Power to Systems Furniture

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Dom Pastore

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Article 605.7 would seem to require that multiple 120 volt circuits feeding systems furniture would require a multiple-pole breaker controlling these circuits. Is this correct? Are these 120 volt circuits considered a "multiwire branch circuit" would would require simultaneous tripping?
 
Article 605.7 would seem to require that multiple 120 volt circuits feeding systems furniture would require a multiple-pole breaker controlling these circuits. Is this correct?
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Only if the multiple circuits are a multiwire branch circuit. Take a look at the definition of a multiwire branch circuit in Article 100

Also this section doesn't require a common trip breaker, just a common handle tie to disconnect the branch circuits simultaneously.

Chris
 
All the ones I've wired were wired for a multi-wired type connection. Has anyone seen a system using individual neutral connections?
 
The ones I've messed with have a 3-hot-plus-neutral MW circuit with an oversized neutral, and a separate single hot-and-neutral circuit, all of which share a single EGC.
 
LarryFine said:
The ones I've messed with have a 3-hot-plus-neutral MW circuit with an oversized neutral, and a separate single hot-and-neutral circuit, all of which share a single EGC.
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Yes, supply a oversized neutral here.
 
JohnJ0906 said:
The ones I have done spec an oversized neutral. Isn't the reason for this is that it supposedly reduces harmonic currents?
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The over sized neutral can not reduce harmonic currents.

The over sized neutral is supposedly there to compensate for the added current that the non-linear loads generate.

If its in the spec go ahead and install it.

My point here is that most of the info out there that says we need a 'super neutral' is generated from companies that make money from fixing a problem that no one seems to see happening in real life.

Many furniture feed whips come with an over sized neutral....but that stops where it connects to the furniture, the neutral in the internal furniture harness is no bigger than the phase conductors.
 
JohnJ0906 said:
The ones I have done spec an oversized neutral. Isn't the reason for this is that it supposedly reduces harmonic currents?
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I believe it is that if you have harmonics the neutral carrys additional current that requires a larger neutral. The harmonics will not be reduced by using a larger neutral, just the neutral wire will not be overloaded.
 
"All the ones I've wired were wired for a multi-wired type connection. Has anyone seen a system using individual neutral connections?"

To answer this question there is a system furniture that uses individual neutrals the system is known as 3,3,2 for an 8 wire system and 4,4,2 for a ten wire system.
 
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