Rules and Guidelines

Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

State Helpful Answer
Locked Locked
Replies 4 replies
Subscribers 35 subscribers
Views 1410 views
Users 0 members are here

Options

You may also be interested in

This discussion is locked.

You cannot post a reply to this discussion. If you have a question start a new discussion

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

+1 GeoffBlackwell over 3 years ago

This was dealt with by an IEE Wiring Regulations committee called WR2. I was on WR2 as the NICEIC representative in the early 1990's.

This table was reviewed by WR2 but , as I recall, the data came to WR2 via ERA Technology Ltd. I pretty sure the data was mainly produced from experiments and I don't recall any formulas.

Regards

Geoff Blackwell
Cancel
Vote Up +1 Vote Down

Cancel
0 Ben Gregory over 3 years ago in reply to GeoffBlackwell

Many thanks Geoff, great to have access to first hand information from yourself.

Cheers

Ben
Cancel
Vote Up 0 Vote Down

Cancel
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.
Cancel
Vote Up 0 Vote Down

Cancel
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
Cancel
Vote Up 0 Vote Down

Cancel

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.