---
id:
aliases:
  - nec-450
tags:
  - authorship/other
  - destiny/uncertain
  - status/incomplete
  - topic/construction/electrical
  - type/media
title: "Article 450: Transformers and Transformer Vaults (Including Secondary Ties)"
---
# Article 450: Transformers and Transformer Vaults (Including Secondary Ties)

## Part I. General Provisions

### 450.1 Scope.

This article covers the installation of all transformers.

Exception No. 1:
Current transformers.

Exception No. 2:
Dry-type transformers
that constitute a component part of other apparatus
and comply with the requirements for such apparatus.

Exception No. 3:
Transformers that are an integral part
of an X-ray, high-frequency, or electrostatic-coating apparatus.

Exception No. 4:
Transformers used with Class 2 and Class 3 circuits
that comply with Article 725.

Exception No. 5:
Transformers for sign and outline lighting
that comply with Article 600.

Exception No. 6:
Transformers for electric-discharge lighting
that comply with Article 410.

Exception No. 7:
Transformers used for power-limited fire alarm circuits
that comply with Part III of Article 760.

Exception No. 8:
Transformers used for research, development, or testing,
where effective arrangements are provided
to safeguard persons from contacting energized parts.

This article covers the installation of transformers
dedicated to supplying power to a fire pump installation
as modified by Article 695.

This article also covers the installation of transformers
in hazardous (classified) locations
as modified by Articles 501 through 504.

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