4000 amp Bolt-Loc switches

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Davebones

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We have 4000 amp , 1600 amp , and 1200 amp Sq D bolt-loc switches on one of our main switchgear sections in the plant . After a engineering study for Arc Flash update it was recommended these switches be replaced with breakers . We try to have these switches PM every three years and they are in a clean environment . The switches have been installed for about 40 yrs . This a aerospace manufacturing plant so any length of time down could be costly if we had a issue with one . Just wondered do you guys see a lot of these still in service and your take on replacing them ?
 
Part of the arc flash energy problem with using fuses is relatively long clearing times when the available arcing fault current is below the current limiting point of the fuses. In these cases, breakers with adjustable instantaneous trip points might be able to clear the arc faster. When I taught classes, I used an example of a 1600A device feeding an MCC with 150ft of parallel conductors, the fuses were more than 40cal/cm^2 while the breaker was less than 8.

If lowering incident energy is your concern, maybe you could add a 'maintenance' switch and relay, as is now required in the NEC, rather than complete replacement.
 
Davebones said:
Our main concern is support and parts for these bolt-loc switches due to the age .
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That should be a concern for any product, including breakers.

What is the expected service life, from the manufacturer? Are there non-manufacturer repair parts are available ? How many of these items are available in the used/refurbished market?

There have been times, I recommended replacing non-maintained switches.
 
Everything -- Everything -- has a Service Life. And yeah, as part of Arc Flash and even mission critical power -- to run on Ancient and Antique Equipment is not such a good plan.

Generally the only time(s) I still encounter stuff like this (some earlier this year) is for an Arc-Flash Study . . . that turns into a Service Equipment Replacement. But as you noted for an aerospace environment, the challenge is the down-time (but if you wait long enough, it will schedule itself ;) ) Guess we know what you will be doing during the 2 week Christmas - New Year break.

Your next concern will probably be lead time on the New Equipment. The best lead times we are getting is 6 months or more -- and that is the fastest from custom builders. Eaton, SqD, Siemens -- were all talking 9 months to a year last time I checked.
 
i am currently quoting replacement of 3 3000A bolt-loc switches for a client as they have had several scares and it is nearly impossible to locate any replacement parts. if something were to fail, there is no possible way of getting the issue resolved and the plant back up and running in an acceptable timeframe.
 
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