StarTech FAN4SPLIT12 4-Pin PWM Fan Splitter Cable

Overview

The StarTech FAN4SPLIT12 is a 12-inch, 4-pin PWM fan splitter cable that converts a single motherboard or controller fan header into two independent outputs — letting you run two fans from one header without adding a controller card or sacrificing PWM speed regulation. At 0.4 oz and just 0.6 inches wide, it disappears into a chassis wire bundle without contributing to cable management headaches. If you're managing thermal performance in a surveillance NVR enclosure, rack-mount server, or edge computing chassis where fan headers are scarce, this cable solves the header-count problem cleanly and without firmware changes.

The FAN4SPLIT12 ships with a lifetime manufacturer warranty, which is the correct expectation for a passive copper cable — there are no active components to fail.

Key Features

• 1-to-2 PWM Fan Header Split: One LP4 4-pin PWM input feeds two LP4 4-pin PWM outputs. Both connected fans receive the same PWM duty-cycle signal from the source header, so your motherboard or fan controller continues to govern speed automatically — you're not locking fans to a fixed voltage the way a 3-pin passive splitter would.
• 12-Inch Cable Length: At exactly 12 inches (roughly 30 cm), the FAN4SPLIT12 reaches comfortably across a standard mid-tower or 2U/4U rack chassis without excess slack bunching near the header. Shorter splitters force awkward fan repositioning; longer ones create drag in airflow paths. This length hits the practical middle ground for most NVR and server builds.
• 26 AWG Wire Gauge: 26 AWG is the standard gauge for system fan wiring. It handles the current draw of typical 4-pin PWM chassis fans without voltage drop that would skew speed readings, while keeping the cable flexible enough to route through tight chassis channels.
• LP4 4-Pin PWM Connectors on Both Ends: The male LP4 connector seats into the motherboard or controller header; the two female LP4 outputs accept standard 4-pin PWM fan plugs. No adapters, no pin re-mapping, no compatibility surprises — if your fans use standard 4-pin PWM, they connect directly.
• Lifetime Warranty: Passive cable construction means no capacitors, no active switching, no components subject to wear. StarTech backs the FAN4SPLIT12 with a lifetime warranty — appropriate for the product type and a meaningful differentiator over no-name splitters that offer none.
• Black Finish, Compact Form Factor: The black cable jacket blends into dark chassis interiors. At 0.4 inches tall and 0.6 inches wide, the connectors clear tight header zones that bulkier splitters can block — relevant in dense rack-mount chassis where adjacent slots are often occupied.

Integration and Compatibility

The FAN4SPLIT12 is compatible with any motherboard, NVR mainboard, or fan controller that exposes a standard 4-pin PWM (LP4) fan header — which covers the overwhelming majority of commercial and enterprise hardware produced in the last decade. Both output fans share the single header's power rail and PWM signal. One important planning note: confirm that your source header's current rating covers the combined draw of both fans. Most motherboard headers are rated for 1A (approximately 12W at 12V); a pair of moderate-duty chassis fans typically draws 0.2–0.4A each, which stays within spec, but high-performance fans or blowers with higher startup current can approach that ceiling. Check the fan manufacturer's rated current before doubling up on a single header.

This cable is a natural companion to network video recorders being assembled or upgraded for surveillance deployments, as well as edge servers used in access control and video analytics infrastructure. If you're sourcing fans or fan accessories alongside this cable, pair it with components from the StarTech accessories catalog for compatible power and cable management solutions. For rack-level thermal planning in larger security camera systems, also consider rack fan trays and airflow management panels.

Frequently Asked Questions

Q: Does the FAN4SPLIT12 support PWM speed control on both connected fans?

A: Yes. The FAN4SPLIT12 passes the PWM signal from the single source header to both output connectors, so both fans receive the same duty-cycle command and operate under the motherboard or controller's automatic speed regulation — not at a fixed voltage.

Q: What is the warranty on the FAN4SPLIT12?

A: StarTech covers the FAN4SPLIT12 with a lifetime warranty. As a passive cable with no active components, this is the expected coverage tier for the product type.

Q: Can I connect two high-performance fans using this splitter?

A: Possibly, but check your header's current rating first. Most 4-pin motherboard fan headers are rated around 1A at 12V. If your two fans together draw less than that at peak, you're within spec. Higher-draw fans — particularly blowers or larger 140mm fans — may exceed the header's current limit when both run simultaneously.

Q: What connector type does the FAN4SPLIT12 use?

A: The FAN4SPLIT12 uses LP4 4-pin PWM connectors — one male input (to the header) and two female outputs (to the fans). This is the standard 4-pin PWM format used on virtually all modern motherboard fan headers and chassis fans.

Q: How long is the cable?

A: The cable measures 12 inches (approximately 30 cm) in total length, suitable for routing between a header and fans positioned across a standard mid-tower or 2U/4U rack chassis.

Q: Is the FAN4SPLIT12 compatible with 3-pin fans?

A: Physically, a 4-pin PWM connector can accept a 3-pin fan plug (the 3-pin fan simply leaves the PWM control pin disconnected). However, a 3-pin fan cannot respond to PWM signals and will run at full voltage when connected this way. If you're mixing fan types, plan accordingly.

James Everett

The FAN4SPLIT12 is one of those components that earns its place in a deployment kit by solving a specific, recurring problem quietly — you have one fan header available and two fans to run. The 26 AWG wire gauge and LP4 PWM passthrough mean neither fan loses speed regulation, which matters when you're relying on motherboard-controlled thermal curves to keep a surveillance NVR or edge analytics node within its operating envelope over a multi-year continuous-run deployment.

Technical Highlights:

• 12-Inch Cable Length: Long enough to cross a standard 2U rack chassis interior without forcing fans into non-ideal positions, short enough that excess slack doesn't choke airflow channels — a measured choice for the target hardware format.
• 26 AWG Wire Gauge: Matched to the current requirements of standard PWM chassis fans; avoids the resistive voltage drop that thinner gauges can introduce, which would skew fan speed readings and potentially confuse thermal management firmware.
• Lifetime Manufacturer Warranty: Passive copper construction with no active components means this cable should outlast the chassis it's installed in — the lifetime warranty reflects that reality and removes it from the maintenance planning list entirely.

Deployment Considerations:

• Verify your source fan header's current rating before connecting two fans — most motherboard headers cap at 1A (12W at 12V), and two fans with higher startup draw can trip overcurrent protection or cause unpredictable speed behavior.
• Both fans receive identical PWM duty-cycle signals; you cannot independently control the speed of each fan through this splitter alone. If independent speed control per fan is required, a dedicated fan controller with multiple independently addressable channels is the correct solution instead.

The FAN4SPLIT12 is the right fit for NVR builds, edge server chassis, and access control head-end enclosures where a single spare fan header needs to drive two case fans — particularly in 2U rack-mount deployments where adding a fan controller card is not practical and thermal management still needs to remain automatic.