PDU wiring diagram

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New EE

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California
Can someone tell me if I'm showing this wiring diagram correctly for a power distribution unit (PDU). It's a PDU with two seperate sources coming off seperate distribution panels. The PDU has a Kirk key interlock along with an isolation transformer and two 42 pole panelboards all within the PDU. Thanks.
 

Jraef

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Kirk-Key interlocks are usually depicted as just a box with circle in it off of each breaker, then a note describing the interlock logic (there are many forms available). If it's a one key system (most common), then you show a slash in one and not the other.

Like this.
Interlock%20System%20Diagram.gif
 

kingpb

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SE USA as far as you can go
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Engineer, Registered
Can someone tell me if I'm showing this wiring diagram correctly for a power distribution unit (PDU). It's a PDU with two separate sources coming off separate distribution panels. The PDU has a Kirk key interlock along with an isolation transformer and two 42 pole panelboards all within the PDU. Thanks.

Just put a K in the box, that's all I would need to see. If you put a E, that would mean electrically interlocked. You would need a description somewhere that says you don't want them closed at the same time, or whatever the requirement is.
 

Mike01

Senior Member
Location
MidWest
Kirk-Key / Xfmr Secondaries

Kirk-Key / Xfmr Secondaries


Barclayd, posted a great link for the kirkkeying of the devices you can refer to his post (quoted), however in your sketch using a kirk-key setup you actually have two kirk key locations and only one key, the closed holds the key captive and will not be released until the breaker is in the "off" position at that time you can remove the key and insert it into the other location once engaged turn that breaker "on" locking the key keeping it capitve at that location. Another question about your sketch, you have a transformer (I am assuming a three phase four wire secondary) I also assume the breakers you are indicating in the panels are main circuit breakers? You show a feeder on the transformer secondary and that secondary being "tapped" to two different panels you may want to look at the code as it relates to transformer overcurrent protection and tapping transformer secondary conductors, you may have to run two feeders from the transformer secondary one to each panel?
 

ron

Senior Member
You show a feeder on the transformer secondary and that secondary being "tapped" to two different panels you may want to look at the code as it relates to transformer overcurrent protection and tapping transformer secondary conductors, you may have to run two feeders from the transformer secondary one to each panel?

Mike,
There are pre-fabbed PDU's that are listed, so they geenrally are not required to comply with the 450 rules in the NEC. Sometimes we have (6) breakers on the output from a common secondary feeder. PDI, Liebert, MGE, etc all provide this type of product.
 
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