GFCI - MWBC - GD, DW, SBAC

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jaggedben said:
2-pole AFCIs have been variously on and off the market depending on the brand. For example I'm pretty sure that Homeline used to have them but now doesn't, while Siemens was slower to bring them on but now they have them. So unless you always use the same brand they are difficult to plan around. They are also expensive and tie up capital on your shelf if they don't get used because you made a mistake counting your circuits or the client or GC changed the plan on you. It's just another strike against MWBCs, which already require more planning, material management, and knowledge.
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But for existing it may make sense to have them rather than run a new circuit.
 
ESolar said:

It looks like the Eaton BRL220CAF will work for a 1990s BR2040 panel. They are expensive, ~$116. Used for ~$80. Maybe a Siemens will work.​

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Two single pole cost around the same. Two 2 wire cables Vs three wire cable or even 12-2-2 may or may not drive a particular method higher cost depending on length of home run, but seems to be somewhat a toss up presuming you have good availability of any the products needed for a particular method.
 
kwired said:
Two single pole cost around the same. Two 2 wire cables Vs three wire cable or even 12-2-2 may or may not drive a particular method higher cost depending on length of home run, but seems to be somewhat a toss up presuming you have good availability of any the products needed for a particular method.
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Not when the circuits are existing and you're upgrading the breakers.
 
jaggedben said:
Having the GD and DW on the same circuit probably is fine most of the time ... until someone drops a fork in the GD while the DW is on the heat cycle. Just guessing, not from experience.
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No experience here either, but many GDs have a built-in thermal overload which may well trip before the breaker. It is also pretty easy to flip the switch back off immediately when you hear the feared hummmm.
 
GoldDigger said:
No experience here either, but many GDs have a built-in thermal overload which may well trip before the breaker. It is also pretty easy to flip the switch back off immediately when you hear the feared hummmm.
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I think most the time people are done with needing to use the disposer by the time the DW has any kind of significant amount of demand. Big party, Thanksgiving day, possibly the times when there could be more concern like that though I still don't think is too great of a possibility of overloading long enough to trip the breaker.
 
kwired said:
I think most the time people are done with needing to use the disposer by the time the DW has any kind of significant amount of demand. Big party, Thanksgiving day, possibly the times when there could be more concern like that though I still don't think is too great of a possibility of overloading long enough to trip the breaker.
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A 3/4 HP GD and standard DW are 20A combined by design. Very unlikely to blow the breaker or overheat the wire.
 
ESolar said:
A 3/4 HP GD and standard DW are 20A combined by design. Very unlikely to blow the breaker or overheat the wire.
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The disposer don't draw anywhere near it's nameplate rating most the time I would think. Would really need to stuff it full of things to grind to get that kind of load on it. If they have somewhat high draw when unloaded is probably because they are fairly cheap motors and have a low power factor but put some real load on them and the current probably doesn't go up much but instead power factor drops as load is added.

Dishwashers particularly newer ones don't draw much either except when heating element is in use.
 
kwired said:
So the methane just ends up being produced in a different location, right?
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Methane as the end product of microbial action on organics occurs in anaerobic conditions. With oxygen present, as in composting, the microbes will preferentially create CO2. So when you compost your food waste, you avoid the more potent greenhouse gas, and you get compost to boot.

Cheers, Wayne
 
OK - so the MWBC AFCI was working fine for a week. Then I got a call about the Cuisinart Coffee maker tripping the circuit. No repeat testing because its intermittent. The circuit has a microwave, fridge, and coffee maker on it. The report was that it tripped immediately when the coffee maker was turned on. But only one time, after using the coffee maker daily for a week. Microwave was not in use.
 
ESolar said:
OK - so the MWBC AFCI was working fine for a week. Then I got a call about the Cuisinart Coffee maker tripping the circuit. No repeat testing because its intermittent. The circuit has a microwave, fridge, and coffee maker on it. The report was that it tripped immediately when the coffee maker was turned on. But only one time, after using the coffee maker daily for a week. Microwave was not in use.
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Did it trip on arc fault or overload?
 
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