Ethernet in a MCC raceway.

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Montana

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What I have is an Allen-Bradley MCC with Power Flex variable speed drives. I would like to communicate with these drives via 20-COM-E modules. This would require putting CAT-5 in the raceways with the motor leads. The motor leads are rate for 600V and the CAT-5 is only rated for 300V. I?ve done a bunch of searches and read a bunch of threads and I still can?t figure out if this is acceptable. Any help would be greatly appreciated.
 

Montana

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In my searches I came across a thread called, ?Devicenet Cables within the same Wireway as 600 Volt motor powerwires? This thread address a lot of similar issues.
 

Montana

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In my searches I came across a thread called, “Devicenet Cables within the same Wireway as 600 Volt motor powerwires” This thread address a lot of similar issues.
 

don_resqcapt19

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retired electrician
Just put a length of flexible metal conduit in the MCC wireway and install the Ethernet in the flex.
I don't really think fiber is a real option here. The communications is being run to multiple buckets in the MCC. There is not likely enough space for the media converters and their power supplies.
 

don_resqcapt19

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retired electrician
091119-1922 EST

Montana:

Consider Ethernet to fiber and run the fiber with the high voltage. Even if you had high voltage Ethernet cable I would be concerned with noise problems.


The construction of the Ethernet cable does a lot to protect it from the "noise". I am aware of a number of installations with standard Ethernet cable in the MCC wireways for PLC control of the equipment and I have heard of any noise issues.
 

gar

Senior Member
091120-0914 EST

Don:

Your information is useful because it relates a similar application.

Ethernet cables use twisted pairs. This greatly reduces magnetic coupling of noise to the balanced signal lines. They also use different pitches of the twist for the four different pairs to reduce crosstalk.

In crude uncontrolled experiments I have run with Ethernet communication with CAT-5 cable using a MIG welder as the noise source I found degradation of the signal, meaning retries, when the CAT-5 cable was in the range of about 3 to 4 ft of the MIG welder cables.

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Montana

Member
Thanks to all of you. It?s nice to have a place to post a question to experts in the field. I can?t even imagine the years of experience that went into these replies. I can see this is a gray area that the NEC needs to address. Again thanks for all the replies.

Some where in Montana
 
Thanks to all of you. It?s nice to have a place to post a question to experts in the field. I can?t even imagine the years of experience that went into these replies. I can see this is a gray area that the NEC needs to address. Again thanks for all the replies.

Some where in Montana

Actually the NEC had already addressed it. It claims no authority inside electrical equipment.
 
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