I do appologize guys,
I cut and pasted the incorrect document, was distracted and then didn't review my post and clicked send and turned off the computer for the evening.
The following is what I intended to post on series rated breakers:
I have always understood that you first must establish the KAIC available at the service entrance which is commonly provide by the power company. The disconnects, i.e., the Main breaker, must be rated with a minimum kaic of the available fault current. With fully rated systems all otehr devices must be also.
However, in that main panel the feeder and/or branch devices may have ratings that are considerably less than the main device, that is if these devices have been series rated with the main breaker. What the manufacturer has done is to test the main breaker with the downstream devices to assure that the main breakers current limiting capability (not necessarily a "current limiting" circuit breaker) will be current limiting enough to protect those down stream breakers from a fault current that could damage them.
However, the manufacturer simply cannot make this determination but the combination must pass UL tests and be listed as such. Thus, this panel is considered to be series rated. Likewise, down stream panels and breakers can be series rated with those that are upstream provided that they, too, have been tested and listed by UL to be applied as such. Manufacturers will have a table of some sort which shows which breakers can be used is series with others.
One thing that must be noted is that you cannot mix manufacturers products unless they too have been tested and listed with one another which is not likely. But quite often fuses may be tested and series rated with breakers by some manufacturers.
One of the goals of using series rated devices is to reduce the cost of the installation by using less expensive OCPDs. I'm sure you're well aware of the premium that must be paid for higher kaic devices. The manufacturers make you dig deep in your pocket for those 65 and 100kaic breakers.
When a spec. hasn't disallowed series rated breakers then they would be allowed. I have been able to reduce my proposal price significantly by using series rated devices in lieu of fully rated devices..
Also, "physically thermal magnetic" breakers are very hard to coordinate at best. These are non-electronic trip type breakers.
They will almost all certainly coordinate thermally (overload) but magnetically (fault, instantaneous)it is often pot luck which breaker in series with the other will trip when all see the same fault if the magnetude of the fault is within that calibration of those breakers. There is no coordination.
Neither series rated nor 100% rated breakers provide any advantage in the coordination in this regard as they all have the same trip calibrations. Being that 100% rated breaker have electronic trip units those have adjustable pick-ups and delays (LI, LSI, LSIG) can provide a level of coordination when set properly. Some even will communicate with one another letting each other know that they see the fault allowing the upstrean breaker to delay giving the down stream breaker the time to trip first.
