Diswasher Disposal

 
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Old 10-22-2017, 12:17 AM   #1
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Diswasher Disposal


I?ve come across some receptacles in new construction that have the diswasher and disposal circuits (both dedicated) on a single receptacle. The breakers have a mutual disconnect but the receptacles are only rated for 120. There is potentially 240 between the hot terminals which leads me to believe this is wrong but it passed the building inspection. Any thoughts?
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Old 10-22-2017, 12:22 AM   #2
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Re: Diswasher Disposal


Assuming you mean a duplex (not a single) receptacle............. it's perfectly legal.

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Old 10-22-2017, 12:23 AM   #3
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Re: Diswasher Disposal


http://www.contractortalk.com/f5/can...eutral-361025/

It's not that much trouble to just separate them....I think the change should be made to the code on MWBC
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Old 10-22-2017, 12:37 AM   #4
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Re: Diswasher Disposal


So the rating on the receptacle is hot to neutral as opposed to the potential between any two points on the device? Do you have a code or manufacturer spec reference fore that?
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Old 10-22-2017, 12:38 AM   #5
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Re: Diswasher Disposal


Obviously a duplex otherwise you?d have a phase to phase fault
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Old 10-22-2017, 12:55 AM   #6
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Re: Diswasher Disposal


Each receptacle will be rated and listed for 120v. You can put one, two or even three on a single yoke. Check section RTDV of the UL White Book.

Quote:
Duplex receptacles rated 15 and 20 A that are provided with break-off
tabs may have those tabs removed so that the two receptacles may be
wired in a multi-wire branch circuit or multiple branch circuits.




A line-to-line fault will still be cleared by a properly-installed overcurrent device.
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Last edited by 480sparky; 10-22-2017 at 12:57 AM.
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Old 10-22-2017, 01:03 AM   #7
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Re: Diswasher Disposal


I'm confused. I'm not talking about multiple wires being tied into one receptacle. I'm talking about two dedicated circuits on one receptacle. Code requires those to have a mutual disconnect which in most modern panel leads to opposite phases. Therefore the potential between the hot terminals on the receptacle is 240 or 208 in certain situations. My question is why does that not violate the 120 listing for receptacles?
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Old 10-22-2017, 01:05 AM   #8
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Re: Diswasher Disposal


You are only applying 120v to a each receptacle.
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Old 10-22-2017, 01:52 AM   #9
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Re: Diswasher Disposal


A duplex by definition is a multiple receptacle.

Maybe this article will help.

http://www.ecmag.com/section/codes-s...nch-circuits-0

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Old 10-22-2017, 02:25 AM   #10
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Re: Diswasher Disposal


Very good article however I didn?t see any mention of opposite phase circuits on the same device. I agree a duplex device has two receptacles but with two circuits that have a mutual disconnect you?ve got 240 across the hot terminals. The device is not listed for that potential. What am I missing?
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Old 10-22-2017, 09:09 AM   #11
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Re: Diswasher Disposal


Quote:
Originally Posted by Hotneutral View Post
............ The device is not listed for that potential. ...........
Yes, it is. See post 6.



Quote:
Originally Posted by Hotneutral View Post
.........What am I missing?
A 240v load.




You're overthinking this. It's not an issue. Never has been.
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Last edited by 480sparky; 10-22-2017 at 09:44 AM.
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Old 10-22-2017, 09:35 AM   #12
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Re: Diswasher Disposal


Quote:
Originally Posted by Hotneutral View Post
Very good article however I didn?t see any mention of opposite phase circuits on the same device. I agree a duplex device has two receptacles but with two circuits that have a mutual disconnect you?ve got 240 across the hot terminals. The device is not listed for that potential. What am I missing?
You're looking at the contact/connection points in the duplex as a pair of contact/connection points, they're not. Each opening/side is an individual contact point. This is no different than 2 single round 120v receptacles in an outlet (box).

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Old 10-22-2017, 09:42 AM   #13
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Re: Diswasher Disposal


Quote:
Originally Posted by tjbnwi View Post
You're looking at the contact/connection points in the duplex as a pair of contact/connection points, they're not. Each opening/side is an individual contact point. This is no different than 2 single round 120v receptacles in an outlet (box).

Tom
Same logic applies to a pair of one-pole breakers in the panel.

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