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Cable routing/eddy currentso

Baldyhugh
Hi


I have a query regarding a cable route for  a job I’m currently on (when lockdown rules allow me back to it!). I have to supply a feed motor on a farm, the contactor feeding it is at one end of the building in a plant room. There is an existing steel trunking running the length of the building and I plan to come out of this close to the motor with pvc conduit. However there is a paddle switch in the meal hopper beside the motor that will control the contactor. This needs a simple two wire connection. My question is can I run these two cables out of the trunking in the same conduit as the cables to the motor. I plan to put a wiska box or similar at the other end of the conduit so that I can split off to the motor and paddle switch separately, and there will be an isolator before the motor. 

The question however remains regarding the ‘control cables’ in the same conduit as the motor supply. They are from the same circuit and the same voltage but was concerned about eddy currents. 

Thanks in advance
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  • 0
    There sometimes is a possible benefit from having earths from both circuits connected.


    1/ Effective R2 reduced as via parallel paths on at least some of the earth path.

    2/ Redundancy - a break in cpc somewhere on one circuit might possibly be mitigated to some extent.


    On domestic rewires I tend to link all the earths on lighting circuits and that is usually acheived on two way lighting - ganging switches so at least two circuits present in switch backbox , often at stairway lighting. Of course anyone woprking on such switches would need to isolate two or more circuits before proceeding into the switchbox (We all always isolate before opening up dont we? ? )


    PS - One thing to note - any R2 testing must be done on each circuit separately to omit para paths to prove integrity of each circuit E
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  • 0
    There sometimes is a possible benefit from having earths from both circuits connected.


    1/ Effective R2 reduced as via parallel paths on at least some of the earth path.

    2/ Redundancy - a break in cpc somewhere on one circuit might possibly be mitigated to some extent.


    On domestic rewires I tend to link all the earths on lighting circuits and that is usually acheived on two way lighting - ganging switches so at least two circuits present in switch backbox , often at stairway lighting. Of course anyone woprking on such switches would need to isolate two or more circuits before proceeding into the switchbox (We all always isolate before opening up dont we? ? )


    PS - One thing to note - any R2 testing must be done on each circuit separately to omit para paths to prove integrity of each circuit E
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