Breaker coordination

[francis.key19]

Hello,

We are trying to standardize control panels for all of our equipment and plant. Due to various loads on each equipment, we are looking to build panels with say 400 A main disconnect build into each panel. We would then only populate these panels depending number of contactors and load demands (meaning the ultimate load will be 300A or less). Is there any issues any one can see with this setup.?

Since these panels are remote from our MCC or switch gear room (about 120-300ft), we would add a breaker ahead of each panel sized for the actual load. This means that the remote breaker will trip before the one on the panel will (in the case of overload).

Does the code allows this?

Thanks.

Francis Key.

 

[jim dungar]

Does the code allows this?

Yes.

Coordination is an NEC requirement only for some hospital, emergency, and elevator circuits.
But because your system is really just two protective devices in series, coordination is a complete non issue. The down stream device is in effect acting as a local disconnect only.

 

[templdl]

Hello,

We are trying to standardize control panels for all of our equipment and plant. Due to various loads on each equipment, we are looking to build panels with say 400 A main disconnect build into each panel. We would then only populate these panels depending number of contactors and load demands (meaning the ultimate load will be 300A or less). Is there any issues any one can see with this setup.?

Since these panels are remote from our MCC or switch gear room (about 120-300ft), we would add a breaker ahead of each panel sized for the actual load. This means that the remote breaker will trip before the one on the panel will (in the case of overload).

Does the code allows this?

Thanks.

Francis Key.

Breakers protect cable. As long as your cable is sized to carry the load and the breaker is sized to protect the cable all that you need to consider is to compare the breaker trip curves for coordination for what you have described.
Other than a verbal description which is often subject to misinterpretation or interpreted differently by many it would be extremely helpful should you attach a one line of your proposed design.
We may assume something and/or you may assume some things that may end up to be entirely incorrect.
It sounds like something that should be considered though.