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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
    Well two caveats to add first:


    1) I don't do HV

    2) I'm just a spark (Not a design engineer)


    We've just done something similar for a supply to a Railway station (West London) and had 900mm ladder rack suspended from a basement ceiling, 40 odd meters, onto which the HV lads have run in their HV cables (Big fat Red ones). Similar size of supply assuming you're talking of the LV size. 


    I have no idea if they are armoured or not (But the induced voltages in the ladder rack would be pretty bad if they weren't, so I suspect they are) but the whole ladder rack thing certainly works for all concerned in our situation.


    I suspect it will for your situation too.


    Another thought - Do Check with the HV chaps - The bonding of the ladder rack may be an HV requirement (no idea; I'm pretty sure the HV guys sorted out their earthing and bonding) and quite how the earthing divisions between LV and HV might integrate - or not - and work
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  • 0
    Well two caveats to add first:


    1) I don't do HV

    2) I'm just a spark (Not a design engineer)


    We've just done something similar for a supply to a Railway station (West London) and had 900mm ladder rack suspended from a basement ceiling, 40 odd meters, onto which the HV lads have run in their HV cables (Big fat Red ones). Similar size of supply assuming you're talking of the LV size. 


    I have no idea if they are armoured or not (But the induced voltages in the ladder rack would be pretty bad if they weren't, so I suspect they are) but the whole ladder rack thing certainly works for all concerned in our situation.


    I suspect it will for your situation too.


    Another thought - Do Check with the HV chaps - The bonding of the ladder rack may be an HV requirement (no idea; I'm pretty sure the HV guys sorted out their earthing and bonding) and quite how the earthing divisions between LV and HV might integrate - or not - and work
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