sharan123
Member
- Location
- Naperville, IL
- Occupation
- Electrical Engineer
Can building steel be used as a down conductor? Or you need to have a separate down conductor? This is for Data center buildings.
Lightning protection systems are always an engineered and or listed item. So the answer is either the PE puts his seal on such a thing and that makes it ok, or UL says it is ok and that makes it ok. Otherwise, it is not ok.Can building steel be used as a down conductor? Or you need to have a separate down conductor? This is for Data center buildings.
Really the guy you should be asking is the PE that sealed the lightning protection system drawings, or the UL listed lightning protection system contractor that will be designing your system.Dedicated wire down conductors or building steel, or both, must be installed in accordance with NFPA 780 (see section 4.9.9). This seems to be a grey area. Are both accepted?
A forth reference I forgot to add:Several references I found in web searches indicate that steel framing members can be used as down conductors if verified to be electrically continuous from the roof to the ground. However, as mentioned previously, it will be a function of the certifying designer to whether they utilize steel framing members as down conductors in their design.
References:
1) NECA 781
2) An Introduction to Static Electricity and Lightning Protection Systems, Course E02-018, J. Paul Guyer
3) NWS Manual 30-4106, NOAA Lightning, Grounding, Bonding, Shielding, and Surge Protection Requirements
ThanksLPI-175-2017 Std of Practice for the Design, Installation, Inspection of LPS's