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dancan

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Dear all, firstly, thanks for being there. I must make clear, I'm not a sparky, I'm a Fire Risk Assessor, but I've been asked some specific questions about external wiring and I don't know where to find the information. Any clues where to look please? The questions are about the standard/quality of cabling, the recommended types of fixings and the spacing/distancing of the fittings? I guess it might depend on what the installation is, but if anyone can point me in the right direction, I'd be grateful.
 
are you talking abour fire alarm cables or general electrical cables?
 
What questions have you been asked.
 
As other have said, very much depends on what you were asked.

Generic answer would be cables and fittings to be suitable for outside use (UV and water resistant, obviously) and supported in a way that will not create a hazard. With 18th edition regs some, if not all, cable support clips should be capable of avoiding cables dropping in a fire and impeding any exit route, etc.
 
Hello and thank you for being there. The original question is a bit vague (I'm awaiting clarification) but goes ' Dan can you send me the standards and guidance for fixing electrical cables to external walls. Types of fixtures, spacing etc. I just need to know where to look I suppose. BS 7671 ?
 
BS7671. reg 522.8. (that's from 17th ed, amd3). as a guide, i recollect eg. 2.5mm can
ble fixings spaced approx 200mm horizontal and 400 mm vertical. metal fixings should be used say, every 3rd one to prevent collapse in case of fire.
 
The IET guidance notes are more readable than the actual standard, and "Guidance Note 1 Selection & Erection" has a table with cable clip spacings, etc, in Appendix G.

Also cable fixing and circuit protection might depend on what your "outdoor" area is used for. The "Guidance Note 7 Special Locations" has summaries for various places that might be relevant (e.g. agriculture, etc)
 
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One of the more important regs from BS7671 is 521.10.202, but all of chapter 52 is relevant.
Appx D in the OSG is also useful but GN1 even more so.

Without more specific details it's piddling in the wind a bit. In what context has this info been asked of you ?
 
Dear all, I can't thank you enough for your kind and prompt assistance. The reason it's included in my Fire Risk Assessment is that cables are dropping across the final exits and could impede the escape route
 
Dear all, I can't thank you enough for your kind and prompt assistance. The reason it's included in my Fire Risk Assessment is that cables are dropping across the final exits and could impede the escape route

That is a serious issue and probably is covered by one or more HSE regulations even beyond the IET wiring standards.

Hopefully this gives you the ammunition you need to make sure the cables are properly fixed. Either with decent metal clips etc, or by fixing metal tray (or similar) horizontally for gravity support, or where stainless ties can be used for vertical support, to provide a heat resistant support that can easily take whatever combination of cable sizes and weights you need routed over such exits.
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It is a bit old (2015) but this advert-like article probably covers a lot of what you are facing:
 
I do many fire risk assessments and with these issues you need a modicum of knowledge as to the specific parts of the assessment. What is the question from the assessment format.
 
dear all,
May I thank you all for very kind and generous assistance, I genuinely, honestly appreciate it. At least I've got guidance about where to look and at least an answer to give back to my questioners. Thank you all so much. Keep safe, Dancan
 

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