MCCB in main switchgear

[m sleem]

It's a good practise to have drawable air breakers in switchgear, but the contractor raised a valid question "for small loads e.g. 250a why drawable ACB & not drawable MCCB?"

 

[kingpb]

For LV Switchgear, I would use whatever meets the project requirements and is rated for the intended purpose.

If the equipment is specified that way, there may be an operational or maintenance reason for it. Check with the original specifier. If there is nothing that dictates a certain type of equipment, go with whatever is the cheapest.

The term, " well, we've always done it that way" may very well come up.:weeping:

 

[ron]

The only company that makes a draw-out molded case CB that I know of in the US is Eaton, and it is pretty cheesy. I think it only fits in SWBD's.

I don't think any MCCB is listed to go along with SWGR.

From http://apps.geindustrial.com/publibrary/checkout/APPLICATION?TNR=White Papers|APPLICATION|generic

Switchgear and switchboard structures are built and tested to different standards: Switchgear
to ANSI standard C37.20.1, UL standard 1558, and NEMA standard SG-5, switchboards to NEMA
PB-2, and UL-891. Switchgear incorporates only low-voltage power circuit breakers (LVPCB)
which conform with ANSI C37.13, NEMA SG-3 and are listed per UL-1066, whereas
switchboards may include any combination of protective devices including insulated case
(ICCB), molded-case circuit breakers (MCCB) listed per UL-489, fusible switches listed per UL-508
and 977 and power circuit breakers listed to UL-1066.

 

[kingpb]

The only company that makes a draw-out molded case CB that I know of in the US is Eaton, and it is pretty cheesy. I think it only fits in SWBD's.

I don't think any MCCB is listed to go along with SWGR.

From http://apps.geindustrial.com/publibrary/checkout/APPLICATION?TNR=White Papers|APPLICATION|generic

Switchgear and switchboard structures are built and tested to different standards: Switchgear
to ANSI standard C37.20.1, UL standard 1558, and NEMA standard SG-5, switchboards to NEMA
PB-2, and UL-891. Switchgear incorporates only low-voltage power circuit breakers (LVPCB)
which conform with ANSI C37.13, NEMA SG-3 and are listed per UL-1066, whereas
switchboards may include any combination of protective devices including insulated case
(ICCB), molded-case circuit breakers (MCCB) listed per UL-489, fusible switches listed per UL-508
and 977 and power circuit breakers listed to UL-1066.

Ron, good info for USA, but I was basing my comment on the fact the person listed location as Cairo, so I am assuming IEC equipment. Completely different offerings available for LV switchgear, which in IEC world includes a large assortment including what we would call MCC's.

 

[Jraef]

Ron, good info for USA, but I was basing my comment on the fact the person listed location as Cairo, so I am assuming IEC equipment. Completely different offerings available for LV switchgear, which in IEC world includes a large assortment including what we would call MCC's.

LOL, you have made an assumption there...

Cairo, Georgia, United States
Cairo, Illinois, United States
Cairo Township, Minnesota, United States
Cairo, Missouri, United States
Cairo, Nebraska, United States
Cairo, New York, United States
Cairo, Ohio, United States
Cairo, West Virginia, United States

I have to admit, I was only aware of Cairo, GA because I visited there once, but it turned out there are a bunch more.

I also recently did a project in Bagdad... Arizona
(Yes, I know the spelling is different)
My wife FREAKED when I told her...

 

[m sleem]

Ron, good info for USA, but I was basing my comment on the fact the person listed location as Cairo, so I am assuming IEC equipment. Completely different offerings available for LV switchgear, which in IEC world includes a large assortment including what we would call MCC's.

You'r 100% correct, i'm from egypt & accordingly following IEC, but i'm refering to a project in KSA has US specs.