M
Mega Greg
Just wondering about the potential heating problems of cables installed on or in the sunlit walls of sunlit conservatories and glass fronted rooms.
One air con company website refers to conservatories saying: "Perhaps the biggest problem is the very fact that they become far too hot in the summer (up to 50 C or 122 F)".
Clearly 20C above the ambient temperature mentioned in Appx 4 but we can also note the view that some surfaces in direct sunlight can get "hot enough to fry eggs".
I then image a situation in which householder A is working in the garden/garage/drive with noisy / dust making machinery which is fed from a sunlit wall while householder B keeps the conservatory doors and windows as closed as possible to keep the noise and dust out.
So far I've just got as far as to note that BS 7671 doesn't have a special location section for glass enclosed spaces in direct sunlight but that Appx 4 'Para' 2.1 admits - "...
The rating factors in Tables 4B1 and 4B2 do not take account of the increase, if any, due to solar or other infrared radiation" – (IR being one relevant form of electromagnetic radiation).
It then goes on to say:
"Where non-sheathed or sheathed cables are subject to such radiation, the current-carrying capacity may be derived by the methods specified in BS 7769 (BS IEC 60287)."
[I don't have a BS 7769. The big colour changing book was expensive enough].
The RCD protection of conservatory sockets would safeguard people from electric shock but I'm wondering about the effects on wiring in sunlight and the types that should be used.
One air con company website refers to conservatories saying: "Perhaps the biggest problem is the very fact that they become far too hot in the summer (up to 50 C or 122 F)".
Clearly 20C above the ambient temperature mentioned in Appx 4 but we can also note the view that some surfaces in direct sunlight can get "hot enough to fry eggs".
I then image a situation in which householder A is working in the garden/garage/drive with noisy / dust making machinery which is fed from a sunlit wall while householder B keeps the conservatory doors and windows as closed as possible to keep the noise and dust out.
So far I've just got as far as to note that BS 7671 doesn't have a special location section for glass enclosed spaces in direct sunlight but that Appx 4 'Para' 2.1 admits - "...
The rating factors in Tables 4B1 and 4B2 do not take account of the increase, if any, due to solar or other infrared radiation" – (IR being one relevant form of electromagnetic radiation).
It then goes on to say:
"Where non-sheathed or sheathed cables are subject to such radiation, the current-carrying capacity may be derived by the methods specified in BS 7769 (BS IEC 60287)."
[I don't have a BS 7769. The big colour changing book was expensive enough].
The RCD protection of conservatory sockets would safeguard people from electric shock but I'm wondering about the effects on wiring in sunlight and the types that should be used.