# Proprietary 110.3(B)



## Going_Commando (Oct 1, 2011)

You have got to be kidding me. What happens if I install a 200 amp millbank meter/main then? Guess. I just have to put in square-D everything from now on to be on the supposed "safe side". This crap is getting out of control and soon we will probably have to be certified by e manufacturers to install devices and switchgear.


----------



## SteveBayshore (Apr 7, 2013)

Only in series combination systems. I have never instaled a series combination system, or even remember working on one.


----------



## BBQ (Nov 16, 2010)

Going_Commando said:


> You have got to be kidding me. What happens if I install a 200 amp millbank meter/main then? Guess. I just have to put in square-D everything from now on to be on the supposed "safe side". This crap is getting out of control and soon we will probably have to be certified by e manufacturers to install devices and switchgear.


It makes perfect sense when using a series of equipment to deal with high fault current levels. It is actully a way we can save money.


----------



## Fibes (Feb 18, 2010)

SteveBayshore said:


> Only in series combination systems. I have never instaled a series combination system, or even remember working on one.


Seems as though 90% of our larger sized jobs over the past 5 years have been series rated which includes coordination studies. New projects are not a problem because the gear will purchased and engineered from a single manufacturer. On large renovations it gets more involved since they typicallly have a number of different manufacturers equipment.


----------



## SteveBayshore (Apr 7, 2013)

BBQ said:


> It makes perfect sense when using a series of equipment to deal with high fault current levels. It is actully a way we can save money.


I use current limiting fuses in the main gear when installing projects with high fault current levels. It gets the rest of the system down to standard (economical) fault currents. I don't have to wory about customers "electricians" working in or replacing equipment after I leave.


----------



## Pete m. (Nov 19, 2011)

SteveBayshore said:


> I use current limiting fuses in the main gear when installing projects with high fault current levels. It gets the rest of the system down to standard (economical) fault currents. I don't have to wory about customers "electricians" working in or replacing equipment after I leave.


Depending on the equipment you are trying to protect a current limiting fuse may or may not provide any protection unless it has been tested for the function.

As far as I have researched a current limiting fuse can not be relied on to reduce the available fault current when installed ahead of MCCB's. Here again, the fuse may provide some protection but only if part of a tested and listed combination.

Pete


----------



## Semi-Ret Electrician (Nov 10, 2011)

We've all installed "series rated" equipment at one time or other, even if we didn't take advantage of it.

I always look for 22Kaic main breaker/branch circuit combinations even if the standard 10K stuff will work. Why not? It's a better install, usually doesn't cost any more and even Home Depot shelves are filled with them.


----------

