FEC2 wrote:
Zog, thanks for the tip. CBS has designed such a remote switch to work on a pringle but has not manufactured any yet. It is cheaper than going to say a static trip breaker but costlier than fabricating your own extender bar when all you need is 6-12 inches to get below 40 cal/cm2. In a case like I described earlier, the cbs switch makes a lot of sense (many swithces on site, high energy...)
Just adding an extension to get it below 40cal is not my idea of mitigation, the worker is still suited up a 40 cal suit and in the flash protection boundary. Better to do it right and be outside the FPB. The arc safe people can have something like this developed and produced in a few weeks.
FEC2 wrote:
We run into a lot of situations where a customer has something like a 2500 kVA transformer feeding a set of 3000A Class L fuses at 480V for their main gear. Often the available fault current and the fuse melt curve align so that even the sub-fuse or breakers are above 40 cal. What are people hearing out there from equipment manufacturers for more cost effective retrofits (i.e. arc flash relays, new fuse technology...)?
There may be better solutions for mitigation but I don't know the details of your system, but experminting with some different fuses can make a huge difference.