How to Choose the Right Surge Protective Device

1. Understand whether you need a parallel SPD or a series SPD.

(1) Under European regulations, both parallel and series SPDs must include a working indicator light. However, U.S. regulations do not have this mandatory requirement.

(2) We recommend that customers choose parallel SPDs with an indicator light, because the light helps determine whether the SPD is still functioning. For series SPDs, an indicator light is optional due to the nature of the circuit, and omitting it can reduce cost.

(3) Functional differences between parallel and series SPDs:

a. When using a parallel SPD, if lightning damages the SPD, the luminaire still operates normally as long as the driver and LED source are intact. However, the SPD is no longer providing protection, and during the next lightning strike, both the driver and the LED source may be damaged simultaneously.
b. When using a series SPD, if lightning damages the SPD, the luminaire will stop working—but the driver and LED light source remain unharmed. Replacing the failed SPD restores normal operation.

(4) Parallel SPDs typically have 3 wires. Series SPDs may have 4, 5, or 6 wires, with 4-wire versions being the most common.

(5) As the saying goes, “There are exceptions to every rule.”

Our GSPD 4 model has 6 terminals but is still a parallel SPD. It can also be manufactured as a series SPD upon customer request.
Additionally, the GSPD 4 enclosure includes a built-in window for an indicator light. If the light is not installed, it leaves an open hole that affects appearance and makes it easier for dust to enter. Therefore, both parallel and series versions are normally made with indicator lights.
We strongly recommend using series SPDs when the SPD is installed inside the luminaire and connected directly to the LED driver.

2. Appearance: Determine whether you need a single-sided cable outlet or dual-sided cable outlet.

(1) Our GSPD 1 and GSPD 3 series use single-sided cable outlets.
(2) GSPD 4, M997, and GSPD 5 use dual-sided terminal connections.
(3) GSPD 1 can be made with electronic wires or power cables.
(4) Single-sided SPDs can be manufactured as either parallel or series types. Dual-sided SPDs can **only** be manufactured as series types.

3. Determine whether you need a 10kV SPD or a 20kV SPD.

Currently, 10kV SPDs are the most widely used model in the industry. 20kV is used for environments with high lightning activity or strict protection requirements.

4. Determine what safety certifications are required.

The major global SPD certifications include:
- U.S. standards (ETL / UL)
- European standards (TÜV / CE)
- Chinese standards (CQC)
Our company provides SPDs with all major global certifications, ensuring compliance and safety across markets.

5. Reference: Meaning of cable color codes in China, Europe, and the United States.

China:

- Live (L): Red
- Earth (E): Yellow-Green
- Neutral (N): Blue

Europe:

- Live (L): Brown
- Earth (E): Yellow-Green
- Neutral (N): Blue

United States:

- Live (L): Black
- Earth (E): Green
- Neutral (N): White