Disconnect and HVAC labeling sanity check

[Dell3c]

Infinity.. For it's worth, checked 2020 Analysis of Change, NFPA 70/ International Association Electrical Inspectors (I.A.E.I).. And your absolutely correct in explanation, in their version of printed text.

 

[infinity]

Since there is more than one way to read it, the above suggests you've chosen the wrong one. : - )

Cheers, Wayne

We can agree to disagree.
I'm not sure how you can say it must be marked unless the purpose is evident and then say it must be marked.

 

[wwhitney]

I'm not sure how you can say it must be marked unless the purpose is evident and then say it must be marked.

But it doesn't say "marked unless the purpose is evident".

The first sentence can be read like this:

(Each disconnecting means shall be legibly marked) (to indicate its purpose unless located and arranged so the purpose is evident).

So the "unless" phrase only applies to the part about "indicate its purpose". Which is only logical.

Cheers, Wayne

 

[jim dungar]

I agree it is poorly worded and probably not written correctly. Mike Holt in his 2020 code changes book disagrees with me however is says what it says. If no label is required for switches where there purpose is evident (like a disconnect feeding an AC right next to it) then how can you require certain information on the label that isn't required in the first place?

Each disconnecting means shall be legibly marked to indicate its purpose unless located and arranged so the purpose is evident.

The sentence you quote deals specifically with providing information about the purpose of the disconnecting means.
The next requirement deals with providing information about the source of the feed to the disconnect.

I see the purpose portion as being 'optional' but the source portion, and therefore a label, as being required.

 

[infinity]

But it doesn't say "marked unless the purpose is evident".

The first sentence can be read like this:

(Each disconnecting means shall be legibly marked) (to indicate its purpose unless located and arranged so the purpose is evident).

So the "unless" phrase only applies to the part about "indicate its purpose". Which is only logical.

Cheers, Wayne

Every word after the word evident refers to how it must be marked. If it's not required to be marked (because it's located and arranged so the purpose is evident) then those words are not relevant.

 

[wwhitney]

Again, given the subsequent sentences, the scope of the phrase "unless . . . evident" is obviously just "to indicate its purpose" and does not extend to the part about "shall be legibly marked."

It does not say "marked unless the purpose is evident."

Cheers, Wayne

 

[jimport]

Depends on how that sentence is parsed. A comma would have made it more clear.

 

[Dell3c]

Infinity.. For it's worth, checked 2020 Analysis of Change, NFPA 70/ International Association Electrical Inspectors (I.A.E.I).. And your absolutely correct in explanation, in their version of printed text.

Ok.. Appears, I was little "hasty" in my posting, just reading the "Code Language" in 2020 Analysis, (page 45) but not fully reading the entire "Revision" type change in this text. (also on page 44). So for me personally, this does clean the interpretation up in wording.

Change @ a Glance: Disconnects are now required to identify of the source of the branch circuit or feeder for the disconnect at the disconnecting means enclosure (other than one-or two-family dwellings).

2017 Requirements: A disconnecting means was required to be legibly marked with a sufficiently durable label to indicate its purpose unless the purpose was evident. There was no requirement for making the source of supply for the disconnect.

2020 Requirement: In addition to being marked with the purpose of the disconnect, requirements were added to demand the identification of the circuit source that supplies the disconnecting means (other than one-two family dwellings).

Then Article next quotes Code Language as found in NFPA 70.

Analysis of Changes: A disconnecting means is required to be marked with a label to identify exactly what the disconnect is for. If the disconnect is installed right next to something like a motor and the wiring method goes right to the motor, no label is required as it is evident as to the purpose of the disconnect. This label or marking is required to suitable of whatever environment where the disconnect is installed such as outdoors.

For the 2020 NEC this label or marking is also required to provide identification of the source that supplies the disconnecting means. This identification of circuit source does not apply to a disconnect installed at one-or two- family dwellings units.

By identifying the source of the circuit (branch circuit or feeder) at the disconnecting means enclosure, this will bring this requirement in line with 408.4(B) for the same identification requirements for switchboards, switchgear, and panelboards. During the 2011 NEC development process, this provision was added at 408.4(B) for indication of "Source of Supply" for all non-dwelling unit switchboards and panelboards supplied by a feeder to be marked as to the specific device or equipment where the power supply originates. Switchgear was added to this requirement in the 2014 NEC.

Many times, in industrial, commercial, and multifamily occupancies with multiple disconnects located throughout the buildings, and or around premises, it can be difficult to locate the source of supply for an individual disconnect. The time-consuming task in locating the power supply source can be critical in a emergency situation and exasperating during normal maintenance operations. The added wording of " shall include the identification of circuit source" requires requires the identification or marking to show a specific device and location. A general reference to a location such as "Electrical Room 2" will not be sufficient for this requirement. The final marking should require notation of specific devices. This power supply identification practice will enhance the safety for the electrical personnel who service these disconnects.

Now.. I dislike typing "long-winded explanations", but felt the need in redeeming my above posting in error. Have a safe evening, Dell is retiring for the evening.