AFCI BREAKER PROBLEM - NEED CONFIRMATION.

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kwired said:
As I said once the complex reaches certain size (or other conditions) three phase sort of becomes a necessity.

Not so large and all on one level - single phase might be the prime choice there.
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Generally, apartment complexes here top out at 3 floors, and are anywhere from 100-800 units. No elevators. And all single phase. You’ll typically see about 24-40 units per building and multiple single-phase meter banks on a building. So for instance a 24 unit building would have two 1200A MCB meter stacks with 12 meters each.


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I have not installed a multi wire circuit in over 10 years. Keep it simple, genius. When you consider the problems 120 volt standard circuits are cheaper.
 
curt swartz said:
In reality I think the market for 2P AFCI breakers for use on 208/120 systems is limited. They are really only necessary to retrofit situations. For new construction the solution is to not use multi-wire circuits.
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In my opinion, they should specifically not be required in retro-fit applications.
 
ramsy said:
Nevertheless, GE equipment stands to dominate this 120Y/208v residential market, if others don't start putting their stickers on GE's AFCI's.
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This is the part of your thinking I don't understand. Single pole AFCI's work fine with 208/120 systems. The need for 2P AFCI's is very limited. The only places I see 208/120 used for residential is mid to large apartment and mixed use buildings. 99% of the units are <800 sqft so multi-wire circuits don't provide any advantage.

Even for single family dwelling's I have never used a 2P AFCI and don't think I have seen one installed. The suppliers I deal with only keep a few 2P AFCI's in stock compared to 1000's of single pole.

The only real need for 2P AFCI's are retro fit situations. In most cases when apartments get simple kitchen/bath remodels the property manager never gets permits so AFCI's don't get installed. When old units get major remodels they are usually rewired so multi-wire circuits are not used.
 
curt swartz said:
This is the part of your thinking I don't understand...The only real need for 2P AFCI's are retro fit situations..
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My service business is existing wiring, in old residential buildings with lots of MWBC's on both 1ph 240v, and 3ph 120Y/208.

If 3ph 120Y/208v distributions are gone, I wouldn't have noticed.

Shutting down MWBC's before repair works fine for me. I understand others are fired, and whipped with Romex for wasting time to shut down, much less waste time to remove drywall rocks from the boxes.
 
GE is trash, there's no way I'm using it just because it doesn't have gfpe. I'll continue to skip afci protection whenever possible.
 
peter d said:
GE is trash, there's no way I'm using it just because it doesn't have gfpe. I'll continue to skip afci protection whenever possible.
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Why do you say GE breakers are trash. I've seen them all fail. QO, HOM, MP, ................
 
kwired said:
by not using MWBC's for any circuits requiring AFCI protection. Singe pole AFCI's will still work on these systems.
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And not necessarily practical, but FWIW a three phase AFCI breaker with one phase unused might work in this situation for a two phase MWBC. You would probably have to use a three phase panel too though.
 
brantmacga said:
Generally, apartment complexes here top out at 3 floors, and are anywhere from 100-800 units. No elevators. And all single phase. You’ll typically see about 24-40 units per building and multiple single-phase meter banks on a building. So for instance a 24 unit building would have two 1200A MCB meter stacks with 12 meters each.


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POCO's don't encourage using three phase if anything for load balancing reasons? How many have electric heat and water heating?

GoldDigger said:
And not necessarily practical, but FWIW a three phase AFCI breaker with one phase unused might work in this situation for a two phase MWBC. You would probably have to use a three phase panel too though.
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Other than using GE's AFCI's does anyone have a three pole AFCI? If so probably only ever considered for retrofit applications.
 
kwired said:
POCO's don't encourage using three phase if anything for load balancing reasons? How many have electric heat and water heating?
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Gas furnaces are extremely rare at least in my area of the south.

Gas water heaters are rare in residential here. I see gas furnaces and water heaters in maybe 20% of the commercial work I do in the northern areas of Georgia and Alabama. It’s non-existent in my work in Florida.

As far as apartment complexes go, I don’t know if any in my area using gas.



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brantmacga said:
Gas furnaces are extremely rare at least in my area of the south.

Gas water heaters are rare in residential here. I see gas furnaces and water heaters in maybe 20% of the commercial work I do in the northern areas of Georgia and Alabama. It’s non-existent in my work in Florida.

As far as apartment complexes go, I don’t know if any in my area using gas.



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Not that I do many apartments, but I think is common for them to be all electric here as well, owners don't care what utility bills are, electric heat/water heating is less cost to install and maintain.
 
Hey I really appreciate all the help. The Inspector said it’s becoming a problem in the area and suggested the following, but also stated he wasn’t sure if it will work. What do you guys think about doing it this way for a 120/208

8440cca270217e333f719dad08284f69.jpg



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That won't work at all and makes no sense electrically. That guy is an inspector and he suggested that?:?:roll: I doubt he's done electrical work one day in his life.
 
peter d said:
That won't work at all and makes no sense electrically.
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Why won't an OBC AFCI / GFCI (dual function), at the first outlet of a two-wire 120 V 20 A branch circuit work?

Cybatrex said:
Hey I really appreciate all the help. The Inspector said it’s becoming a problem in the area and suggested the following, but also stated he wasn’t sure if it will work. What do you guys think about doing it this way for a 120/208?
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Here's my take. Your inspector has seen the job site and suggested a solution from 2014 NEC 210.12(B). Next to you, he's the most informed about the nature of the work you have done on the wiring system in this dwelling.

Your inspector is telling you that it is OK with him / her that the multiwire portion of the branch circuit not be protected with AFCI. And you are being allowed to treat the branch circuit as a "modified, extended or altered" branch circuit.

In my opinion, this is a big hurdle that you have cleared.

Place the Outlet Branch Circuit (OBC) dual function AFCI / GFCI at the end of the Multiwire run, farthest away from the two-pole 20 A breaker, and protect the pair of two-wire branch circuits that continue on "downstream" from that point.

This is a perfectly workable, and electrically sound, solution.
 
First of all I thought you had a miltiwire branch circuit from the panel. If so I think your only legitimate code compliant solution is to install a OBC AFCI nippled of the panel, or use another accepted conduit, then plain OBC AFCI and a regular GFCI at the location necessary.
 
Sierrasparky said:
First of all I thought you had a miltiwire branch circuit from the panel. If so I think your only legitimate code compliant solution is to install a OBC AFCI nippled of the panel, or use another accepted conduit, then plain OBC AFCI and a regular GFCI at the location necessary.
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Sierra, if I've understood Cybatrex, there is a MWBC extending from the two-pole 20 A overcurrent protective device. So you are correct about that.

From the notes (above in the sketch), rather than force the replacement of the MWBC with a new pair of two-wire runs, the inspector is saying it is acceptable to put the OBC AFCIs where the shared neutral ends.

Now, if the MWBC shared neutral portion on the branch circuit was not part of the scope of Cybatrex' work, 2014 NEC 210.12(B) makes sense, where the "first receptacle outlet of the existing branch circuit" is the one CLOSEST to the split of the shared neutral into a pair of two-wire unshared neutral extensions.
 
al hildenbrand said:
Why won't an OBC AFCI / GFCI (dual function), at the first outlet of a two-wire 120 V 20 A branch circuit work?



Here's my take. Your inspector has seen the job site and suggested a solution from 2014 NEC 210.12(B). Next to you, he's the most informed about the nature of the work you have done on the wiring system in this dwelling.

Your inspector is telling you that it is OK with him / her that the multiwire portion of the branch circuit not be protected with AFCI. And you are being allowed to treat the branch circuit as a "modified, extended or altered" branch circuit.

In my opinion, this is a big hurdle that you have cleared.

Place the Outlet Branch Circuit (OBC) dual function AFCI / GFCI at the end of the Multiwire run, farthest away from the two-pole 20 A breaker, and protect the pair of two-wire branch circuits that continue on "downstream" from that point.

This is a perfectly workable, and electrically sound, solution.
Click to expand...

This is also the same inspector that told me to put the AFCI Breaker on there not knowing it would work in that system. I’m a little apprehensive because I’ve been through 6 breakers at $120 each.


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