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CMS
Former Community Member
Hi everyone, this is my first post , after spending 8 hours on line and no success ,being an M&E Manager electrically biased, I check for conformity on twelve domestic construction sites, one in particular has a design and build electrical contractor, my issue is in the electrical intake room in the basement of a new build 5 storey apartments, the tray and trunking is installed to a good standard however all the conduit from a stop end box on the trunking is in white plastic, at least 60 lengths serving both high level lights, sockets and life safety systems, can someone please tell me is their is a BS or regulation which opposes this install, also where do the fire regulations sit with this.
Welcome to the forum - we probably need a bit more info about your concern.
however some general points for starters.
If the question was is it OK to go from cable tray to plastic conduit?, then yes, generally it is. (or from metal to plastic enclosures and back in any sequence really.)
If however if the question is more are there regs to keep in mind for plastic conduits?, Oh yes.
For example, in a fire cable supports must not fail in a way that could entrap someone escaping - so there should be some if not all metal clips/straps or similar if this could happen. Clearly a cable sagging down a wall beside a corridor is ugly but not an immediate safety issue, but a similar level of drooping over a doorway or stairwell might be very serious. Detailed info about the situations is needed to judge (or just specify metal clips anywhere there is a long unsupported span seems to be some folks preferred approach.)
There should be questions about fire zones, and how these conduits (and cables more generally) get from one zone to the next - intumescent seals that rise like bread when heated and then block off flames and smoke while folk escape need to be fitted in the right places - what the right places are we do not know of course, but any hole in a wall you can feel a draught through is bad, and missing bricks etc. should raise a query.
There may be more, and I may not have fully understood what you were asking, looking forward your reply.
What sort of 'life safety systems' do yo have in mind - alarms have their own rules and may require different cable types.
Welcome to the forum - we probably need a bit more info about your concern.
however some general points for starters.
If the question was is it OK to go from cable tray to plastic conduit?, then yes, generally it is. (or from metal to plastic enclosures and back in any sequence really.)
If however if the question is more are there regs to keep in mind for plastic conduits?, Oh yes.
For example, in a fire cable supports must not fail in a way that could entrap someone escaping - so there should be some if not all metal clips/straps or similar if this could happen. Clearly a cable sagging down a wall beside a corridor is ugly but not an immediate safety issue, but a similar level of drooping over a doorway or stairwell might be very serious. Detailed info about the situations is needed to judge (or just specify metal clips anywhere there is a long unsupported span seems to be some folks preferred approach.)
There should be questions about fire zones, and how these conduits (and cables more generally) get from one zone to the next - intumescent seals that rise like bread when heated and then block off flames and smoke while folk escape need to be fitted in the right places - what the right places are we do not know of course, but any hole in a wall you can feel a draught through is bad, and missing bricks etc. should raise a query.
There may be more, and I may not have fully understood what you were asking, looking forward your reply.
What sort of 'life safety systems' do yo have in mind - alarms have their own rules and may require different cable types.
