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Posted By Topic: Cladding penetration for cable

Sep 01 2019 18:09

Can anyone help with the requirements for weatherproofing a cable penetration through exterior cladding in particular for a new build and for exterior surface mounted lights. In the NZ Building Code Clause E2 - External Moisture page 101 clasue and page 102 figure 68 (I have included the web link) shows the requirements for sealing pipe and service penetrations. I have a number of surface mounted light fixtures to fix to fix to the exterior cladding of a new build, some above sliding doors onto the deck and some up/down feature lights. I would have thought you just need to silicon around the hole where the cable comes through the cladding and then seal around the light fitting itself where it fixes to the cladding, effectively the light fitting base is the 'flange plate' shown in figure 68...If anyone can shed some light if this method of install sounds correct or how best to install as per the building code NZS3604. I cant find anything in ASNZS3000 wiring rules explaining this.

Sep 01 2019 18:31

Builders and building inspect like too see flashing tape around the penetrations, whether it be a cable coming straight through the building paper or around a flexible conduit through the paper. A timber support usually helps, like a nog or dwang to keep it at the right height for the builders to bring it through the cladding, weatherboard or brick.


Sep 01 2019 19:52

try these, should be available from your electrical supplier

Sep 01 2019 22:10

Thanks yeah I have seen those trade seals, therma craft also have a range but both these trade seals are more suited to pipe or bigger cables, all I have is 1mm tps so will be a very small hole. I’m just wondering if we have to have a trade seal or will flashing tape suffice or silicon around cable or are we meant to put a piece of conduit through hole/penetration first and use trade seal and then run cable within the conduit...I would have thought there’d be some sort of requirement/guideline for this scenario as it must be pretty common. There must be plenty of fellow sparkies on here that have come across this and dealt with building inspector/council on what’s required...

Sep 02 2019 07:32

Yes for years now these seal have been what is required. You can get them small enough so they are tight on a 1 mm tw + e or if multiple cables put it in a flexible conduit.
The inspectors are also looking for them to be put in correctly which is diamond shaped with the point at the top not square so the water runs the correct way if it gets wet. Impossible to do later if the cladding is already installed. Some guys put them on the inside of the paper.

Sep 02 2019 08:11

Not that there's much if any differenc for this particular situation, but you appear to be referring to an older version of the compliance document Last amended December 2011; and now clearly labelled "archived".

Go to for the current edition.

You'll find nothing in wiring rules, because this isn't about the electrical aspects it's about the structure our cables are installed into.

So bookmark that URL, because there's a good chance of needing to look up this sort of stuff from time to time.


Sep 02 2019 08:45

Or these ones

Sep 02 2019 10:13

it is not possible to install the smaller of the last ones to MI's as there is no conduit available in new zealand

Sep 02 2019 18:08

it is intended that you use a piece of conduit and put your cables inside that, as per the diagram i put up.
Please don't use flexible conduit on anything you want to actually seal, always use conduit, you will achieve a much better seal, flexible conduit will most likely fail and leak, and i would suggest flexible would get bounced by the building inspector.