---
title: "What Is Type 1 SPD? Electrical Glossary | Daniel Electric"
description: "A Type 1 SPD installs before or at the main breaker panel, where it can stop outside surges from lightning or utility switching."
url: https://danielelectric.multisites.ai/glossary/type-1-spd
publisher: Daniel Electric
phone: +1-817-481-8606
quote: https://danielelectric.multisites.ai/contact
---

Safety devices

# Type 1 SPD

A Type 1 SPD installs before or at the main breaker panel, where it can stop outside surges from lightning or utility switching.

Leviton says Type 1 devices install before or at the main breaker panel and protect against external surges, such as lightning or utility capacitor bank switching. It adds that Type 1 devices can be used in Type 2 applications. A summary of NEC Article 230.67 says dwelling services need a Type 1 or Type 2 device.

Because a Type 1 unit connects ahead of the [main breaker](https://danielelectric.multisites.ai/glossary/main-breaker), the wires at that point stay energized. That makes it work for a licensed electrician. Compare a [Type 2 SPD](https://danielelectric.multisites.ai/glossary/type-2-spd). See [whole-house surge protector installation](https://danielelectric.multisites.ai/whole-house-surge-protector).

[Daniel Electric can helpWhole-house surge protector installation](https://danielelectric.multisites.ai/whole-house-surge-protector)

## Related terms

-   [Type 2 SPD](https://danielelectric.multisites.ai/glossary/type-2-spd)
-   [Surge protective device](https://danielelectric.multisites.ai/glossary/surge-protective-device)
-   [Whole-house surge protector](https://danielelectric.multisites.ai/glossary/whole-house-surge-protector)
-   [Main breaker](https://danielelectric.multisites.ai/glossary/main-breaker)

## Sources

1.  [Leviton: Surge Protective Devices (SPDs) brochure](https://leviton.com/content/dam/leviton/commercial-industrial/product_documents/brochure/Surge%20Brochure%20Condensed%20Q-1186H%20(1)%20(2).pdf)
2.  [Leviton: NEC Code Requirements For Surge](https://leviton.com/products/commercial/surge-protection/nec-code-requirements-for-surge)

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## Need an electrician in Southlake?

Call and tell us what is going on. A photo of the panel label or the problem helps us come prepared. Quotes on new installations are free.

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