AFCI BREAKER PROBLEM - NEED CONFIRMATION.

[Cybatrex]

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.

It is a multi wire but on a 208 system
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[Cybatrex]

By the way it's a "pole", not a "pull".

Siri misunderstood me.


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[Cybatrex]

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.

This is the recommendation, why won’t it work? Help me to understand why.


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[augie47]

If the problem is the "GF" function in the Square CAFCI breaker, do their GF 2 pole breakers have the same restriction ?

 

[augie47]

This is the recommendation, why won’t it work? Help me to understand why.


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I see no reason it would not work as long as it is installed per 210.12(A)(5) restrictions.
I'l also await the answer as to "why not"

 

[al hildenbrand]

If the problem is the "GF" function in the Square CAFCI breaker, do their GF 2 pole breakers have the same restriction ?

The SqD two-pole CAFCI is actually labeled as not allowed to be powered by a 208Y/120 Volt supply (see the OP photo of the actual SqD Breaker.) The problem is not the ground fault sensing. See the Installation Instructions for SqD two-pole GFCI and you will note they are approved for 208Y/120 Volt installation.

Thank you Wayne, you are correct. My explanation about the ground fault sensing component in the AFCI being to blame is wrong.


I agree that the "black box" is where the incompatibility has to be coming from.


Yes.

View attachment 21859

Augie, the "black box" is the Arc Fault sensing component of the SqD CAFCI.

 

[al hildenbrand]

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.

What your diagram shows is, in essence, exactly the same as using two single pole Dual Function GFCI / AFCI breakers with only two-wire (with equipment ground conductor -- EGC) on the LOAD side of the single pole breakers. -- You could do that with your existing SqD panel, use two single pole CAFCI if you removed the three-wire shared-neutral branch circuit and installed a pair of two-wire branch circuits.

The difference in your situation is that the inspector having authority in your jurisdiction has said you can leave the Multiwire portion of the Branch Circuit without AFCI protection.

On the electrical theory side of the OBC Dual Function AFCI / GFCI in your diagram: Each OBC Dual Function AFCI / GFCI "sees" only 120 V, Line to Neutral, and "does not see" the 208 V Line to Line with its phase angle. This will absolutely work.

 

[Cybatrex]

I rigged it to test. I placed a GFCI 20 2 POLE in the box and right after into two separate AFCI OUTLETS. No problem it works great. When I test the circuit downstream I’m reading 82v. Why such a large voltage drop, the lower voltage is causing the AFCI OUTLET LED TO RED.

Any ideas?


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[Cybatrex]

What your diagram shows is, in essence, exactly the same as using two single pole Dual Function GFCI / AFCI breakers with only two-wire (with equipment ground conductor -- EGC) on the LOAD side of the single pole breakers. -- You could do that with your existing SqD panel, use two single pole CAFCI if you removed the three-wire shared-neutral branch circuit and installed a pair of two-wire branch circuits.

The difference in your situation is that the inspector having authority in your jurisdiction has said you can leave the Multiwire portion of the Branch Circuit without AFCI protection.

On the electrical theory side of the OBC Dual Function AFCI / GFCI in your diagram: Each OBC Dual Function AFCI / GFCI "sees" only 120 V, Line to Neutral, and "does not see" the 208 V Line to Line with its phase angle. This will absolutely work.

It does work but now getting under voltage readings downstream.



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[Cybatrex]

Solved. Neutral was loose. All works great. Thank k you everyone so much for your help. It’s very appreciated


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[al hildenbrand]

I rigged it to test. I placed a GFCI 20 2 POLE in the box and right after into two separate AFCI OUTLETS. No problem it works great. When I test the circuit downstream I’m reading 82v. Why such a large voltage drop, the lower voltage is causing the AFCI OUTLET LED TO RED.

Any ideas?

First: The Leviton OBC AFCI LOAD side neutrals seem to be jumpered together. The LOAD neutral of each OBC AFCI has to be kept separate along its entire length.

Here: Check against Figure 7B on This Installation Instruction Sheet

To be clear, as your sketch shows, the LINE side neutrals CAN be tied together to the shared neutral of the MWBC.

 

[peter d]

I know I'm reviving a zombie thread here, but is that THHN wire in conduit I'm seeing here? Those look like ENT/smurf connectors which suggests a raceway to an island in a concrete slab. If so, you could have pulled additional circuits in that conduit and avoided this problem all together.

 

[Cybatrex]

I know I'm reviving a zombie thread here, but is that THHN wire in conduit I'm seeing here? Those look like ENT/smurf connectors which suggests a raceway to an island in a concrete slab. If so, you could have pulled additional circuits in that conduit and avoided this problem all together.

You are correct it’s a combo of both but they were already existing. I added 2 circuits to the kitchen and left the multi wires alone not realizing it would be such a pain.


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[mlnk]

I have not installed a multi wire circuit in over 15 years. Why ask for trouble?

 

[GeorgeB]

I have not installed a residential multi wire circuit in over 15 years. Why ask for trouble?

None of your residences have panels fed from other panels (subpanels?) I'm a lowly engineer working in industrial system, but see that often. Indeed, my home has 2.

Or do you mean branch circuits vs feeders? A MWBC is moderately common here supplying power to detached garages.

 

[Adamjamma]

I use conduit a lot in Jamaica. It would save money, in the cost of the whole house install, to share the neutral. Yet I always pull two neutrals, two live and a ground... have often wondered if a second ground might be better but.. since I pull a full size ground, I dont think it really matters.

I always tape the two wires that are paired as well, to keep track of them. More common in my installs of the past five years in Jamaica has been the use of Red/Black for pair one, and Brown/Blue for pair two... since Jamaica uses the British old colors, and we are allowed to remark at the ends. Inspectors actually like my method as it is easier for them and I to keep track of circuits in the conduits, and follow them to the breakers, if the labels fall off.

But, very seldom do I use any wires in Cables, such as 12-2 or 12-3... and when I used to do that in the USA, I always ran it as 12-2.. because my boss hated running 12-3 and sharing neutrals.. insisted it was better to run the two cables from the panel, and that it cost him less money in the long run.
Only 14-3 we ran was for the light switches..lol

 

[readydave8]

I'm not as opposed to multi-wire circuits as many seem to be

and sometimes prefer when concerned about voltage drop on long runs

(AFCI circuits excepted)

 

[kwired]

I'm not as opposed to multi-wire circuits as many seem to be

and sometimes prefer when concerned about voltage drop on long runs

(AFCI circuits excepted)

Same here. AFCI's make them more impractical, handle tie rules were added for protecting those that have no business working on the circuit as well, let them burn up equipment if they open the neutral and learn to call someone that knows what they are doing:happyyes: I don't have so much issue with handle tie when both ungrounded conductors land on same outlet device, which once was about the only handle tie rule.