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DNO Tails on ladder

Apostolos
Good morning

I have a big student accomodation building with a dedicated DNO substation and a nearby LV switchroom where the DNO will place the cut-out ACB (1250A)

On the opposite wall we are putting our Main Distribution Panel.

Now, usually in previous cases the DNO cut out and the MDP panel are side by side and the tails go into a trunking.

In this case they will go on a ladder. From the DNO cut out box up to the ceiling, across the room and down to the MDP panel.

I know that ladder does not offer mechanical protection.

Can I still go with tails on the ladder? Or I need XLPE/SWA single cores in this case?

Is there something in BS7671 that prohibits the use of double insulated tails on a ladder?


Sorry for my ignorance

Kind Regards
Parents
  • 0
    I have never seen plain insulated and sheathed tails of any length on a cable ladder.  I don't see why you couldn't use them provided you take steps to protect them mechanically from damage during installation and from subsequent maintenance activities. They will need suitable support and restraint all the way.  Can you actually get the larger sizes in quantities you need.  You would also need to check the mechanical properties of the cable.  I suspect that they will sag a lot more than AWA etc and this will put extra pressure on the sheath/insulation at the support points. You might need extra rungs on the ladder to support them.  It might even be difficult to get a decent trefoil.  You would need to find cleats designed for the softer sheath.


    Why are you considering this sort of cable?  It is certainly an unconventional approach which may well raise questions that could be difficult to answer.  Have a look at the recent thread on theatre cabling.
Reply
  • 0
    I have never seen plain insulated and sheathed tails of any length on a cable ladder.  I don't see why you couldn't use them provided you take steps to protect them mechanically from damage during installation and from subsequent maintenance activities. They will need suitable support and restraint all the way.  Can you actually get the larger sizes in quantities you need.  You would also need to check the mechanical properties of the cable.  I suspect that they will sag a lot more than AWA etc and this will put extra pressure on the sheath/insulation at the support points. You might need extra rungs on the ladder to support them.  It might even be difficult to get a decent trefoil.  You would need to find cleats designed for the softer sheath.


    Why are you considering this sort of cable?  It is certainly an unconventional approach which may well raise questions that could be difficult to answer.  Have a look at the recent thread on theatre cabling.
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