Running cables on outside wall.

[spynage]

I have a customer that wants a bathroom tv fitted next to the bath. No problem it's IP65 but the only suitable way to get power is by running the cables through the wall to the outside and down to a lean-to that has been equipped with a double rcd protected sockets. I was going to run the cables in metal earthed conduit. Ok? Just wondering about possible temperature problems inside. The cable is unlikely to overheat. Is there a high temp .75mm flex anyone can recommend?

Cheers.

 

[Guitarist]

Is the cable running down the wall going to be RCD protected itself, out of interest?

 

[Marvo]

Not sure why you think you may need a higher temp rated cable but you can go with an HO7 neoprene cabtyre cable (flex) if it's really necessary. I assume they make it as small as .75mm but the smallest I've ever used is 1mm.

 

[Guitarist]

I have to admit that I use H07 for all outside lighting etc., though I realise that I'm in the minority.

 

[Marvo]

Not sure about the prices in the UK but HO7 is a bit too expensive here to use as general installation cable. We often use other PVC hybrid alternatives depending on the application.

 

[Guitarist]

Not sure about the prices in the UK but HO7 is a bit too expensive here to use as general installation cable. We often use other PVC hybrid alternatives depending on the application.

Recently got a reel of 1mm for about 60p per metre. Considering I only use it where UV protection is needed, I think that's pretty good.

 

[Marvo]

We also pay about the same currency converting directly but a 100m coil of 1mm pvc is about ZAR200.00 (14p / meter) which is a big difference. Hybrid PVC such as 'mast-light' cable which is UV stable and 110 Celsius rated costs about 20p/meter. If you're only using short lengths it's not an issue but with long lengths paying 3 times the price could make a difference.

 

[spynage]

Thanks. I might go for some of that H07 CK cable rated to 90c. I thought thermoplastic wouldn't be suitable for sitting in metal conduit on a south facing wall.

cheers

 

[Engineer54]

Thanks. I might go for some of that H07 CK cable rated to 90c. I thought thermoplastic wouldn't be suitable for sitting in metal conduit on a south facing wall.

cheers

So when do you think the outside temperature is ever going rise a cables temperature to anywhere near 70 C let alone 90 C in the UK?? I'd be more worried about any UV degradation and freezing temperatures rather than high temperatures!! ...lol!!

 

[Guitarist]

H07 is ideal for most outside applications.

 

[Spoon]

My books are at work but doesn't the regs say that the minimum power cable size is 1.5mm?? (for lighting its smaller)

 

[Spoon]

As a follow up from my post above: check out Table 52.3. Page 130 BGB.

 

[Guitarist]

As a follow up from my post above: check out Table 52.3. Page 130 BGB.

I always find that table a bit ambiguous...
Non-flexible cables, 1mm for lighting, 1.5mm for "power". Ok, that's obvious.
Now, flexible cables can be basically anything a manufacturer decides, or 0.75 otherwise. Obviously this includes "fixed" flexible cables which are suitable for use, ie. heavy duty, or non-heavy duty with adequate mechanical protection.
So, if it's H07 (heavy duty), it can be 0.75mm with the correct OCPD, regardless of what it's for.

 

[Toby Kuhnert]

I have to admit that I use H07 for all outside lighting etc., though I realise that I'm in the minority.

I use H07 for lighting too.. love it!

 

[gazj82]

We usually use white FP200, not sure if this is the norm for anyone else? Or put the cable in a conduit. I always think conduit looks better than a clipped cable outside anyway.