Dual function breakers and multi wire circuits

[OK Sparky 93]

I’ve been using dual function breakers, just to keep the cost down a little, since they were not a couple of dollars difference.

However I’ve never done so on a multi wire circuit. Now I know why.

With that said once you touch it…..

Kitchen remod. 12/3’s everywhere. Can’t have a gfci under the sink, and who wants a dummy one on the counter.?

Now not only does it have to be afci it also has to be gfci.

Is it time to run a new circuit?

While I’m at it got to make more room in a panel that is already twinned to the max.

I guess I’ve got put a disco outside now. Can’t have those firefighters getting zapped.

We can have a gas explosion though.

 

[Little Bill]

If you get a brand of AFCI that doesn't have the GFPE in it, you can use two singles and add a handle tie. That way you could keep the MWBC. But you will need to add GFCI receptacles at the first outlet for each circuit. Of course, the brand of AFCI has to match the panel brand.

Sounds like you should have included a panel change in your bid.

 

[LarryFine]

Sounds like you should have included a panel change in your bid.

It's not too late.

 

[OK Sparky 93]

If you get a brand of AFCI that doesn't have the GFPE in it, you can use two singles and add a handle tie. That way you could keep the MWBC. But you will need to add GFCI receptacles at the first outlet for each circuit. Of course, the brand of AFCI has to match the panel brand.

Sounds like you should have included a panel change in your bid.

Which afci breaker would you take the neutral to form the MWBC. How does that work?

I am allowing for panel swap and fresh circuits.

 

[Little Bill]

Which afci breaker would you take the neutral to form the MWBC. How does that work?

I am allowing for panel swap and fresh circuits.

The newer single pole AFCI breakers don't get the neutral connected to them.
Siemens is one such brand.

 

[OK Sparky 93]

Is that all brands? I haven’t had the need yet.
Are the dual function the same?

 

[LarryFine]

Which afci breaker would you take the neutral to form the MWBC. How does that work?

Either or neither; it can remain on the neutral bus.

 

[ramsy]

I’ve been using dual function breakers, just to keep the cost down a little, since they were not a couple of dollars difference.

AFCI and GFCI breakers eventually die without good surge protection, since subject to damage by utility excursions.

However I’ve never done so on a multi wire circuit. Now I know why.

With that said once you touch it…..

Kitchen remod. 12/3’s everywhere. Can’t have a gfci under the sink, and who wants a dummy one on the counter.?

Are you abating a remodel hazard ?

Now not only does it have to be afci it also has to be gfci.

Was not aware the disposer now requires GFCI ?

Is it time to run a new circuit?

While I’m at it got to make more room in a panel that is already twinned to the max.

Siemens makes the AFCI twin.

I guess I’ve got put a disco outside now. Can’t have those firefighters getting zapped.

Now its getting expensive, especially without bids, plans, or permits.

 

[don_resqcapt19]

Is that all brands? I haven’t had the need yet.
Are the dual function the same?

No, they are not the same. If you want to use a multiwire circuit with a dual function breaker, the breaker will have to be a 2 pole breaker.
The neutral current must flow through the breaker for the GFCI part to work.
A number of AFCIs no longer have any type of ground fault protection (all of the original AFCIs had ground fault protection) and without ground fault protection the neutral current does not have to flow through the breaker.

 

[letgomywago]

There isn't a 2 pole dualfunction in production. You can install the 2 pole afci and then do a gfi either under the sink or use a gfi switch combo for disposal ect. Other option is a gfi "feeder" nipple a small 2 space panel from the panel do 2 pole gfi to 2 space panel then 2 pole afci in the panel.

If you're not able to do gfi device under the sink plan on new home runs. That's probably the best option honestly

 

[kwired]

Is that all brands? I haven’t had the need yet.
Are the dual function the same?

GFCI feature of them won't let it work.

When they came out with those AFCI's that don't need load side neutral run through the device they found some way to pass listing requirements without also needing some level of ground fault protection incorporated into them. This ground fault level was not the 4-6 mA that GFCI requires so it couldn't be called GFCI.