Conditions2 | Minimum Clear Distance3 | Minimum Clear Distance3 | |||
0 - 150 volts to ground | 151 - 600 volts to ground | ||||
A1 | 3 ft. | 3 ft. | |||
B | 3 ft.1 | 3 1/2 ft. | |||
C | 3 ft. | 4 ft. |
1. | Minimum clear distances may be 0.7 m (2.5 ft) for installations built before April 16, 1981. |
2. | Conditions A, B, and C are as follows: |
A = Exposed live parts on one side and no live or grounded parts on the other side of the working space, or exposed live parts on both sides effectively guarded by suitable wood or other insulating material. Insulated wire or insulated bus bars operating at not over 300 volts aren't considered live parts. | |
B = Exposed live parts on one side and grounded parts on the other side. | |
C = Exposed live parts on both sides of the workspace (not guarded as provided in condition A with the operator between the panels). | |
3. | Working space is not required in back of assemblies such as dead-front switchboards or motor control centers where there are no renewable or adjustable parts (such as fuses or switches) on the back and where all connections are accessible from locations other than the back. Where rear access is required to work on deenergized parts on the back of enclosed equipment, a minimum working space of 30 in. horizontally must be provided. |