Circuit Breaker Testing

Q: During a recent survey, the inspector cited us for not exercising our circuit breakers downstream of our generator. Does the LSC require annual exercising of all circuit breakers between the generator and the connected load?

A: The LSC section 9.1.3 does require emergency power generators to comply with NFPA 110 Standard for Emergency and Standby Power Systems, 1999 edition. Section 6-4.6 of NFPA 110 requires the main and feed circuit breakers between the generator and the transfer switch terminals to be exercised annually with the generator in the off position. This appears to me that all emergency source circuit breakers are required to be exercised annually.  This would include the generator output breaker and all downstream distribution breakers, up to and including any breakers that feed the emergency feed side of the automatic transfer switch (ATS).  I believe that would exclude any loads connected to the load side of the ATS such as motors, lights, pumps, etc.  The process is a simple one because all affected breakers are normally in a de-energized state. I do not recall ever seeing a reason for this procedure published, although I’m sure there is a good reason.  In my experience though, breakers that are not exercised regularly can be extremely (if not impossible) to reset, even though the internal trip mechanism may work perfectly. This may lead an organization to not conduct this annual test, which may result in them being cited for noncompliance. Some organizations will purchase replacement circuit breakers and have them available on a shelf in case the breaker will not reset. While this is a very proactive approach to testing and a quick response to potential repairs, it can be rather costly as the large current breakers are a bit pricey. While this issue may not come up very often during a survey, it is a LSC requirement and the surveyor has the obligation to cite the issue if he or she sees it as being noncompliant.

Combined load tests on generators

Q: The AHJs who inspect my hospital require that I conduct a three-year, four-hour load test, which we do simultaneously with our annual load bank test. One AHJ says this is acceptable while another AHJ doesn’t like it and says the annual load test is required to be conducted at varying loads of 25%, 50%, and 75%, and the three-year test is required to be conducted at 30% load. Which one is correct, and where do I find the standards for this testing requirement?

A: Both The Joint Commission and CMS require the three-year, four-hour generator load test, which was introduced in the 2005 edition of NFPA 110, Emergency and Standby Power Systems. This test was further explained in the following 2010 edition of the same NFPA 110 standard. Section 8.4.9 of NFPA 110 requires the three-year test to be conducted at 30% of the nameplate rating of the generator for four continuous hours. The annual load test is only required when the monthly load tests cannot meet the 30% nameplate rating capacity. The annual load test is required to operate the generator at 25% capacity for 30 minutes, 50% capacity for 30 minutes and 75% capacity for 60 minutes for 2 continuous hours. If you combined these two load tests, then the one AHJ is correct; 25% capacity is not equal to 30% capacity for the first 30 minutes of the load test, and that AHJ would be correct for refusing to accept this combined test as evidence of meeting the three-year, four-hour load test. An easy solution to this would be to operate the first 30 minutes of the combined test at 30% capacity, as the load values given are minimum values and may be exceeded.

Emergency Generator Batteries

Q: Are we required to replace the batteries that start our emergency generators every two years? Our generator service contractor told us that the code requires us to replace the batteries that often.

A: I’m not sure what code your service contractor is referring to, but I’m not aware of this requirement. Section 19.5.1 of the LSC requires compliance of section 9.1 for all utilities. Section 9.1.3 requires emergency generators to comply with NFPA 110 (1999 edition) Standard for Emergency and Standby Power Systems. Section 6-3.6 of NFPA 110 requires the batteries to be maintained according to the manufacturer’s specifications and inspected at intervals of not more than 7 days. The annex section states that the specific gravity should be checked and recorded. I suggest that you contact your local and state authorities to see if they have any other requirements.

Generator 3-Year Load Test

Q:  We are completing a project that includes a new generator for our hospital. The installing contractor will conduct a 2-hour load test as part of his commissioning. My question is, are we required to conduct the 3-year 4-hour load test right away, or should we wait 3 years after we begin using the generator?

A:  You need to conduct this 4-hour test right away. The Joint Commission standards references NFPA 110 Standard for Emergency and Standby Power Systems (2005 edition) and section 8.4.9 requires a 4-hour load test once every three years. If you wait until the third year to do this test, and you have a survey prior to completing this test, you may be cited by the accreditor for non-compliance with their standards. It is the intent of this test to provide a reasonable assurance that the generator is capable of running and delivering power during an emergency. It has been documented that some generators failed to continue to operate after only a couple of hours during an emergency due to overheating.