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Band I / Band II cct separation

Farmboy
Does the principal of Band I / Band II  cct separation re 528.1 apply within equipment? A DETA mechanical chime with internal transformer has LV and ELV wiring right near each other within the same enclosure (the lid of which is easily removable without tools), which seems to moot the requirement to have them separated as per the reg?


F
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    Jaymack:




    tattyinengland:

    Well consider a motor control centre where voltages of any size may be present. The controls from automation equipment and telemetry are likely to be present and cables carry no volts at all are common monitoring whether a contactor is open or closed for example. 

     



    An MCC would probably be an industrial or commercial application. BS 7671 wouldn't apply in that case, i.e. above 100 Amps.


    Jaymack 

     




    I'm not sure about the rationale of 100 A being a cutoff for BS 7671 - it's definitely only on voltage range; however, BS 7671 does not apply to pre-manufactured assemblies which are to comply with appropriate standards.


    If the component were pre-manufactured into the unit, the selection and fitting of the component, and any wiring connected during manufacture of the panel, would, I agree, be covered under BS EN 60204-1 and/or BS EN 61439-series as appropriate. Selection and installation of the panel, if within the voltage range of BS 7671, is within the scope of BS 7671.


    BUT, installations of cables brought in from outside the enclosure on-site are covered by BS 7671 if they are LV or ELV, so it's likely an external comms cable, as with the other connecting cables of the assembly, would be within the scope of BS 7671.


    I've worked on many MCCs that are installed wholly (both input and output are LV, and controls/comms are ELV) or partly (input and/or output HV, but LV and ELV components and controls are connected) within the scope of BS 7671.

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    Jaymack:




    tattyinengland:

    Well consider a motor control centre where voltages of any size may be present. The controls from automation equipment and telemetry are likely to be present and cables carry no volts at all are common monitoring whether a contactor is open or closed for example. 

     



    An MCC would probably be an industrial or commercial application. BS 7671 wouldn't apply in that case, i.e. above 100 Amps.


    Jaymack 

     




    I'm not sure about the rationale of 100 A being a cutoff for BS 7671 - it's definitely only on voltage range; however, BS 7671 does not apply to pre-manufactured assemblies which are to comply with appropriate standards.


    If the component were pre-manufactured into the unit, the selection and fitting of the component, and any wiring connected during manufacture of the panel, would, I agree, be covered under BS EN 60204-1 and/or BS EN 61439-series as appropriate. Selection and installation of the panel, if within the voltage range of BS 7671, is within the scope of BS 7671.


    BUT, installations of cables brought in from outside the enclosure on-site are covered by BS 7671 if they are LV or ELV, so it's likely an external comms cable, as with the other connecting cables of the assembly, would be within the scope of BS 7671.


    I've worked on many MCCs that are installed wholly (both input and output are LV, and controls/comms are ELV) or partly (input and/or output HV, but LV and ELV components and controls are connected) within the scope of BS 7671.

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