Instrumentation and power separation

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Pok3r

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Is there a code or requirements of communication separation other than Article 300. I have and MCC with communication and power running in the same cable tray. I know the NEC doesn't care if the system fails, but is there a reference or guide line for communication and power cabling?


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Thank you, Yes 725.51 c show 725.121 Power Sources for Class 2 and Class 3 Circuits. (A) Power Source. The power source for a Class 2 or a Class 3 circuit shall be as specified in 725.121(A)(1), (A)(2), (A)(3), (A)(4), or (A)(5):

FPN No. 1: Figure 725.121 illustrates the relationships be- tween Class 2 or Class 3 power sources, their supply, and the Class 2 or Class 3 circuits.

FPN No. 2: Table 11(A) and Table 11(B) in Chapter 9 provide the requirements for listed Class 2 and Class 3 power sources.

(1) A listed Class 2 or Class 3 transformer (2) A listed Class 2 or Class 3 power supply (3) Other listed equipment marked to identify the Class 2 or Class 3 power source

Exception No. 1 to (3): Thermocouples shall not require listing as a Class 2 power source



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Pok3r said:
Am still confuse
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It's not rocket science... it's actually worse. :lol:

Kidding aside, power to one side of tray, control to the other, physical barrier (divider) in between. If you also have communications cables, three sections, two dividers.
 
6779a0187c5ee6e2fd83adb12e3c5ebd.jpg
is this a violation for you.. it inside an mcc and there is 480 mix with controls wiring inside the panel if so can you tell me where i can find it


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Pok3r said:
... is this a violation for you.. it inside an mcc and there is 480 mix with controls wiring inside the panel if so can you tell me where i can find it
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BTW that's not cable tray as defined by the NEC. That's wiring duct.
http://www.panduit.com/en/products-...routing-protection-and-insulation/wiring-duct

The NEC offers some restriction on separation inside enclosures, but it far from ideal. Perhaps take a look at NFPA 79 Electrical Standard for Industrial Machinery
http://www.nfpa.org/codes-and-stand...ds/list-of-codes-and-standards/detail?code=79
 
That application may fall under UL 508A, if its a control panel.
I run control and signaling in that type of duct together with power wiring, but only 120V. Never 480
 
tom baker said:
That application may fall under UL 508A, if its a control panel.
I run control and signaling in that type of duct together with power wiring, but only 120V. Never 480
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It is my understanding that UL508 does not apply to field wiring... unless that field wiring is between panels or equipment and furnished by the manufacturer as part of the listed product. I believe NFPA 79 says the same thing.
 
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