Proposal for 210.4(B)

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Dennis Alwon

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I want to make this exception proposal- please let me know what you think.

210.4(B) Disconnecting Means
(B) Disconnecting Means. Each multiwire branch circuit shall be provided with a means that will simultaneously disconnect all ungrounded conductors at the point where the branch circuit originates
Exception: Where a multiwire branch circuit with line to neutral loads must be used at a separate structure in order to comply with 225.30, and an alarm circuit is required for its safe operation is part of this multiwire branch circuit.


Substantiation

The definition of structure is that which is built or constructed. A post in the ground would meet this definition. Since a post is often used to install the alarm box for septic pumps and sewer lift pumps it is not possible to wire them without violating one of 2 codes. As the code is now we can either run 2 individual branch circuits and violate 225.30 or we use a multi-wire branch circuit and violate 210.4.(B) or 240.15(B)(1). The Dp breaker or handle ties on a muti-wire branch circuit would turn the alarm circuit off if there were a fault in the pump circuit. This would defeat the purpose of 2 circuits. This exception would alleviate that problem.
 
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infinity

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Your proposal makes perfect sense. IMO the real problem is with the NEC definition of a structure. A support system for the equipment that you've mentioned should be outside of the NEC definition of the word. Is this really a structure?

Two%20Rec%27s-One%20Structure.jpg
 

iwire

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IMO the real problem is with the NEC definition of a structure.

It mirrors the building codes definition of structure so I do not see that changing.




Is this really a structure?

Two%20Rec%27s-One%20Structure.jpg
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IMO without a doubt, but is it 'served' by either of those circuits?

There is no utilization equipment on it. This is a distinction Charlie E had pointed out to me.
 

infinity

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IMO without a doubt, but is it 'served' by either of those circuits?

There is no utilization equipment on it. This is a distinction Charlie E had pointed out to me.

Interesting. Do we now need an NEC definition of the word served. :grin:
 

Dennis Alwon

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Your proposal makes perfect sense. IMO the real problem is with the NEC definition of a structure.

I agree but as Bob said I don't think that will change. I started there but could not come up with a good definition so I take it as it is. A post in the grade is a structure, IMO.

I am also making a proposal to add another condition for art. 225.30(A) that will allow septic/ sewer systems have 2 circuits. A MWBC doesn't always work since some of these pumps are 240v with 120v alarms.
 

mtfallsmikey

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Musings from the house plumber...

Musings from the house plumber...

I agree but as Bob said I don't think that will change. I started there but could not come up with a good definition so I take it as it is. A post in the grade is a structure, IMO.

I am also making a proposal to add another condition for art. 225.30(A) that will allow septic/ sewer systems have 2 circuits. A MWBC doesn't always work since some of these pumps are 240v with 120v alarms.

I won't go near the definition of a structure, but Dennis' concept for 225.30 makes perfect sense.
 
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