Article 110-24 Available fault current

Status
Not open for further replies.
B

Bill Wells

Member
Location
Gainesville, FL, USA
I recently built a service with a two-circuit panel for a sign at a church. The sign requires a 120-volt circuit and draws six amps. I used a 10k rated breaker for the project. The available fault current at the service is 7700 amps. The inspector turned the job down because I did not put an available fault current label on the panel. I realize the NEC states this is necessary. I have spoken to several engineers in the past about fault current rating and most have said that this calculation is not really necessary until you get into larger services starting at 200 amps and above. I am looking for feedback on this situation.
 
electrofelon

electrofelon

Senior Member
Location
Cherry Valley NY, Seattle, WA
Bill Wells said:
I recently built a service with a two-circuit panel for a sign at a church. The sign requires a 120-volt circuit and draws six amps. I used a 10k rated breaker for the project. The available fault current at the service is 7700 amps. The inspector turned the job down because I did not put an available fault current label on the panel. I realize the NEC states this is necessary. I have spoken to several engineers in the past about fault current rating and most have said that this calculation is not really necessary until you get into larger services starting at 200 amps and above. I am looking for feedback on this situation.
Click to expand...
Like it or not, the code says what it says. I recently got called on the same thing for not putting the label on a 100A temp service for a commercial site. I was aware of the requirement but it just never even crossed my mind to put it on there for such a small temporary service.
 
petersonra

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Bill Wells said:
I recently built a service with a two-circuit panel for a sign at a church. The sign requires a 120-volt circuit and draws six amps. I used a 10k rated breaker for the project. The available fault current at the service is 7700 amps. The inspector turned the job down because I did not put an available fault current label on the panel. I realize the NEC states this is necessary. I have spoken to several engineers in the past about fault current rating and most have said that this calculation is not really necessary until you get into larger services starting at 200 amps and above. I am looking for feedback on this situation.
Click to expand...
How hard is it to take a sharpie and and mark the available short-circuit current on the panel?
 
N

NTesla76

Senior Member
Location
IA
Occupation
Electrics
electrofelon said:
Like it or not, the code says what it says. I recently got called on the same thing for not putting the label on a 100A temp service for a commercial site. I was aware of the requirement but it just never even crossed my mind to put it on there for such a small temporary service.
Click to expand...
As an inspector, I would never have given it a second thought to require a label on a 100 amp temp service. I guess it is a requirement though.
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
electrofelon said:
110.16 would not apply to the equipment in the OP.

What I was getting at is, by my reading of the code, the 110.24 marking is not subject to the "cant be handwritten" requirements in 110.21(B)
Click to expand...
Yes, I realized 110.16 did not apply after I posted.
That would make the question whether the marking required by 110.24 is a "hazard marking". I can see that it could be considered such a marking. However, others may not see it as such a marking.
 
Status
Not open for further replies.
Top