15 Minute Tech Talk - Selective Coordination Tables
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- Опубликовано: 7 фев 2025
- Some fundamentals that you need to know to save you money and time when it comes to selective coordination.
This session will review resources and some tricks of the trade that can make the power systems engineer's life so much easier.
Join in on this discussion.
Here are some resources for your selective coordination library:
www.eaton.com/...
Selective Coordination Circuit Breaker Applications:
www.eaton.com/...
Selective Coordination Fuse Applications:
www.eaton.com/...
Glad someone else other than me is introducing these charts to engineers. That said, the first part of the lecture implies that you cannot use TCC plots to determine misscoordination down in the .01 sec range other than charts. As plotted the 20A and 150A breakers were coordinated for the situation shown. That is because the plot truncated the right most portion of the 20A breaker at a "desired level" for analysis. If you truncated the 20A curve at 1500A or 3000A you would have seen the same result as the charts show. I have been covering this in my courses since 2006 at which time G.E. engineers attending the course decided to start making up the coordination charts that thankfully most of the other manufacturers now provide. The biggest problem I see is that engineers really don't understand the equipment and what the plotted curves are telling them. Later a TCC with a current limiting fuse is plotted downstream of a breaker. That coordination will work but that is another place where TCC plots can fool you. Just because there is what I call "white space" between the CL fuse and the breaker does not guarantee coordination between them. That is where again mfr. charts with fuses and breakers can guarantee coordination. The details of all of this can be found in a course at : www.quadrelec.com. Thanks Tom for presenting these charts to the engineers as there are too many studies that do not come to the correct conclusion and therefore are worthless.
Awesome explanation. I do QC for a large electrical contractor in the DC area at different data centers were building and this really helped me start to understand what’s involved in the coordination of all the ocpd’s. You mentioned that coordination is a code requirement but also said that some customers don’t care about upstream devices opening from a downstream fault. Are there situations where coordination is not an NEC requirement?
Great content. At the same time you are not only teaching useful items but also giving real product support
I appreciate that!
Just joined 👍🏾
Quite useful
Selective coordination with tested pairs in fuse applications: one issue with this is that many disconnects accept different fuse manufacturers. There's no requirement in the NEC to put a label on a disconnect using this method, to inform a future service person to replace only with a certain manufacturer's fuse.