What is the minimum working space depth required in front of an electrical panel rated 200 A, 120/240 V, located in a dry room, opposite a concrete block wall?

Question: What is the minimum working space depth required in front of an electrical panel rated 200 A, 120/240 V, located in a dry room, opposite a concrete block wall?

Answer options:

• 600 mm (2 ft)
• 750 mm (2.5 ft) ✅ 900 mm (3 ft)
• 1 m (3.3 ft)

Correct answer: 900 mm (3 ft)

Explanation: According to CEC Rule 2-308(1) Table 6, for equipment operating at 151-600 V to ground (Condition 1, 0-150V to ground and Condition 2, 151-600V to ground) and where exposed live parts are on one side and a grounded surface on the other (Condition 2), the minimum depth of working space is 900 mm (3 ft). A 240 Vac panel with 120 V to ground falls into Condition 2. For 0-150V to ground, Condition 1 is 750 mm. A 200A panel is typically a significant service. The correct condition for 120/240V, 200A would be condition 2 of Table 6 since a grounded concrete block wall represents a grounded surface opposite a panel, and 240V nominal voltage. Therefore, 900 mm (3 ft) is the minimum depth.