vault backup: 2025-12-03 17:11:42

nfpa-70_450_transformers.md

@@ -51,7 +51,7 @@ This article also covers the installation of transformers in hazardous (classifi
 
 The definitions in this section shall apply only within this article.
 
-Transformer.
+#### Transformer.
 
 An individual transformer, single or polyphase, identified by a single nameplate, unless otherwise indicated in this article.
 
@@ -76,7 +76,7 @@ Overcurrent protection shall be provided in accordance with Table 450.3(B).
 > [!important] Exception:
 > Where the transformer is installed as a motor control circuit transformer in accordance with 430.72(C)(1) through (C)(5).
 
-Table 450.3(A) Maximum Rating or Setting of Overcurrent Protection for Transformers Over 1000 Volts
+##### Table 450.3(A) Maximum Rating or Setting of Overcurrent Protection for Transformers Over 1000 Volts
 (as a Percentage of Transformer-Rated Current)
 
 %% TODO %%
@@ -94,7 +94,7 @@ Notes:
 
 4. A transformer equipped with a coordinated thermal overload protection by the manufacturer shall be permitted to have separate secondary protection omitted.
 
-Table 450.3(B) Maximum Rating or Setting of Overcurrent Protection for Transformers 1000 Volts and Less (as a Percentage of Transformer-Rated Current)
+##### Table 450.3(B) Maximum Rating or Setting of Overcurrent Protection for Transformers 1000 Volts and Less (as a Percentage of Transformer-Rated Current)
 
 %% TODO %%
 
@@ -341,16 +341,16 @@ Transformers, other than Class 2 or Class 3 transformers, shall have a disconnec
 
 ### 450.21 Dry-Type Transformers Installed Indoors.
 
-#### 450.21(A) Not Over 1121⁄ 2 kVA.
+#### 450.21(A) Not Over 112 1⁄2 kVA.
 
 Dry-type transformers installed indoors and rated 1121⁄ 2 kVA or less shall have a separation of at least 300 mm (12 in.) from combustible material unless separated from the combustible material by a fire-resistant, heat-insulated barrier.
 
 > [!important] Exception:
 > This rule shall not apply to transformers rated for 1000 volts, nominal, or less that are completely enclosed, except for ventilating openings.
 
-#### 450.21(B) Over 1121⁄ 2 kVA.
+#### 450.21(B) Over 112 1⁄2 kVA.
 
-Individual dry-type transformers of more than 1121⁄ 2 kVA rating shall be installed in a transformer room of fire-resistant construction having a minimum fire rating of 1 hour.
+Individual dry-type transformers of more than 112 1⁄2 kVA rating shall be installed in a transformer room of fire-resistant construction having a minimum fire rating of 1 hour.
 
 > [!important] Exception No. 1:
 > Transformers with Class 155 or higher insulation systems and separated from combustible material by a fire-resistant, heat-insulating barrier or by not less than 1.83 m (6 ft) horizontally and 3.7 m (12 ft) vertically.
@@ -369,7 +369,7 @@ Dry-type transformers rated over 35,000 volts shall be installed in a vault comp
 
 Dry-type transformers installed outdoors shall have a weatherproof enclosure.
 
-Transformers exceeding 1121⁄ 2 kVA shall not be located within 300 mm (12 in.) of combustible materials of buildings unless the transformer has Class 155 insulation systems or higher and is completely enclosed except for ventilating openings.
+Transformers exceeding 112 1⁄2 kVA shall not be located within 300 mm (12 in.) of combustible materials of buildings unless the transformer has Class 155 insulation systems or higher and is completely enclosed except for ventilating openings.
 
 ### 450.23 Less-Flammable Liquid-Insulated Transformers.
 
@@ -451,7 +451,7 @@ Oil-insulated transformers installed indoors shall be installed in a vault const
 
 * (2) Safe egress is provided for personnel.
 
-* (3) A minimum 6-mm (1⁄ 4-in.) steel barrier is provided for personnel protection.
+* (3) A minimum 6-mm (1⁄4-in.) steel barrier is provided for personnel protection.
 
 ### 450.27 Oil-Insulated Transformers Installed Outdoors.