Equipment damage for wrong sizing
Equipment damage for wrong sizing
(OP)
Hello everybody,
I was wondering if some of you may have some information about statistical indexes of:
a) Equipment damage because of being wrong sized, related to circuit breakers, transformers, surge arresters, and so on.
b) As well as some indexes of spurious operations of relays because of wrong settings?
Does anybody have some information related to theses items?
If affirmative,I would thank you to share it.
Best Regards
I was wondering if some of you may have some information about statistical indexes of:
a) Equipment damage because of being wrong sized, related to circuit breakers, transformers, surge arresters, and so on.
b) As well as some indexes of spurious operations of relays because of wrong settings?
Does anybody have some information related to theses items?
If affirmative,I would thank you to share it.
Best Regards






RE: Equipment damage for wrong sizing
Alan
"The engineer's first problem in any design situation is to discover what the problem really is." Unk.
RE: Equipment damage for wrong sizing
I thank your reply, however, what I am looking for is some updated and real data, based on experiences.
We have some "engineers" that according to their experience it is not needed to size equipment above calculated shortcircuit levels because, a possibility of a fault damaging the switchgears or circuit breakers is very low.
Because of that, I would like to get some feedback coming from experiences of real engineers about some events that may have damaged some equipments.
I hope somebody may provide some data
RE: Equipment damage for wrong sizing
Alan
RE: Equipment damage for wrong sizing
RE: Equipment damage for wrong sizing
There are so many more issues here than just equipment. If you undersize equipment and someone dies than you are really going to be up shit creek.
RE: Equipment damage for wrong sizing
Regardless of what the index would say, what is important is that you do not become one of those statistics!
Rafiq Bulsara
http://www.srengineersct.com
RE: Equipment damage for wrong sizing
Glad to hear that we can throw away the standards and no longer need to test and rate equipment since none of it matters anyway.
Should make switchgear cheaper and save a lot of money!
Alan
RE: Equipment damage for wrong sizing
If you are in the U.S., the failures you will need to be counting will most likely be reported recorded by OSHA if anyone is injured. Other than that, those statistics are going to be a carefully guarded by manufacturers who track them.
I agree with the other replies. Underrating for fault current is never acceptable.
Alan
"The engineer's first problem in any design situation is to discover what the problem really is." Unk.
RE: Equipment damage for wrong sizing
1. Possibility of interchanging CB with different ratings during maintenance.
2. We also take into consideration where the Swgr are to be installed, for the likelihood of incidents like lightning (outdoor swtgr)
RE: Equipment damage for wrong sizing
I thank your comments!
Precisely, what I would like to know is, if you have had some experiences in which because of underrated equipment or incorrect settings some problems have happened and how often.
In Mexico, there is a code like NEC (in fact is a traslation of it) however, some large equipment manufacturers always tend to underrate equipment and it is very difficult to convince them that economical decisions must be based on technical reassons.
In some cases, short-circuit calculation done by the same manufacturer says "minimum value is x" but when you see the equipment name plate shows a value lower than "x".
Of course, there are discussions and so on but, it is very difficult to convince them despite having enough technical data and arguments, simply project managers do not understand technical reassons, only economical ones.
Final clarification: What I am talking about are some specific cases, I mean, it is not the rule to do wrong things in most of the projects, ok?
Best Regards