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Formula for values in Table 52.2 - cables passing through thermal insulation?

Ben Gregory over 3 years ago

Does anyone know the formula used to get the values given in table 52.2 BS7671, (now moved to Appendix 4 item 2.6) please?

Not how to apply the values, this is obvious.

Many thanks

Ben

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0 Roger B over 3 years ago

As Geoff says this was done by experiment. I carried out some early work at Pirelli in the late 70s. This was prompted by my father who was on the wiring regulation committee. The first trials were with a model plasterboard and joist ceiling and a selection of different insulating materials. A number of different cross sections of T&E were used.

These trials showed that there was a possible problem and the work was passed on for more precise measurements to be made. I think I still have a copy of my original report.
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0 Roger B over 3 years ago

As Geoff says this was done by experiment. I carried out some early work at Pirelli in the late 70s. This was prompted by my father who was on the wiring regulation committee. The first trials were with a model plasterboard and joist ceiling and a selection of different insulating materials. A number of different cross sections of T&E were used.

These trials showed that there was a possible problem and the work was passed on for more precise measurements to be made. I think I still have a copy of my original report.
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0 Ben Gregory over 3 years ago in reply to Roger B

Hi Roger,

Many thanks for the response. Amazing that you might even have a copy of the old report!

Cheers

Ben
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