T&E outdoors?

[bonesetter]

Hi all,

First post in this section of forum.

I'm installing a Vaillant outside temperature sensor which will be wired back to the boiler in the loft and would like advice on cable type/installation.

The cable run will be about 2metres vertically to the eaves from the bottom entry sensor which will be mounted on a NW facing wall, which is 8ft from adjacent property wall. No direct sunlight.

Is white PVC T&E suitable for this application considering long term UV degradation of sheath and clips?

The top half of my house is rendered and painted magnolia so don't really want to have a black cable although the black sheath would be more resistant to UV effects.

Black cable possibilities appear to be:
1. Tough Rubber Sheath Flex
2. Hi Tuf PVC/PVC

Can these be painted (exterior emulsion) without ill effects to sheath?

 

[Taylortwocities]

Duplicate post. See //www.diynot.com/forums/electrics/te-outdoors.316425/

 

[Space cat]

I always put outside cables in heavy duty PVC conduit, which you can get in white:

http://www.screwfix.com/c/electrical-lighting/trunking-conduit/cat830492

If the sensor has an entry point designed to take conduit you can use it; otherwise put a gland at the bottom. The top can go up through the soffit board.

 

[ericmark]

The oval shape of T&E is not easy to seal with a standard stuffing gland and so I would avoid using outside. I would select a round cable.

Clearly you realise black is the better colour for UV light but I would think the sensor will be extra low voltage and even if the cable did degrade over time it is unlikely to cause a danger.

Once you paint the cable clearly it will no longer have a UV light problem but the leaching of oils etc from the cable has caused problems with polystyrene being refereed to many times as causing problems.

But this will take quite some time and I think if you do a quick risk assessment you will see that the time scale for cable replacement is that long it's just not worth worrying about with extra low voltage so I would just use flex what every colour pleases you and maybe inspect every 10 years with rest of system to see if it's degraded enough to need replacement.

 

[bonesetter]

Well I think this will be ok http://www.batt.co.uk/products/view/547/318TRS-Rubber-Cable-300/500V-to-BS6500-H05RR-F and it's 7.1mm O/D.

Had a look at the HiTuf too but O/D is 11.5mm so too big for the gland and don't want to gland on inner sheath.

I'll paint it to match house.

 

[TicklyT]

IF the cable is just carrying ELV at signal levels, and no mains voltages, an alarm / structured wiring / telecomms cable may be adequate.

 

[MJN]

Is white PVC T&E suitable for this application considering long term UV degradation of sheath and clips?

The top half of my house is rendered and painted magnolia so don't really want to have a black cable although the black sheath would be more resistant to UV effects.

You could paint the cable and clips (magnolia) to not only blend in with the render but also provide the necessary UV protection.

Alternatively, how about positioning the sensor under the eaves? For the purposes of what the sensor is required to do (measure ambient outdoor temperature) I would not expect there to be any difference in measurement from there to 2 metres below.

Mathew