# 4 circuit Furniture Feed breaker tie



## user4818 (Jan 15, 2009)

Only the MWBC's of a furniture feed are required to be handle tied. There is no such thing as a 4-wire MWBC. I'm assuming you have a 3-wire MWBC and one "clean power" circuit with an IG. There is no requirement for all of the to disconnect simultaneously - only the 3-wire MWBC must be disconnected simultaneously.


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## william1978 (Sep 21, 2008)

Peter D said:


> There is no such thing as a 4-wire MWBC.


 Black,red,blue,white.


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## william1978 (Sep 21, 2008)

Use a 3-pole and a single pole breaker.


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## user4818 (Jan 15, 2009)

william1978 said:


> Black,red,blue,white.


No kidding.  I'm talking about the number of ungrounded conductors. There's no such thing as a MWBC with four ungrounded conductors.


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## user4818 (Jan 15, 2009)

william1978 said:


> Use a 3-pole and a single pole breaker.


You're missing the point. _It's not required at all to handle tie all for circuits together._ Only the MWBC portion of the furniture feed needs to be simultaneously disconnected. The additional 2-wire circuit, which may originate from an isolated ground panelboard, does not require simultaneous disconnection with the MWBC.


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## circuit480 (Oct 20, 2009)

*furn feed specs*

For clarification the furniture system in question requires the following:
Four phase conductors, two neutral conductors and two ground conductors...


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## user4818 (Jan 15, 2009)

circuit480 said:


> For clarification the furniture system in question requires the following:
> Four phase conductors, two neutral conductors and two ground conductors...



That still allows the possibility of one three-wire MWBC and one two-wire IG circuit since you mentioned "two ground conductors." 


Or, two two-wire MWBC's. In that case, once again, only the individual MWBC portions of the furniture feed need to be simultaneously disconnected. Both MWBC's are not required to be, and in fact, _cannot be_ if one circuit originates from an IG panelboard.


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## MDShunk (Jan 7, 2007)

circuit480 said:


> For clarification the furniture system in question requires the following:
> Four phase conductors, two neutral conductors and two ground conductors...


Right. You're going to have a 3-pole MWBC and a single pole circuit. Use a 3-pole breaker and a single pole breaker. You don't need to handle tie those together.


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## user4818 (Jan 15, 2009)

MDShunk said:


> Right. You're going to have a 3-pole MWBC and a single pole circuit. Use a 3-pole breaker and a single pole breaker. You don't need to handle tie those together.


Isn't that what I've been saying all along? 

I'm still not convinced that these originate from the same panelboard based on the "two ground wires" comment.


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## Bob Badger (Apr 19, 2009)

Déjà vu! this question seems so familiar. 



mdshunk said:


> Right. You're going to have a 3-pole MWBC and a single pole circuit. Use a 3-pole breaker and a single pole breaker. You don't need to handle tie those together.


Exactly what I said somewhere else




Peter D said:


> I'm still not convinced that these originate from the same panelboard based on the "two ground wires" comment.


Think green and green with yellow tracer.

It could come from one or two panels depending on the engineers preferences.

BTW Iz hatz speelen coppers.


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## william1978 (Sep 21, 2008)

Peter D said:


> Isn't that what I've been saying all along?
> 
> I'm still not convinced that these originate from the same panelboard based on the "two ground wires" comment.


 Why wouldn't they come from the same panelboard?


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## william1978 (Sep 21, 2008)

Peter D said:


> You're missing the point. _It's not required at all to handle tie all for circuits together._ Only the MWBC portion of the furniture feed needs to be simultaneously disconnected. The additional 2-wire circuit, which may originate from an isolated ground panelboard, does not require simultaneous disconnection with the MWBC.


 I never said tie all four cir's together. So how am I missing the point?


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## user4818 (Jan 15, 2009)

william1978 said:


> Why wouldn't they come from the same panelboard?


Isolated ground circuits aka "clean power" often originate from a separate panelboard.

THINK, BILLY, THINK!!!!!


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## user4818 (Jan 15, 2009)

william1978 said:


> i never said tie all four cir's together.



Right.


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## william1978 (Sep 21, 2008)

Peter D said:


> Isolated ground circuits aka "clean power" often originate from a separate panelboard.
> 
> THINK, BILLY, THINK!!!!!


 Just because it has a isolated ground doesn't make it clean power. I have yet to see furniture feed from a ups.


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## user4818 (Jan 15, 2009)

william1978 said:


> Just because it has a isolated ground doesn't make it clean power. I have yet to see furniture feed from a ups.


It could or it couldn't. We don't have that information. I'm just leaving the door open to that possibility.


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## william1978 (Sep 21, 2008)

:thumbsup:


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## user5941 (Mar 16, 2009)

Peter D said:


> Isolated ground circuits aka "clean power" often originate from a separate panelboard.
> 
> THINK, BILLY, THINK!!!!!


 Often? Idon't think so. I think you are confusing an IG circuit with an 
emergency circuit






















/


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## user4818 (Jan 15, 2009)

rewire said:


> Often? Idon't think so. I think you are confusing an IG circuit with an
> emergency circuit


I'm not confusing anything. It's not far off the mark to assume that an office environment with dozens of IG circuits could originate from separate panelboard fed with a K-rated transformer. Or not. We simply don't know in this case.


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## william1978 (Sep 21, 2008)

Sounds like we need the OP to give us a little more info.


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## leland (Dec 28, 2007)

MDShunk said:


> Right. You're going to have a 3-pole MWBC and a single pole circuit. Use a 3-pole breaker and a single pole breaker. You don't need to handle tie those together.



They only have to disconnect together, not trip together.
4 SP. tie 3 together.


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## Bob Badger (Apr 19, 2009)

william1978 said:


> Just because it has a isolated ground doesn't make it clean power. I have yet to see furniture feed from a ups.





rewire said:


> Often? I don't think so. I think you are confusing an IG circuit with an emergency circuit
> /



You guys need to get around more, I have done plenty of office cubes where the forth circuit comes from a separate panel supplied by a separate transformer, sometimes it will have a UPS sometimes not.

In this case I do think we are talking about 1 panel.


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## user5941 (Mar 16, 2009)

Bob Badger said:


> You guys need to get around more, I have done plenty of office cubes where the forth circuit comes from a separate panel supplied by a separate transformer, sometimes it will have a UPS sometimes not.
> 
> In this case I do think we are talking about 1 panel.


Why would I want to go to MA just a bunch of flamin liberals, but it is not common in the rest of the world maybe its just your local thing. I have run the IT room on a seperate panel and through an isolating transformer .Most of our EE are smart enough to know that you don't need to add a panel just for an IG but how smart do you have to be to live in MA..


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## william1978 (Sep 21, 2008)

Bob Badger said:


> You guys need to get around more, I have done plenty of office cubes where the forth circuit comes from a separate panel supplied by a separate transformer, sometimes it will have a UPS sometimes not.
> 
> In this case I do think we are talking about 1 panel.


This is not very common around here, and I'm not coming up there for sure. It is common around here in sever rooms but not in the furniture.


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## Bob Badger (Apr 19, 2009)

rewire said:


> Why would I want to go to MA just a bunch of flamin liberals,


Well I assumed you and your boyfriend would be coming up to get married .




> Most of our EE are smart enough to know that you don't need to add a panel just for an IG but how smart do you have to be to live in MA..


It's lucky you have them smart EEs as you apparently have no clue.

Often it has more to do with the power for the PCs in the cubes coming from a panel dedicated for electronics, sometimes backed with a UPS.

As far as the IGs they are a total waste of time in office cubes.


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## captkirk (Nov 21, 2007)

(Sigh) why cant we all just get along. ....?


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## william1978 (Sep 21, 2008)

Bob Badger said:


> Well I assumed you and your boyfriend would be coming up to get married


 Ouch.:laughing:


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## william1978 (Sep 21, 2008)

captkirk said:


> (Sigh) why cant we all just get along. ....?


 Is it time for a group hug? :no:


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