I agree 100% with the premise.....I would prefer to see them as a 4 wire setup all the time.....IN fact MANY agree with that as well as their are simply too many " What If's " involved with 250.32(B)(2) but alas the NEC panel does not agree......so it will still be done and technically safe if done correctly.
I am confused however in your use of the term Switched or Fused Neutral in either setup. The neutral ( grounded ) conductor is solidly connected in either system setup…the only time we get into switching a neutral would be in a SDS setup…in which it defines THAT type of setup…so I am confused ( not argueing my friend…I think you know me now )…just trying to learn myself why you would consider it such.
Someone better explain your view to NFPA. They get it “wrong” (by your interpretation) in the handbook. Basically you are saying it is illegal to use a panelboard main breaker as the disconnect in a second building since that will not interrupt the neutral.
As greg stated…it is simply not a case where you want to even think about the “grounded” conductor being switched or fused…simply not the case when it comes to a detached building as in this question.
BTW if the hot rumor is true you will not get any help from 2008 code in Florida. There is a buzz that the 2008 will be skipped and they are going to stay with 2005 until the 11 code comes out. They plan to pick up anything they like with the “glitch” amendments to the FBC (as they did with the required bonding of steel framing)
Ahh…I see what you are saying…you are taking the term Disconnecting Means as literally the OCPD itself.
**Disconnecting Means. **A device, or group of devices, or
other means by which the conductors of a circuit can be
disconnected from their source of supply.
Ie: A location of the source of disconnection…not the actual OCPD located within…
**[FONT=Times-Bold][size=2]Circuit Breaker. **A device designed to open and close a
circuit by nonautomatic means and to open the circuit automatically
on a predetermined overcurrent without damage
to itself when properly applied within its rating.
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how exactly would this take place Jeff…none of the enclosures sold today for this purpose ( other than lets say a transfer switch for a SDS system ) would be designed to actually SWITCH the neutral ( grounded ) conductor in any way.
easy to read it literally…like in this statement as well…
**(5) Load-Side Grounding Connections.
**A grounding
connection shall not be made to any grounded circuit conductor
on the load side of the service disconnecting means
except as otherwise permitted in this article.
Basically they are refering to the Disconnection means as the enclosure as a whole…so basically in the 250.32(B)(2)…when they say disconnection means…they are refering to the whole enclosure itself that makes up the disconnection means for that setup…not JUST the OCPD itself.
Also this would limit that from happening as well…
**[FONT=Times-Bold][size=2]240.22 Grounded Conductor. **No overcurrent device shall
be connected in series with any conductor that is intentionally
grounded, unless one of the following two conditions is
met:
(1) The overcurrent device opens all conductors of the circuit,
including the grounded conductor, and is designed
so that no pole can operate independently.
(2) Where required by 430.36 or 430.37 for motor overload
protection.
so in allowance (1) above…don’t believe I have ever seen a 120/240 enclosure with a panelboard and OCPD that would do this…so it boils down to what is the term disconnection means in that statement…I believe it is the actual enclosure itself as a whole…does that clear it up any Jeff?
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lol…I would never think of it my friend…but in light of your thinking that the “grounded” conductor should be switched on a 3-wire setup…lol…I would suggest you continue to defer…:mrgreen: :mrgreen: :mrgreen: :mrgreen: …sorry I could not resist…:twisted:
Way back in the olden days (circa 1988 or so) a group of electrical professionals were hanging out on the Prodigy BBs. The homeowners accused us of being a “secret society” with an arcane dogma (the NEC). The name stuck and a number familiar names here got their “T” shirts with the Secret Society logo. A few of them were me (AKA DP), Joe Tedesco (AKA NecMeister) and our mutual friend Ryan Jackson (AKA Roper) who wrote the proposal that will kill 250.32(B)(2).
Some of the others are regular contributors on alt.electrical.engineering and the ECN groups but they try to stay a bit more anonymous.
Maybe this will help Jeff. Bonding the grounded conductor to the disconnect enclosure serves a very important function, as we all know. What function could a switched or fused neutral possibly serve in the case of a remote building on the same system?
Please don’t take this wrong, but many parts of the code are much easier to understand when a person has been in the trade for many years and understands electrical theory enough to understand the reasons behind a code requirement. Sadly there are still many “electricians” out there who do not understand basic theory.
I was not allowed to take my NEC classes until I had completed my theory classes. I was not happy with that, but now I see the reason for it. Of course I will be the first to admit that I don’t know it all. But one thing I do know, you are wrong in your interpertation of 250-32(B)(2) :mrgreen:
Don’t feel bad about it. The cryptic language of the NEC can get fistfights started in inspector meetings. 250 is always good for a fight and this is the new and improved, rewritten 250. In 99 they scrapped the whole article and started over.
If you really want to be confused look at 250.24 in the 96 code where this used to be covered. The intent never changed but the language is completely different.
Indeed, I did write and substantiate that proposal for Mike Holt, as I work for Mike on a part time consulting basis. I don’t where “Roper” came from though…
