Dishwasher/Disposal 3-wire circuit to duplex

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wondervamp

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Shop technician
Hello,

When installing th duplex receptacle for a dishwasher/disposal,running a 12/3 and sharing the neutral at the plug and of course breaking the tab on the hot terminal,I NEED to use a double pole 20A breaker for OCP as opposed to 2 single pole 20A breakers for each circuit? I need 240V potential between the 2 circuits I'm thinking otherwise I could overload neutral?

Thanks

Wvamp
 
wondervamp said:
Hello,

When installing th duplex receptacle for a dishwasher/disposal,running a 12/3 and sharing the neutral at the plug and of course breaking the tab on the hot terminal,I NEED to use a double pole 20A breaker for OCP as opposed to 2 single pole 20A breakers for each circuit?
Click to expand...

Yes. Since this a MWBC a two pole CB or a handle tie on two single pole CB's is required.

wondervamp said:
I need 240V potential between the 2 circuits I'm thinking otherwise I could overload neutral?

Thanks

Wvamp
Click to expand...

Yes.
 
Sombodys going to say it so might as well be me. Save yourself a few bucks and run 14/3 instead of 12.
 
single 20 amp circuit

single 20 amp circuit

Why not just run these on a single 20 amp circuit? As long as the load of the dishwasher is not over 10 amps there should be no problem.
 
wondervamp said:
Hello,

When installing th duplex receptacle for a dishwasher/disposal,running a 12/3 and sharing the neutral at the plug and of course breaking the tab on the hot terminal,I NEED to use a double pole 20A breaker for OCP as opposed to 2 single pole 20A breakers for each circuit? I need 240V potential between the 2 circuits I'm thinking otherwise I could overload neutral?

Thanks

Wvamp
Click to expand...
Depending on which code cycle you are on - you would need to use a handle tied breaker for all MWBC, previous codes did not require this for the circuit itself, but just required this for items on the same yoke. i.e. using a duplex - but in codes previous to '08 it was not required for circuits that did not share a yoke on a duplex - you could use a 2G and two singles - no handle tie.

Greg1707 said:
Why not just run these on a single 20 amp circuit? As long as the load of the dishwasher is not over 10 amps there should be no problem.
Click to expand...
Has anyone found a dishwasher below 10A recently? But since it is cord connected - the 20A circuit is limited to 16A on top of that...
 
Obviously, there are different approaches to wiring the kitchen appliances. What is the advantage of the cord and plug method described in the original post vs. just hard wiring the dishwasher/disposal.

The dishwashers I have seen lately are 10 amps and disposals are 6-7 amps. I thought these could be installed on a single 20 amp circuit if hard wired?
 
could be ok , but I can never find those handle lockouts when I need them.
I just like the recep method.It's good for the HO.
 
Greg1707 said:
Obviously, there are different approaches to wiring the kitchen appliances. What is the advantage of the cord and plug method described in the original post vs. just hard wiring the dishwasher/disposal.

The dishwashers I have seen lately are 10 amps and disposals are 6-7 amps. I thought these could be installed on a single 20 amp circuit if hard wired?
Click to expand...

Cord & Plug makes a very easy disconnect. FWIW, I have probably done 400 homes, and have always run two 15A circuits, 1 for DW; 1 for Disposal.

I don't think I've ever run a 20A for any dishwasher, but always two circuits. In some of our jurisdictions we have been required hardwired both of these appliances, but I've actually begun to prefer the receptacles, when it is permitted to be installed that way.
 
Greg1707 said:
Obviously, there are different approaches to wiring the kitchen appliances. What is the advantage of the cord and plug method described in the original post vs. just hard wiring the dishwasher/disposal.
Click to expand...

The biggest advantage is not having to wait for the appliances to be installed to wire them.
 
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