Running cables from CU into trunking

[Tricky Dicky]

I am running 50mm X 50mm plastic trunking round the perimeter of garage at ceiling level and planning to drop conduit down to switches and sockets. How do I feed cables from the CU into the trunking and retain the fireproof integrity of the CU? Do I need to use glands or are there alternatives. I was thinking of using galvanised couplers and brass male bushes to attach to the CU and trunking and then filling the space with intumescent sealer once the cables are in situ. I will be using anti droop clips in the trunking.

How far apart do they need to be and do I only need to use them just above doorways or the full extent of the trunking?

Richard

[ARW]

Nothing wrong with intumescent sealant where the cables enter the CU (about £3.50 for a tube of Fire Mate at Toolstation.

As for the spacings of the clips. That's easy. Imaging the trunking just instantly disappears and then just fit the clips where you need them to keep all the cables roughly held up to the ceiling.

[Tricky Dicky]

Just to clarify Adam, the last time I did something similar was a long time ago. Then I simply made holes in the side of the trunking matching the CU knockouts. Can I do the same but use intumescent sealant once the cables are passed through?

[ARW]

I think I might have slightly misread your question. I assumed (without thinking) that you were running the trunking up from the CU to the ceiling perimeter trunking and just using conduit on the drops to the sockets etc. If that was the case I would [1] use the largest bush and lock ring possible to fit inside the trunking as an entry point into the CU (and then fill the gaps with Fire Mate).

Your way is absolutely fine but harder work if you have several drops of conduit to the CU.

And yes you just fill the gaps either way when you are done.

[1] Another option with the trunking method is to jigsaw a square out of the top of the CU and use grommet strip that fits neatly inside the trunking.

[Tricky Dicky]

Thanks for the advice Adam, I hope to make a start soon as get my other problem sorted - see Wanker Roofers.

Richard

[Roger Hayter]

Sorry for the OT, but where do you get grommet strip? Sounds great, I always used cut grommets, but they are clearly not ideal.

[ARW]

Electrical wholesalers.

It seems that Screwfix and Toolstation do not sell it.

[Roger Hayter]

TLC do one, just a matter of knowing what it is called. Thanks. Does anyone do rubber ones, or aren't they flexible enough for corners?

[ARW]

The one's I have used are pretty much the same. And you nearly always have to superglue it on.