25 foot tap rule

[ohmhead]

Has the rule changed as far as were it can be used is it still a industrial area ?

 

[Dennis Alwon]

The only change I see is this. The rest is the same-- this is the 2014 NEC - no changes in the 2017

(3) Industrial Installation Secondary Conductors Not
over 7.5 m (25 ft) Long. For the supply of switchgear or
switchboards in industrial installations only, where the
length of the secondary conductors does not exceed 7.5 m
(25 ft) and complies with all of the following:

 

[augie47]

IT's not a change, but you might want to check out 240.90 for "supervised industrial installations"

 

[ohmhead]

IT's not a change, but you might want to check out 240.90 for "supervised industrial installations"

So if it's not a industrial location you can not run a secondary from a transformer more than 25ft if not fused or protected at tap of supply ?

 

[Carultch]

So if it's not a industrial location you can not run a secondary from a transformer more than 25ft if not fused or protected at tap of supply ?

Also, is there an objective definition for an "industrial location"?

 

[iwire]

So if it's not a industrial location you can not run a secondary from a transformer more than 25ft if not fused or protected at tap of supply ?

For transformer secondaries look at 240.21(C)

 

[iwire]

Also, is there an objective definition for an "industrial location"?

In my opinion that is up to the AHJ.

 

[kwired]

So if it's not a industrial location you can not run a secondary from a transformer more than 25ft if not fused or protected at tap of supply ?

even if you run it 10 to 25 feet it must meet all the conditions mentioned in 240.21(C)(3) or (C)(6).

Only place that would allow more then 25 feet is (C)(4) for conductors outdoors.

 

[mayanees]

Also, is there an objective definition for an "industrial location"?

Yes, 240.2 Definitions - Supervised Industrial Installation

 

[iwire]

Yes, 240.2 Definitions - Supervised Industrial Installation

Yes there is a definition but item 1 is still subjective and IMPO up to the AHJ to determine not the installer or designer.

Supervised Industrial Installation. For the purposes of Part VIII, the industrial portions of a facility where all of the following conditions are met:

(1) Conditions of maintenance and engineering supervision ensure that only qualified persons monitor and service the system.

 

[mayanees]

Yes there is a definition but item 1 is still subjective and IMPO up to the AHJ to determine not the installer or designer.

IMPO and experience if conditions 2 and 3 are met, condition 1 is easy, if nothing else with lockable hasps on the ocpds.

 

[don_resqcapt19]

IMPO and experience if conditions 2 and 3 are met, condition 1 is easy, if nothing else with lockable hasps on the ocpds.

In some areas, condition one is read as requiring trained staff on site 24/7.

 

[iwire]

IMPO and experience if conditions 2 and 3 are met, condition 1 is easy, if nothing else with lockable hasps on the ocpds.

Here are the sections

Supervised Industrial Installation. For the purposes of
Part VIII, the industrial portions of a facility where all of
the following conditions are met:

(1) Conditions of maintenance and engineering supervision
ensure that only qualified persons monitor and service
the system.

(2) The premises wiring system has 2500 kVA or greater of
load used in industrial process(es), manufacturing activities,
or both, as calculated in accordance with Article
220.

(3) The premises has at least one service or feeder that is
more than 150 volts to ground and more than 300 volts
phase-to-phase.
This definition excludes installations in buildings used by
the industrial facility for offices, warehouses, garages, machine
shops, and recreational facilities that are not an integral
part of the industrial plant, substation, or control center.

I don't see anything about a lock, but I will not dispute your experiences. I will say it just goes to my point that item 1 is entirely subjective and up to the AHJ not the designer or installer.

 

[mayanees]

Here are the sections



I don't see anything about a lock, but I will not dispute your experiences. I will say it just goes to my point that item 1 is entirely subjective and up to the AHJ not the designer or installer.

Not to belabor the point, but for explanation purposes, if my client could prove objectively they had 2500kVA or more of manufacturing load, and met the service voltage requirement, then I would advise they document in their 70E-required Electrical Safety Program that there are preventive measures in place to prevent someone from adjusting the trip units on breakers (lockable hasps). I think the industrial exemptions are mostly directed at more lenient ampacity requirements in cable protection, like the summation of ocpds protecting a cable per 240.21C(3)(2).
My experience is from old-school industrials: Scott Paper, GF, P&G, DuPont, where Supervised Industrial Installations are a given, so my history is indeed biased.