Medium voltage switchgear Webcast: Your questions answered
Jeff Jordan, offer manager for metal-enclosed products, Schneider Electric, answered additional questions on how to increase reliability and decrease cost from the Oct. 6 webcast on medium-voltage switchgear.
Question: Any thoughts on the need for proper PPE for employee safety?
Answer: Schneider Electric recommends consulting the NFPA 70E standard for the selection of personal protective equipment (PPE) based on the particular Incident Energy calculation of any given installation. Each installation is different.
Q: Are the CPT’s and PT’s are fused separately?
A: Yes, the HVL/cb fixed breaker includes traditional voltage transformers. By the code, these must have fuses. Our design accommodates up to 5 fuses. That’s enough for 3 individual phases of a Wye PT configuration and 2 more for the control power transformer (CPT).
Q: Are arc flash lowering components available?
A: Yes, there are several methods to detect and mitigate an arc flash. All Square D by Schneider Electric medium voltage breakers interrupt in 3-cycles, which is within 50 ms (as compared to 100 ms for comparable switchgear). Since incident energy is a function of the duration (time) of the arc, faster breakers significantly lower the risk. Additionally, arc flash relays and arc resistant enclosures are offered in both fixed or withdrawable switchgear.
Q: For 10-year PM’s, is Schneider saying that breakers will not need to be exercised for 10 years?
A: The maintenance interval is 10 years for our new generation of fixed breaker switchgear. This is the amount of time between scheduled outages for inspection of the components inside the switchgear. In addition, Schneider Electric recommends exercising the breaker, by opening and closing it, at least one time each year. This activity, which does not require access to the inside of the switchgear, will help ensure that it is ready to trip on demand in the event that it is called upon to do so.