Emergency System Generator Sizing and Load Testing

First, calculate the total emergency load: life safety 50 kVA + critical 80 kVA + equipment 100 kVA = 230 kVA. The generator is rated 200 kW at 0.8 PF, which is 250 kVA. So the generator can supply 250 kVA continuously, which is greater than 230 kVA. However, NEC 517.30 requires the essential electrical system to be divided into branches, and the generator must be sized to supply the load. But we must consider demand factors? For hospital emergency systems, the load is typically taken at 100% for life safety and critical, but equipment branch may have demand factors? Actually, NEC 517.30(C) requires the generator to be sized to supply the load, but there are requirements for the generator to be able to supply the load within its rating. The 200 kW generator at 0.8 PF gives 250 kVA, which is greater than 230 kVA, so it appears adequate. However, we must also consider the UPS: the UPS is 100 kVA, but it may be on the equipment branch or critical branch? The problem does not specify. If the UPS is part of the critical branch, then the 80 kVA critical branch might include the UPS? But the UPS is 100 kVA, which is larger than the critical branch. So likely the UPS is on the equipment branch or separate. We need to clarify. Actually, the problem states the connected emergency loads are life safety 50, critical 80, equipment 100. The UPS is additional? It says the hospital also has a 100 kVA UPS. That might be part of the critical branch? But the critical branch is only 80 kVA, so the UPS cannot be on it. So the UPS is likely on the equipment branch or is a separate load. But the generator must supply the UPS if it is part of the emergency system. So total load might be 230 + 100 = 330 kVA, which exceeds the generator's 250 kVA. So the generator is undersized. However, the problem might expect us to consider that the UPS is not a generator load because it has its own batteries? But the UPS needs to be recharged, so it is a load. So I think the generator is undersized if the UPS is on the emergency system. But the problem does not specify the UPS is on the emergency system. So we should state assumptions. The model answer should analyze both scenarios. Also, NEC 700.5 requires the generator to have enough capacity to supply the load. So if total load is 230 kVA, generator 250 kVA is adequate. But we must also consider the 2-hour rating at 250 kW? That is 312.5 kVA, but that is for limited time. The continuous rating is 250 kVA. So for continuous load, 230 kVA is fine. But we must also consider starting loads, especially motor loads. The problem does not give motor details. So a conservative answer: the generator is adequately sized for the 230 kVA load, but if the UPS is included, it is not. So recommend verifying the UPS connection.

NEC 700.4 requires the generator to be tested and maintained per NFPA 110. NFPA 110 requires monthly testing of the generator under load for at least 30 minutes. The problem states the generator is tested monthly for 30 minutes under load, which meets the requirement. However, NFPA 110 also requires an annual load test at 100% of the nameplate rating for 2 hours. The generator has a 2-hour rating at 250 kW, so it can be tested at that load. But the monthly test is typically at 30% load or more. So the current testing is compliant for monthly, but annual testing must be performed. Also, the generator must be exercised at least once a month. So the answer: monthly 30-minute test is compliant, but annual load test at 100% for 2 hours is also required. Additionally, the generator must be tested with the emergency system loads connected. So recommend adding the annual test.