GFCI - MWBC - GD, DW, SBAC

E

ESolar

Senior Member
Location
Eureka, CA Humboldt County
Occupation
Electrician/Contractor
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.
Click to expand...
But for existing it may make sense to have them rather than run a new circuit.
 
kwired

kwired

Electron manager
Location
NE Nebraska
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.​

Click to expand...
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.
 
E

ESolar

Senior Member
Location
Eureka, CA Humboldt County
Occupation
Electrician/Contractor
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.
Click to expand...
Not when the circuits are existing and you're upgrading the breakers.
 
G

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
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.
Click to expand...
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.
 
kwired

kwired

Electron manager
Location
NE Nebraska
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.
Click to expand...
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.
 
E

ESolar

Senior Member
Location
Eureka, CA Humboldt County
Occupation
Electrician/Contractor
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.
Click to expand...
A 3/4 HP GD and standard DW are 20A combined by design. Very unlikely to blow the breaker or overheat the wire.
 
kwired

kwired

Electron manager
Location
NE Nebraska
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.
Click to expand...
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.
 
W

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
kwired said:
So the methane just ends up being produced in a different location, right?
Click to expand...
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
 
E

ESolar

Senior Member
Location
Eureka, CA Humboldt County
Occupation
Electrician/Contractor
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.
 
R

retirede

Senior Member
Location
Illinois
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.
Click to expand...

Did it trip on arc fault or overload?
 
You must log in or register to reply here.
Top