# fault current markings



## D-Bo (Apr 15, 2012)

where do you typically place labels indicating available fault current and protection provided by gear? i guess my question is would you provide this information at the switchgear _and_ all subs or just at the primary switch


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## HARRY304E (Sep 15, 2010)

D-Bo said:


> where do you typically place labels indicating available fault current and protection provided by gear? i guess my question is would you provide this information at the switchgear _and_ all subs or just at the primary switch


This is from the 2011 NEC.


"110.24 Available Fault Current.
(A) Field Marking. Service equipment in other than
dwelling units shall be legibly marked in the field with the
maximum available fault current. The field marking(s) shall
include the date the fault current calculation was performed
and be of sufficient durability to withstand the environment
involved.
(B) Modifications. When modifications to the electrical
installation occur that affect the maximum available fault
current at the service, the maximum available fault current
shall be verified or recalculated as necessary to ensure the
service equipment ratings are sufficient for the maximum
available fault current at the line terminals of the equipment.
The required field marking(s) in 110.24(A) shall be
adjusted to reflect the new level of maximum available
fault current.
Exception: The field marking requirements in 110.24(A)
and 110.24(B) shall not be required in industrial installations
where conditions of maintenance and supervision ensure
that only qualified persons service the equipment."


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## D-Bo (Apr 15, 2012)

thanks, saved me a trip of looking it up myself:thumbsup:. i guess im still a little unclear on what's required. i have a 3000a 277/480v service with a 3000a main switch. i will get the available fault current from the poco tomorrow and slap it on the service with the date and be good? i don't see why i would need anything else considering the rating for the gear is printed right on the thing


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## don_resqcapt19 (Jul 18, 2010)

D-Bo said:


> thanks, saved me a trip of looking it up myself:thumbsup:. i guess im still a little unclear on what's required. i have a 3000a 277/480v service with a 3000a main switch. i will get the available fault current from the poco tomorrow and slap it on the service with the date and be good? i don't see why i would need anything else considering the rating for the gear is printed right on the thing


That is all that is needed to comply with the rule in the NEC. A lot more is required to comply with NFPA 70E.


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## HARRY304E (Sep 15, 2010)

D-Bo said:


> thanks, saved me a trip of looking it up myself:thumbsup:. i guess im still a little unclear on what's required. i have a 3000a 277/480v service with a 3000a main switch. i will get the available fault current from the poco tomorrow and slap it on the service with the date and be good? i don't see why i would need anything else considering the rating for the gear is printed right on the thing


Cool.........:thumbsup:


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