MidNite Solar MNSPD-300-DC Surge Protection Device – 300VDC, Type 1 SPD

The MidNite Solar MNSPD-300-DC is a Type 1 surge protection device designed to shield both AC and DC systems from transient events. Built to UL1449 rev3 standards, it protects service panels, load centers, and directly connected electronics, making it a versatile choice for traditional grid setups and off‑grid configurations alike.

What it protects

• Service panels and load centers in mixed AC/DC environments
• Classic and other charge controllers used in solar systems
• Off‑grid PV combiners and related DC circuits up to 300 V
• 120/240 VAC circuits where SPD protection is required

Key benefits and specifications

• Environmental Rating: Type 4X (Outdoor) for durable, weather‑resistant protection
• Warranty: 5 years for long‑term confidence
• Made in the USA, with a compact footprint that fits in tight spaces
• Dimensions: 4.4" L x 3.8" W x 3.5" D; Weight: 1 lb

The DC variant can protect all DC circuits up to 300 volts and also accommodates typical 120/240 VAC circuits. The core protection remains consistent across AC and DC configurations; what changes is how the indicator lights are powered. This means you can deploy the device in a wide range of solar or grid installations without compromising safety or performance.

How it works in real life

Think of the MNSPD‑300‑DC as a barrier that helps smooth out electrical spikes before they reach sensitive components. In outdoor installations, a rugged enclosure keeps moisture and dust at bay, while the compact form fits neatly alongside inverters, charge controllers, or inside a service enclosure. When used in mixed systems, you’ll notice that the LEDs adapt to the supply type, providing clear status feedback appropriate to the setup, while the protection electronics stay the same.

Ideal use cases

• Protecting solar charge controllers and DC paths in off‑grid systems
• Adding safeguarding for AC load centers and distribution panels in hybrid setups
• Shielding 120/240 VAC circuits in residential or small commercial solar projects
• Outdoor deployments on rooftops or external walls where weather exposure is a concern

In practice, this device offers a practical layer of protection that can help reduce arcing and transient damage to connected equipment. While it does not guarantee results, it provides an additional margin of protection that aligns with common off‑grid and grid‑tie installation needs.