ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Mini Split voltage
by Garemaret - 06/21/24 04:53 AM
Strobing LEDs
by Anovalight - 06/20/24 03:16 AM
Stuff that happens after we leave
by HotLine1 - 06/17/24 03:53 PM
photocell requirement for metal halide ballasts
by gfretwell - 06/17/24 01:44 PM
Commercial lift stations
by triple - 06/09/24 05:23 PM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
1 members (Scott35), 53 guests, and 9 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Joined: Jul 2002
Posts: 103
J
jes Offline OP
Member
250.4 clearly states that electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning...
It then goes on to talk about grounding and bonding of electrical equipment and other conductive materials that are "likely to become energized".
At what point are the grounding and bonding requirements required to deal with lightning protection and not just ground faults within the electrical system?? For example, would a metal chimney extending up above the highest point of the structure require bonding?? Why or why not?? If so, how do you determine the size of the bonding conductor? Let's say the metal fireplace has a fan. #14 AWG circuit with equipment ground. Is that sufficient to withstand a lightning strike?
Just curious how others view the wording of 250.

Stay up to Code with the Latest NEC:


>> 2023 NEC & Related Reference & Exam Prep
2023 NEC & Related Reference & Study Guides

Pass Your Exam the FIRST TIME with the Latest NEC & Exam Prep

>> 2020 NEC & Related Reference & Study Guides
 

Joined: Nov 2000
Posts: 2,148
R
Member
Lightning protection is covered by NFPA 780, the Lightning Protection Code. It is not really covered by the NEC.
Don


Don(resqcapt19)
Joined: Jul 2002
Posts: 103
J
jes Offline OP
Member
Don,
I am well aware of 780, nevertheless, those words ARE in the NEC, have been for YEARS. What do they really mean? Do they apply only to lightning voltages coming from the utility or source of supply?

Joined: Nov 2000
Posts: 2,148
R
Member
In my opinion, the NEC in 250.4(A)(1) is talking about limiting the voltages on the electrical system that result from outside influences such as lightning. Note that it does use the word system in this section. The other parts of this section use the word "equipment" and for the most part also uses the words "fault clearing path". I don't see anything that requires lightning protection of the electrical equipment or other conductive equipment in the NEC.
Don


Don(resqcapt19)

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5