What Does the Rupturing Capacity Means for Copper Busbars

Are ou possibly referring to the breaking capacity of the feeder-side protection device?

A such copper busbars are not switching devices but maybe you mean something else.

It's the amperage that makes the busbar go:boom

Interview questions answered here:

define breaking capacity of busbar & how it is calculated?

Sorry for not being a native English speaker but I always thought that busbars as such don't have any breaking capacity.

There are short circuit withstanding specifications which are used to dimension the protection devices to guarantee that the short-circuit rating of the busbar system (indeed including also other components of course) cannot be exceeded in the worst case (maximum prospective short circuit current).

I don't remember the details of the abreviations and exact terms and definitions by heart.

Sorry, I was being naughty.

Electricity is not my first language.

But, the breaking capacity is what protects the busbar from experiencing the catastrophic arc flash I posted earlier. I think.

The term rupturing capacity is applicable only for a device like a circuit breaker which can open a line during a fault.Bus bars have short circuit withstand capacity which ensure they don't melt before the breaker interrupts the fault current

Thank you for this clarity. I had the same impression Lyn had. I have seen busbars arc in the way that Lyn's pic showed. But not because of a simple ground or other circuit fault.

The first was at about the instant of meltdown of an entire substation. It didn't QUITE look as tame as Lyn's picture, though. It was accompanied by explosion, arc-flashes everywhere, ruptured transformer housing on it's outskirts, lots of glass slag left in the desert sand where it happened. It was caused by a direct lightning hit on station, and I was looking right at it when it happened. About 10 years old, so about 50 years ago. But I still have a vivid mental image, and a LOVE of lightning, explosions, arcs, and all such phenomena, as a result.

The second really big one was when flooding due to a Super Typhoon in Guam (May, 1976, Typhoon named Pamela) overwhelmed our power system in the comm building at ComNavWestPac, while the systems were still up. Full load on the building was somewhere around 40-50MW, and we used a Cat and a Waukesha genset as backups for the main power, which had already failed. But Navy Comms had to stay up and functional as long as possible, so while the building was being shutdown in an orderly manner (already secured the posits in the basement, more for the safety of the operators than for the equipment, which wound up submerged anyway) the gensets got "swept over" when the water crested the containment walls outside. I only say this in the aftermath, being a MatRat (the guys who had a finger in every part of repair and maintenance on the site, but in this case, AFTER the event, while we were trying to salvage what could be) and married (so I spent the duration of the storm at home caring for my family, while the single folks checked in to work, and kept things running. Shoot, THEY were safer than we were, given the sheer mass and structure of the concrete building they were in!).

Anyway, with about 2/3rds load still on the building (from what we were told) the gensets went out rather tamely, but the switchgear made up for it in sheer showmanship! It was a slag heap!

Ruptured, indeed!

It means the overcurrent protection devices are inappropriately too large, for these should operate before the busbar ruptures.