Disconnection of grounded conductor

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ner

Member
Location
connecticut
I have been told that a two pole switch can serve as the disconnect for a MWBC to a shed. What about article 225.38 (C) 2005 NEC that says the neutral needs to be disconnected too. Do you install a terminal with pressure connectors in the box with the two pole switch or add another single pole switch or a three pole disconnect to satisfy this requirement? There is one 20 amp 120/208 volt MWBC in this situation.
 

acrwc10

Master Code Professional
Location
CA
Occupation
Building inspector
225.38 (exception)
If this is residential you can stop at the exception right after 225.38 and you dont need to have a disconnect on the neutral.
 
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acrwc10

Master Code Professional
Location
CA
Occupation
Building inspector
It is not residental.

I would use a small A/C disconnect, and add a neutral buss inside it, cheap and easy. That way you have your neutral point terminals.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I would use a small A/C disconnect, and add a neutral buss inside it, cheap and easy. That way you have your neutral point terminals.

Do they make neutral bars for those cheap disco's and are they service rated?
 

Dennis Alwon

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Location
Chapel Hill, NC
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Retired Electrical Contractor
I would use a small A/C disconnect, and add a neutral buss inside it, cheap and easy. That way you have your neutral point terminals.
And that would not be compliant unless that disco was suitable for service equipment. Most a/c disco are not.
 

acrwc10

Master Code Professional
Location
CA
Occupation
Building inspector
And that would not be compliant unless that disco was suitable for service equipment. Most a/c disco are not.

Good point, I don't think most are service rated but there are some cheap discos that are dervice rated. (Does it need to be service rated, since it is disconnecting a branch circuit?)
 

Dennis Alwon

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Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Good point, I don't think most are service rated but there are some cheap discos that are dervice rated. (Does it need to be service rated, since it is disconnecting a branch circuit?)
Yes. I think Raider wrote a proposal to get that changed.
 

Dexie123

Senior Member
Ok if I run a feed out to a subpanel into a garage i need to provide a disconnect for the two ungrounded conductors AND the neutral conductor? Would a 3 phase service rated disco suffice?
 

acrwc10

Master Code Professional
Location
CA
Occupation
Building inspector
Ok if I run a feed out to a subpanel into a garage i need to provide a disconnect for the two ungrounded conductors AND the neutral conductor? Would a 3 phase service rated disco suffice?

Look at 225.38(C) ......"a terminal or bus to which all grounded conductors can be attached"........
a Neutral bus, just like any other panel, with lugs/terminals are fine. You really don't want a switch on the neutral if you can avoid it.
 
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