Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Suggested Answer
  • Replies 6 replies
  • Helpful Answers 1 Helpful answer
  • Subscribers 19 subscribers
  • Views 154 views
  • Users 0 members are here
Options
You may also be interested in

Metal cable tray regulations

Tomas Korytar

Good morning,

Could anyone advise on the containment separation requirements for metal trays? I’ve been trying to find specific regulations or guidance on separation distances between LV and ELV cable trays, but haven’t been able to locate anything definitive. Does a standard or code require a minimum separation, segregation method, or specific containment practice for metal trays carrying LV vs ELV?

Any references to relevant standards or practical guidance would be greatly appreciated.

Parents
  • 0

    I'm not sure I'd think of tray as "containment" as such - more just cable support. Unlike say conduit or trunking cables on tray should be sheathed, so voltage-wise they should be safe to touch (or be touched by sheathed cables of other circuits). There are other considerations though - e.g. preventing interference. I can't think of any specific separation distances for above ground situations in BS 7671 (but there may be some in related standards, depending on quite what the ELV circuits are - e.g. data/comms cables and the type of cables). In any case the required separation would typically be between cables themselves, rather than the trays they're on. 528.1 (iv) does seem to permit Band I and Band II cables to share the same tray provided they're physically separated by a partition (but again other standards may ask for more).

       - Andy.

Reply
  • 0

    I'm not sure I'd think of tray as "containment" as such - more just cable support. Unlike say conduit or trunking cables on tray should be sheathed, so voltage-wise they should be safe to touch (or be touched by sheathed cables of other circuits). There are other considerations though - e.g. preventing interference. I can't think of any specific separation distances for above ground situations in BS 7671 (but there may be some in related standards, depending on quite what the ELV circuits are - e.g. data/comms cables and the type of cables). In any case the required separation would typically be between cables themselves, rather than the trays they're on. 528.1 (iv) does seem to permit Band I and Band II cables to share the same tray provided they're physically separated by a partition (but again other standards may ask for more).

       - Andy.

Children
  • 0 in reply to AJJewsbury

    Thank you, AJJewsbury, for your valuable input as well. You make a valid point that cable trays could be regarded more as a means of cable support rather than full containment. However, I would still tend to classify them as a form of containment unless regulations explicitly state otherwise.
    My understanding is that when cables are installed in separate trays, this provides a degree of mechanical segregation that also helps to reduce electromagnetic interference. This follows the same principle as using a divider within a single tray to separate LV and ELV circuits.
    I have also reviewed BS 6701 and could not find any specific references to cable trays in this context.

Community Rules & Guidelines