# I doubt this is legal, but why?



## BBQ (Nov 16, 2010)

jcarr719 said:


> I have a dedicated 40A 240v circuit + neutral + ground that originally fed a oven/microwave combination unit. The microwave part of the combo unit was internally wired to use one of the 120v hots and neutral. Connection was hard-wired in a J-Box in the cabinet.
> 
> I want to replace the combination unit with a single oven and separate microwave. The oven is 40A 240v (direct wire) while the microwave is 15A 120v (5-15) plug.
> 
> ...


No not legal.

As far as why it is because you are not allowed to supply a 15 or 20 amp receptacle with 40 amps 

Furthermore I am sure the micro specifies a 15 or 20 amp circuit, not a 40, that would be a 110.3(B) violation. 


As far as being functionally the same that means nothing.


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## Maple_Syrup25 (Nov 20, 2012)

take an 8awg lead of of one of the hots (after the 40A recp) and put an inline fuse in at 15a run a 14/2 to your microwave and enjoy your popcorn.


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## BBQ (Nov 16, 2010)

Maple_Syrup25 said:


> take an 8awg lead of of one of the hots (after the 40A recp) and put an inline fuse in at 15a run a 14/2 to your microwave and enjoy your popcorn.


That would not be NEC compliant. 

An inline fuse does not meet the requirements for branch circuit protection. 

He could run the feed into a sub panel and go that route.


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## Maple_Syrup25 (Nov 20, 2012)

BBQ said:


> That would not be NEC compliant.
> 
> An inline fuse does not meet the requirements for branch circuit protection.
> 
> He could run the feed into a sub panel and go that route.


i was just kidding fella, it would protect it though! either an inline fuse or fuse holder and some din rail :thumbsup:


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## jcarr719 (Aug 1, 2012)

Thanks. That's what I figured. 

Could I replace the J-box with a small surface mount load center fed from the 40A ckt? Then hardwire the oven pigtail directly to the 40A dual breaker & LC neutral bus. Add a 15A single breaker to a 5-15 recep in a nearby J-Box. Or would the oven need a separate J-box outside the LC?


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## Big John (May 23, 2010)

If you don't need 40A, why not just swap the breaker out...?


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## BBQ (Nov 16, 2010)

Big John said:


> If you don't need 40A, why not just swap the breaker out...?


He still wants to power an oven.


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## Bugz11B (May 12, 2013)

BBQ can he do a "tap"?? 240.21(A)--210.19--table 210.24 
(Not being a smart ass, I have never used a "tap rule" so im unsure if it conflicts with other articles, but I have heard of something similar being done)


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## BBQ (Nov 16, 2010)

Erik.Schaeffer said:


> BBQ can he do a "tap"?? 240.21(A)--210.19--table 210.24
> (Not being a smart ass, I have never used a "tap rule" so im unsure if it conflicts with other articles, but I have heard of something similar being done)


Legitimate question for sure, but no for the reasons I gave above.

The listing of the microwave and the NEC restriction of what we can supply a receptacle with.

If the microwave was designed for hardwiring than he might be able to use the branch circuit tap rules.


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## drumnut08 (Sep 23, 2012)

jcarr719 said:


> I have a dedicated 40A 240v circuit + neutral + ground that originally fed a oven/microwave combination unit. The microwave part of the combo unit was internally wired to use one of the 120v hots and neutral. Connection was hard-wired in a J-Box in the cabinet.
> 
> I want to replace the combination unit with a single oven and separate microwave. The oven is 40A 240v (direct wire) while the microwave is 15A 120v (5-15) plug.
> 
> ...


Aside from the obvious code issues with this , I guarantee you'll be tripping breakers when the oven is cranked and fire up the microwave at the same time . It's not worth the aggravation IMO . Run a new circuit for the microwave and call it a day . Getting into taps and inline fuses is asking for trouble .


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## jcarr719 (Aug 1, 2012)

Maybe I was confusing in my earlier query. 

At the main load center, I have one 40A 2-pole circuit for the supply to these loads. (I don't want to pull new wire and have no spare breaker spaces in the main panel anyway.)

I need a 30A 2-pole for the oven (I think I said 40A earlier, but it's 30A) and 15A 1-pole for the microwave. So feed add a sub-panel inside a 24" deep kitchen cabinet above the ovens with the 40A 2-pole (no breaker in the sub-panel; just the 40A in the main) and add a 30A 2-pole + 15A 1-pole. Connect the oven pigtail DIRECTLY to the 30A breaker & neutral bus (legal? IIRC, it's stranded wire, if that matters). 

If I end up having to feed everything thru the existing 4x4 J-Box to the new sub-panel, do I have to loop the neutral (& ground) THRU the new panel or can I just "T" it in the J-Box? If I loop, I'd have 8x #8 + 3x #14; if T-ed, 6x #8 + 3x #14. If I can "T" the neutrals/grounds, do I even need to bring the neutral to the panel? (I'm sure I need the ground for safety.) What size EMT would I need for these conductors?

Also, is it legal to use wire nuts in a panel (to extend a conductor)?


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## drumnut08 (Sep 23, 2012)

jcarr719 said:


> Maybe I was confusing in my earlier query.
> 
> At the main load center, I have one 40A 2-pole circuit for the supply to these loads. (I don't want to pull new wire and have no spare breaker spaces in the main panel anyway.)
> 
> ...


So now , you want to put a small load center in a cabinet ? Why are you against running a new circuit back to the main panel , Because there is no room ? One tandem breaker and some NM will take care of this . Is it hard to get a new home run back to the main panel ?


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## guest (Feb 21, 2009)

jcarr719 said:


> Maybe I was confusing in my earlier query.
> 
> At the main load center, I have one 40A 2-pole circuit for the supply to these loads. (I don't want to pull new wire and have no spare breaker spaces in the main panel anyway.)
> 
> ...



IBTL....:whistling2:










Is this guy even an electrician? So many of the questions scream "handyman" or DIY.


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## Maple_Syrup25 (Nov 20, 2012)

the 40a breaker wouldnt trip man, especially if its just an oven no cook top. drag an 8/3 out the 4x4 box into a 4 circuit subpanel (maybe change to a 4x11 though) put the subpanel in an accesible location that isn't ugly and run your micro circuit through that. you have to bring your neutral into the sub panel for your micro anyway


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## chicken steve (Mar 22, 2011)

jcarr719 said:


> I have a dedicated 40A 240v circuit + neutral + ground that originally fed a oven/microwave combination unit. The microwave part of the combo unit was internally wired to use one of the 120v hots and neutral. Connection was hard-wired in a J-Box in the cabinet.
> 
> I want to replace the combination unit with a single oven and separate microwave. The oven is 40A 240v (direct wire) while the microwave is 15A 120v (5-15) plug.
> 
> ...



see 210.19(a)(3) ex #1 

~CS~


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## randas (Dec 14, 2008)

Wow! I think this may actually be a legitimate application for the "tie the microwave to the stove circuit to speed up your hotdog cooking" :laughing::thumbup:


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## Dennis Alwon (May 9, 2009)

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