This article covers バッファロー 3ピン⇒2ピン変換アダプター ブラック BSTAPA01BK (× 2).

Overview

The Buffalo BSTAPA01BK is a simple but essential power conversion adapter that lets you connect devices with a 3-pin (grounded) plug into standard 2-pin outlets commonly found in Japanese homes. Sold as a 2-pack, it's perfect for grounding large appliances like refrigerators, washing machines, and microwaves in older or rental properties where only two-pin sockets are available. The built-in earth wire (approx. 12 cm) allows you to maintain a ground connection for safety.
Measuring just 30×30×45 mm and weighing 25 grams, the adapter is compact enough not to block adjacent outlets. Its plain black finish blends into any room. The earth wire terminates in a Y-type crimp terminal that can be screwed onto a nearby ground point (e.g., metal plumbing or a dedicated ground terminal).

Connectivity & Compatibility

This adapter converts a standard Japanese 3-pin plug (earthing type) to a 2-pin receptacle. The male side accepts a 3-pin plug (with earth pin), while the female side is a 2-pin socket plus an independent earth wire. It's compatible with any 100V household appliance that uses a 3-pin plug and requires grounding, including air conditioners, refrigerators, washing machines, microwave ovens, and computers with three-prong cords.
The earth wire is only 12 cm long, so the ground connection must be extremely close to the outlet. Common ground points include exposed metal pipes, the screw on a grounded outlet faceplate, or a dedicated grounding terminal. The adapter itself carries no active electronics; it's just a passive converter. Rated current is not explicitly stated but should handle up to 15A for typical Japanese household circuits.

Product Info

Buffalo is a well-known Japanese manufacturer of PC peripherals and accessories, but they also produce practical household items like this power adapter. The BSTAPA01BK (2-pack) launched around mid-2024 and is widely available through online retailers and electronics retailers at about ¥1,100. No extended warranty is offered given its simple construction, but Buffalo's standard 1-year limited warranty applies. No manual is included—installation is straightforward.
Market positioning is entry-level: it's an affordable, no-frills solution for a common compatibility problem. No premium materials, just reliable functionality.

Best Use Cases

  • Renters with 2-pin outlets only: Many Japanese rental apartments lack 3-pin receptacles. This adapter allows you to ground your refrigerator, washing machine, or microwave properly. Ensure you have a nearby ground point within 12 cm.
  • Homeowners in older houses: If your home was built before 3-pin outlets became standard, this adapter lets you safely use modern appliances without rewiring. Always connect the earth wire to minimize shock risk.
  • Temporary or DIY setups: For repair work, event equipment, or moving into new spaces, having a couple of these adapters on hand is handy. They also work as a cheap way to extend a ground connection if you attach an additional longer earth wire.
    Not suited for users who cannot reach a ground point within 12 cm, or for high-power appliances exceeding 15A. If you don't care about grounding at all, any 3-to-2 adapter will work, but safety is compromised.