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TN ring mains in hospital theatres

MS01
Is there any issue with installing a TN ring circuit in hospital operating theatre?


I appreciate Medical IT circuits are in a radial wiring pattern and ultimately any medical equipment is plugged into these circuits, but i'm talking about the 2  /3 TSSO's in the space that are for PC use?  


Within BS 7671 clause 710.415.2.3 which talks about earthing there is a note which states:- It is recommended that radial wiring patterns are used to avoid ‘earth loops’ that may exacerbate electromagnetic disturbances.


My question is do these TN circuits need to follow this radial pattern or can ring mains be installed? 


Matt
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    I must say, as one who worries about EMC and earth loops a lot, I find that advice a bit surprising. Only a defective ring final is going to generate or respond to magnetic fields more than a radial.

    The thing that really throws the earth currents off kilter is providing parallel paths that do not follow the same route as the L and N currents. This occurs everywhere we bond to any already earthed object for example  at a water heater with a metal feed pipe, or a socket box that attaches also to structural steels.

    IF there really is an EMC problem, the advice must be to avoid these cases  too, but in fact they are not only not prohibited, but in effect mandated.


    A radial will be fine, but don't make EMC the reason not to use a ring.  I presume whoever offers the advice  has not actually measured the fields around a ring.
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  • 0
    I must say, as one who worries about EMC and earth loops a lot, I find that advice a bit surprising. Only a defective ring final is going to generate or respond to magnetic fields more than a radial.

    The thing that really throws the earth currents off kilter is providing parallel paths that do not follow the same route as the L and N currents. This occurs everywhere we bond to any already earthed object for example  at a water heater with a metal feed pipe, or a socket box that attaches also to structural steels.

    IF there really is an EMC problem, the advice must be to avoid these cases  too, but in fact they are not only not prohibited, but in effect mandated.


    A radial will be fine, but don't make EMC the reason not to use a ring.  I presume whoever offers the advice  has not actually measured the fields around a ring.
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