cylindrical fuse, is designed for alternating current circuits where the current naturally passes through zero 100 or 120 times per second, assisting arc extinction. A DC fuse must extinguish a continuous arc without zero-crossing, requiring different internal construction with arc-quenching filler. The RT14 is specifically an AC fuse rated for 380V/50Hz, suitable for motor protection and power distribution in industrial environments. For DC applications such as photovoltaic or battery storage, DC-rated fuses with appropriate voltage and breaking capacity specifications must be used instead.