ACB Vs MCCB type Disconnector Switches

[NickParker]

How do you differentiate between ACB type isolators Vs MCCB type isolators? as both are mentioned as "Disconnector Switch" or "Isolators" in the drawing.

Using ACB type isolators without Electronic trip unit or releases.
Using MCCB type isolators without Electronic trip unit or releases.

 

[jraef]

ACBs are designed to be serviced and rebuilt, MCCBs are not. As an isolator it likely wouldn’t be damaged unless there was a fault, but if that happened, the MCCB would have to be discarded, whereas the ACB could be repaired. I’m not sure how important that would be to someone, I’m just pointing out the major difference in the device technologies.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[che12345]

NickParker (Electrical)(OP)23 Sep 24 14:01
' How do you differentiate between ACB type isolators Vs MCCB type isolators? as both are mentioned as "Disconnector Switch" or "Isolators" in the drawing'.
I have the following opinion for your consideration.
1. Both are "disconnector switch" or "isolator" as both fulfilled:
a) the contacts/poles distance in open state passed the impulse voltage (usually 8 kV of LV).
b) they can be switched from closed to open position (usually manually) with load or during starting of motor.
Attention: Some "isolators" are designed to switch without voltage !
c) they shall be provision for locking in open position (usually with extra mechanism by OEM) which shall be attached on the breaker [not on the door]; which can be opened with the breaker closed.
2. ACBs are heavier built, more costly and bigger in size than MCCMs.
3. ACBs usually are rated Icu x kA for 1 s, where MCCBs have no Icu or have very low Icu for 1 s. BTW: this differences may not be the criterial in this application.
Che Kuan Yau (Singapore)