Coordination Study for PLC Panel
Coordination Study for PLC Panel
(OP)
I have never been asked to do a coordination study on my PLC Control panel.
I'm using various amperage of the same Allen Bradley Breakers
1489-A1D020 - 2 Amp
1489-A1D030 - 3 Amp
1489-A1D050 - 5 Amp
1489-A1D200 - 20 Amp
These breakers feed power to I/O module,Power Supplies, and various transmitters in the field (Ultra Sonics, Flow Meters, Gas Analyzer).
The Engineer reviewing my Panel Drawings is requesting a coordination study for the breakers and main breaker in my panel that gets power from the distribution panel.
I would believe if a fault (Line-Ground) were to occur the branch circuit breaker that is experiencing the fault would trip first. None of these breakers have adjustable trip curves.
My response for the my Main breaker to the distribution panel would be for the Arc Flash firm who is doing all the calculation on new equipment.
Do these response have a case?
I'm using various amperage of the same Allen Bradley Breakers
1489-A1D020 - 2 Amp
1489-A1D030 - 3 Amp
1489-A1D050 - 5 Amp
1489-A1D200 - 20 Amp
These breakers feed power to I/O module,Power Supplies, and various transmitters in the field (Ultra Sonics, Flow Meters, Gas Analyzer).
The Engineer reviewing my Panel Drawings is requesting a coordination study for the breakers and main breaker in my panel that gets power from the distribution panel.
I would believe if a fault (Line-Ground) were to occur the branch circuit breaker that is experiencing the fault would trip first. None of these breakers have adjustable trip curves.
My response for the my Main breaker to the distribution panel would be for the Arc Flash firm who is doing all the calculation on new equipment.
Do these response have a case?






RE: Coordination Study for PLC Panel
RE: Coordination Study for PLC Panel
Side issue: You are either dealing with an older existing panel, or you are being sold old obsolete products. The 1489A series was supplanted by the 1489M series about 3 years ago. The original A series product is not RoHS compliant, so as of last year cannot be shipped into countries that require it. Because of this, many distributors that failed to return their stock to Rockwell after the change found out that they can't sell them, so they dumped them off onto the "gray market" of breaker brokers who cater to people that buy strictly on price, usually unaware of the possible negative consequences. So if this is new and you have not yet bought the breakers, you may want to change to the 1489M series, unless this is for your own consumption and you are in the US, who does not yet adhere to the RoHS rules. Everything else about them is the same in terms of ratings etc.
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: Coordination Study for PLC Panel
Is coordination even necessary at this low level? Typically the circuit breakers are in place to protect the wire/equipment.
Yes this is a new PLC control panel. Even if I switched to the 1489M series breaker will they coordinate well to prevent the Main Breaker from going off?
RE: Coordination Study for PLC Panel
RE: Coordination Study for PLC Panel
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: Coordination Study for PLC Panel
I am currently using an application 'Curve Direct' from Schneider Electric, but have used similar software from GE and AB which gives the same results.
In essence, you co-plot the trip curves of the devices that you are wanting to coordinate, and see how they plot in relation to each other.
If you have two curves that are separate and have a reasonable gap between them, then you have some assurance that they will coordinate. If there are zone(s) where the curves intersect of come very close, then you are not so certain.
Knowing just how much separation between curves is reasonable was, at least for me, a matter of asking some of the more experienced engineers for some guidance.
RE: Coordination Study for PLC Panel