BC30J-M/E4X REX 300KVA 600-120/208V 3PH ISO TRANSFORMER

For a 300 KVA, 3-phase, 600V primary transformer, the full-load primary current is approximately 289A (300,000 ÷ (√3 × 600)). Per the Canadian Electrical Code, primary overcurrent protection is typically set at 125% of full-load current for transformer protection, which would point to a 350A or 400A breaker depending on your specific installation and CEC Rule 26-256 requirements. We recommend consulting your electrical engineer or AHJ to confirm the exact sizing for your application.

The BC30J-M/E4X is an ISO (isolation) transformer designed primarily for indoor commercial and industrial use. For outdoor installations in Canadian conditions, you would typically require an enclosure with an appropriate NEMA/IP rating for weather protection. Contact our team with your installation environment details and we can advise on suitability or recommend appropriate enclosure options.

Rex transformers, including the BC30J-M/E4X series, can be difficult to source as some models have been phased out of regular production. Northern Breaker Group specializes in hard-to-find and obsolete electrical equipment — we maintain stock of legacy units and can source compatible 300 KVA 600-120/208V 3-phase ISO transformer alternatives from other reputable manufacturers. Reach out to our Calgary, Edmonton, or Vancouver counters for current availability and lead times.