Panel board (1 out of 3)

[Mostafa Noah]

I want to know more details about a panel board which has No.3 incomer circuit breaker fed from (2 Normal feeders + 1 Emergency feeder) ?

The panel configuration shall guarantee the following :

• In case of normal operation, C.B No.1 (ON) ? C.B No.2 (OFF) ? C.B No.3 (OFF).
• If power failure occurred to supply No.1 (normal), C.B No.1 (OFF) ? C.B No.2 (ON) ? C.B No.3 (OFF).
• In case of the Power failure of the 2 mains (Normal), then the emergency C.B shall be ON, but only a certain Number of branch circuits shall be supplied; nearly (1/3) of the total number of outgoings branch circuits protected my miniature circuit breakers.

In case of using power controller similar to ABB's [Ekip Power Controller], is it possible to control miniture circuit breakers "outgoings" in case of the emergency case ?

 

[fmtjfw]

I want to know more details about a panel board which has No.3 incomer circuit breaker fed from (2 Normal feeders + 1 Emergency feeder) ?

The panel configuration shall guarantee the following :

• In case of normal operation, C.B No.1 (ON) ? C.B No.2 (OFF) ? C.B No.3 (OFF).
• If power failure occurred to supply No.1 (normal), C.B No.1 (OFF) ? C.B No.2 (ON) ? C.B No.3 (OFF).
• In case of the Power failure of the 2 mains (Normal), then the emergency C.B shall be ON, but only a certain Number of branch circuits shall be supplied; nearly (1/3) of the total number of outgoings branch circuits protected my miniature circuit breakers.

In case of using power controller similar to ABB's [Ekip Power Controller], is it possible to control miniture circuit breakers "outgoings" in case of the emergency case ?

1) How are you making sure only 1 of the three input breakers can be closed at a given time?
2) If there is some way to tell if CB #3 is closed (and I don't know how to do that without axillary contacts on CB #3) and if the load (output) breakers have shunt trip coils, then closing CB #3 could trip them off.

Here with such a requirement we would probably use 2 Automatic Transfer Switches and two panel boards.

ATS #1 would take input from the sources to CB #1 and CB #2.
ATS #2 would take input from the output of ATS #1 and from the source to CB #3.
ATS #2 would need a longer delay before transferring than ATS #1 so that ATS #2 would wait on CB #2's source to be tried.
The output of ATS #1 would feed a panel board that contained the loads that were to be supplied only when CB #1 or CB #2 is supplying power.
The output of ATS #2 would feed a second panel board that would feed only the loads to be supplied when CB #1, CB #2, or CB #3 is supplying power.

Hope this helps.

 

[Mostafa Noah]

Thank you for your reply, Theoretically I agree 100% with you, But it seems to me unpractical to install 2 ATS?s and 2 panels to get this function, it will be very expensive.

My point of view, was if the three power supplies are connected on the same busbar & must not operate in parallel (mechanically interlocked) & a power controller is equipped with the emergency circuit breaker, so, when the emergency C.B is ON, it should disconnect some ?predetermined- loads.

I don?t know either my point of view is feasible or no, especially when it comes to miniature circuit breakers outgoings ?

 

[augie47]

There are at least three problems associated with the ability to have more than one breaker "on" at a given time. The first is backfeeding. If two (or three) of your breakers are tuned on at the same time power from your panel could also flow back to the source of the other feeds allowing them to be energized even if the main to those respective panels was turned off. Secondly, the buss in your panel, being fed by two or three supplies could easily be overloaded and thirdly your panel would not have a singular point to disconnect power.