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Cables installed behind cladding on commercial units

Declan A

Hi

I am acting as the electrical engineer for a project that is currently in RIBA Stage 5.

The design of said project was carried out by another M&E Consultant.

The project is essentially 5 x large commercial / retail units, a large car park and a communal area at the back for deliveries etc. All of the units are attached but are separate entities with their own incomer from the local substation.

The client has agreed with the tenant to provide lighting to all of the units which shall be maintained and paid for by the client (landlord).

The design currently proposes a circuit to be fed from the landlord supply in the communal area to supply the lighting on the units, with the cable for said circuit running behind the cladding of the retail units clipped to the steel structure using girder clips.

I have a few concerns with this and I don't think it is the correct way to do it.

However with this said I just wanted a second opinion before I raise the alarm so to speak.

Concerns:

1.) Cable is crossing multiple boundaries going from landlord area to tenant areas

2.) Tenants will be unaware of cable and even if they are will be unable to isolate it if they need to do some work that involves drilling through the cladding

3.) If a tenant was to isolate their unit at the incomer, they would still have a live cable running through their unit

4.) Maintenance access will require removal of the cladding on the retail unit

  • +1

    Is the cable adequately protected - conduit/SWA or similar, so that drilling is unlikely to be fatal, just embarrassing ?  In that regard, twin and earth or plastic tube with singles would be most concerning and steel conduit the least. 
    How far in from either surface, and how much do the heavier girders provide mechanical protection of the route ? Thinking short drill bits and screws.
    It would be better to have a visible route,  If yes to the above, then I'm not sure it breaks any regs, but it is more risky than say conduit fully inside or fully outside, both of which would achieve a similar end.

    That's before we get to the question of earthing and bonding the shared frame steels of units that have independent service heads.

    See what others say.

    Mike

  • 0
    Declan A said:
    If a tenant was to isolate their unit at the incomer, they would still have a live cable running through their unit

    Such things aren't unknown in a number of situations - e.g. multiple incomers, or local generation or UPSs. A few notices in suitable locations usually suffices though.

       - Andy.

  • 0 in reply to mapj1

    The cable is specified as a SWA, so I would agree it may not break regs but from a good practise perspective there is better ways to do it.


  • 0
    Declan A said:
    I am acting as the electrical engineer for a project
    Declan A said:
    The design currently proposes

    I think that you need to be very clear about your rôle: what are you responsible for please? Construction ± I&T, or the whole job including design?

    If you change the design, you probably become the designer.

  • 0 in reply to Chris Pearson

    Hi

    We have essentially just been employed to oversee the construction, we are taking no responsibility for the design

  • 0
    • Regulation 513.1 generally requires that all equipment, including connections, be installed in a way that allows for inspection, testing, and maintenance.
    • Regulation 526.3 mandates that every connection in a live conductor must be enclosed and accessible, except for specific scenarios:

    Examples of Inaccessible Areas: Connections hidden within a sealed wall, under a permanently fixed floor, or within a non-demountable structure are considered inaccessible

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