We take cryptocurrency — so the coins you hold can buy real hardware.Pay in crypto, spend it on real hardware. Free insured shipping worldwide over $399. Plain, unbranded boxes, sent from Germany.Free insured shipping over $399. Your rate is locked for 30 minutes once checkout opens.Rate locked 30 minutes. Every item sealed, serial-checked and covered by a 24-month warranty.Sealed, 24-month warranty.

Saved items Sign in
Small black rectangular USB isolator with two ports

Black Box Corporation

Black Box Corporation SP387A 1 Port USB to USB Isolator (4Kv) wired accessory

SKU CH-97FM-VB884 MPN SP387A

Provides 4 kV isolation for a single USB connection to protect equipment from ground loops and voltage spikes

  • Provides 4 kV galvanic isolation for USB devices
  • Single port design isolates one USB connection
  • Protects sensitive equipment from ground loops
  • Prevents voltage spikes from damaging connected hardware
  • Maintains data integrity across isolated USB link

Isolator for USB Protection

The Black Box SP387A provides a single-port USB to USB isolation barrier rated at 4Kv. It sits between a host computer and a peripheral to break ground loops and block transient voltages. This wired accessory suits industrial, medical or laboratory environments where electrical noise or fault currents threaten sensitive equipment or data integrity.

Compact Inline Form Factor

The unit installs inline without requiring external power or driver installation on supported operating systems. Its plug-and-play design preserves standard USB signalling while the isolation circuitry handles the electrical separation. The rugged housing withstands repeated connection cycles in demanding day-to-day use.

4Kv Isolation Rating Decides Fit

The 4Kv withstand voltage is the critical specification that determines whether this isolator meets a given safety or noise-rejection requirement. Buyers needing lower isolation levels or multiple simultaneous ports should verify those needs against this single-port rating before purchase.

How it compares

Measured against everything we stock in Network Cabling Accessories, at today’s prices. Recalculated every night.

Price $144.99
Pricier than about 88% of the 800 comparable items (median $18.99).

New to this? Which coin should you pay with — what to check, what it costs to pay, and what is never asked for.

Specifications

Size & build
Shipping weight0.45 kg
Package size203 × 188 × 89 mm

Questions about this item

Does the 4 kV isolation on this SP387A isolator limit the USB data rate to USB 1.1 speeds?

The 4 kV galvanic isolation protects connected equipment from ground loops and voltage spikes while allowing the USB port to operate at its native signalling rate.

What physical space and port orientation does the single-port SP387A require for mounting?

The compact inline housing plugs directly into a standard USB Type-A socket and adds only a short dongle length, so it fits alongside adjacent ports without blocking them.

Is any driver installation or configuration step required before the SP387A begins isolating the USB connection?

The isolator is fully hardware-based and driverless; simply insert it between the host and the peripheral and the 4 kV isolation is active immediately.

More in Network Cabling Accessories

Similar items