Enclosing AB network cables in conduit

Hi,

We currently install SLC racks that use Belden (Blue hose) cable for DH+ communication between processors. We also use the same cable for 1747-SN scanner cards to communicate with remote flex I/O modules installed in machines. To date I have avoided running these communication (blue hose) cables near contol and power cabling. We install the communication cables on the outside fencing of our automated cells. My question is can these communication cables be installed in conduit or placed in wire tray with other control/power conductors? This would be for mechanical protection reasons aswell as for visual appearance when several cables are routed around an automated cell. My concern if running the cables in conduit is an enclosed metal field around the blue hose. If run in wire tray with power/control cables interferance in signals transmitted from magnetic fields.

Thank you
Derick

from my standpoint, this is a no-no. Never run comm cables along with transmission (power/control) wiring. The electrical noise will wreak havoc on communications. In the US, the National Electrical Code says you can run different voltages in the same raceway IF all wiring shares the same insulation class (i.e., if they are all MTW, or all THHN,etc...). Since the Belden cables have a different insulation than that of field wiring, then the answer is no. Inside panels,like in panduit, you can eliminate the noise by grounding one side of the shield. But panels aren't the same as conduit where space is more constricted. Run all comm cables in it's own conduit...

Dedicated conduits are normally used for communciations, or a ferrous cable tray divider to separate the power wiring from communications.

I always segregate the blue hose and also run it in steel conduit for both protection and interferance points of view.

I agree with all of the responses though in real practice I've seen "blue hose" run with power and I/O more often than not.

jstolaruk said:

I agree with all of the responses though in real practice I've seen "blue hose" run with power and I/O more often than not.

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Blue Hose run on cable tray with 400 volt power and some invertor cables - seen it as well and dh+ ran fine

we run all our blue hose in cable trays. 2 sides, high voltage 600 and low voltage 120, 24 and blue hose... never had a problem in the 7+ years these cells have been running...knock on wood.

Good practice dictates that signal be run separately from power. I'd be interested in hereing what Rockwell Automation recommends. If you do run it in the cable tray with power and in the future random glitches start appearing, they will blame it on the most obvious cause even if it is not the root cause.

I run blue hose with low voltagae DC all the time, no problems. Never tried any other combination.

One of those "your mileage will vary" things

Best practice is to keep the blue hose separated from high voltage cabling and when crossing, do so perpendicularly.

I recall a DH installation from about 25 years ago where the blue hose was clipped against a concrete wall with no additional protection (like conduit). There were a number of intermittent problems. The theorising was that earth currents in the concrete's reinforcing steel was the culprit and when the blue hose was moved away from the wall the problems disappeared.

Go figure. You live and learn.

504bloke said:

Blue Hose run on cable tray with 400 volt power and some invertor cables - seen it as well and dh+ ran fine

Click to expand...

Unregistered said:

we run all our blue hose in cable trays. 2 sides, high voltage 600 and low voltage 120, 24 and blue hose... never had a problem in the 7+ years these cells have been running...knock on wood.

Click to expand...

cable trays are the exception...the original poster asked about conduit, and tray isn't conduit.In a tray, the noise isn't restricted to a small area surrounding the transmission.

thanks!

My thanks to all the members that replied to the post. I was mostly concerned about installing the cable in conduit. Based on Stasis and Mgvol responses I will use a dedicted conduit for communication. Thank to to all the members that took the time to reply. I am finding this site to be an invaluable tool.

Derick123