micro wave tap 210.19

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how long can the tap from a 50 amp range circuit be for a 20amp circuit for a microwave? I know this has to have been discussed before but I can't find it.
 

Mouser

Member
Location
Riverside, CA.
If you are referencing the 2011 NEC then the illustration happens to show an oven and a cooktop. As previously mentioned you can't tap a 50 A. branch circuit for a MW.
 
microwave tap

microwave tap

I appreciate your input, but I have yet to hear why you can tap a cooking device but not a microwave, especially since the word microwave does not even appear in the NEC.
 

JDBrown

Senior Member
Location
California
Occupation
Electrical Engineer
how about 210.19 it specifically shows this in the handbook ex 210.21
I think that's a wall mounted oven in the handbook exhibit, not a microwave. 210.19(A)(3) Exception 1 applies to tap conductors used to connect electric cooking equipment such as ranges or ovens (I don't think microwaves qualify).

As far as I can tell, this exception is there because some ranges, cooktops and ovens come with factory installed leads, rather than with a cord. Since the leads are smaller than what would be required for a 50 amp circuit (#6 for 60 degree or #8 for 75 degree), they are considered taps. Also, any short extensions of the factory installed leads that need to be added would be part of the tap. As far as I can tell, that's all this is talking about.

Although I have to admit, I thought the same thing you did when I first looked at that exhibit in the handbook.
 

iwire

Moderator
Staff member
Location
Massachusetts
I appreciate your input, but I have yet to hear why you can tap a cooking device but not a microwave, especially since the word microwave does not even appear in the NEC.

Well to start with I am assuming this is a run of the mill cord and plug connected microwave.

If that is true it is very likely the instructions specify a 15 or 20 amp circuit, not a 50 amp circuit. That would bring 110.3(B) into it.

Next if you were to install a 15 or 20 amp receptacle for it tapped on a 50 amp circuit that would be a violtion of 210.21(B)(1).
 
Clarification

Clarification

What this discussion shows is that there needs to be a clear codification on the Microwave issue! I fail to see why after being in use for 50+ years that the code council will not address the microwave issue. All of this could be cleared up if the council would just put in writing:

A mounted microwave unit must be on a dedicated circuit.

FPN: The addition of this article does not mean that microwaves placed before this codification are exempt for this rule.

The reason I am asking about this issue is I am work towards my R-5 combination inspectors card. If I found this on an inspection I could not point to any code which prohibits this. At best the views we have discussed are our opinions. If you had to argue this point are you sure you are wright? I'm not and I have been doing this for 30+ years.
 

kwired

Electron manager
Location
NE Nebraska
You can not connect the 5-15 or 5-20 receptacle directly to a 50 amp circuit.

You possibly could use a feeder tap and proper overcurrent protection to supply this receptacle.

Someone may find a place that prohibits this though.

It definitely would be more complicated if an older (then permitted) circuit that utilized the grounded conductor for grounding the frame of the range.

I don't believe the NEC recognizes a microwave in same "cooking appliances" category as they do ranges, ovens, and cooktops.
 

Cavie

Senior Member
Location
SW Florida
What this discussion shows is that there needs to be a clear codification on the Microwave issue! I fail to see why after being in use for 50+ years that the code council will not address the microwave issue. All of this could be cleared up if the council would just put in writing:

A mounted microwave unit must be on a dedicated circuit.

FPN: The addition of this article does not mean that microwaves placed before this codification are exempt for this rule.

The reason I am asking about this issue is I am work towards my R-5 combination inspectors card. If I found this on an inspection I could not point to any code which prohibits this. At best the views we have discussed are our opinions. If you had to argue this point are you sure you are wright? I'm not and I have been doing this for 30+ years.

Simple answer is, you cant fuse a 120 volt 20 amp micro at 50 amps.
 

Cavie

Senior Member
Location
SW Florida
You can not connect the 5-15 or 5-20 receptacle directly to a 50 amp circuit.

You possibly could use a feeder tap and proper overcurrent protection to supply this receptacle.

Someone may find a place that prohibits this though.

It definitely would be more complicated if an older (then permitted) circuit that utilized the grounded conductor for grounding the frame of the range.

I don't believe the NEC recognizes a microwave in same "cooking appliances" category as they do ranges, ovens, and cooktops.[/QUOTE]

They don't. That's why they don't conceder a microwave in a motel room or a dorm room to be a kitchen even if it also has a refrigerator. Looks like a kitchen, smells like a kitchen but it's not a kitchen. :):)
 
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iwire

Moderator
Staff member
Location
Massachusetts
What this discussion shows is that there needs to be acodification on the Microwave issue! I fail to see why after being in use for 50+ years that the code council will not address the microwave issue. All of this could be cleared up if the council would just put in writing:

A mounted microwave unit must be on a dedicated circuit.

FPN: The addition of this article does not mean that microwaves placed before this codification are exempt for this rule.

The reason I am asking about this issue is I am work towards my R-5 combination inspectors card. If I found this on an inspection I could not point to any code which prohibits this. At best the views we have discussed are our opinions. If you had to argue this point are you sure you are wright? I'm not and I have been doing this for 30+ years.


210.21(B) is not an opinion it is a stone cold fact.

If you really feel the code making panel should address this than I honestly suggest you put in a code proposal for it.

I have been on these forums for about ten years and do not recall anyone feeling this section applied to microwaves.
 
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Smart $

Esteemed Member
Location
Ohio
While I agree with responses regarding run-o'-the-mill, cord-and-plug-connected microwave ovens, I do believe the discussion topic regarding built-in microwave ovens is worthy of debate...

http://www.google.com/search?source...F51mpA.O&fp=4a7c743a55275708&biw=999&bih=1151

...and there are microwave ovens that have an integral resistance-type heating element (browning, roasting, convection, whatever they decided to call it), if the question of heating-element type comes into play.

So let's focus on this type rather than the typical countertop nuke...
 

iwire

Moderator
Staff member
Location
Massachusetts
While I agree with responses regarding run-o'-the-mill, cord-and-plug-connected microwave ovens, I do believe the discussion topic regarding built-in microwave ovens is worthy of debate...

http://www.google.com/search?source...F51mpA.O&fp=4a7c743a55275708&biw=999&bih=1151

...and there are microwave ovens that have an integral resistance-type heating element (browning, roasting, convection, whatever they decided to call it), if the question of heating-element type comes into play.

So let's focus on this type rather than the typical countertop nuke...



Still cord and plug connected are they not?

That would still rule out using 210.19 because of 210.21.


That said it just seems to me that 210.19 was written before microwaves and at this point should be reworked a bit to clear things up. :)
 

kwired

Electron manager
Location
NE Nebraska
Still cord and plug connected are they not?

That would still rule out using 210.19 because of 210.21.


That said it just seems to me that 210.19 was written before microwaves and at this point should be reworked a bit to clear things up. :)
As long as microwaves have a 15 or 20 amp cord cap you are limited to 20 amps max overcurrent protection. You are correct - 210.21 is probably the biggest issue for the OP, and what he wishes to do.

I really doubt any proposal to change it so a cooking appliance with a 15 amp cord cap can be plugged into a 40 or 50 amp circuit will ever be accepted. If OP wishes to connect it to a 50 amp circuit then he needs to find one that is listed with a 50 amp plug.
 

iwire

Moderator
Staff member
Location
Massachusetts
I really doubt any proposal to change it so a cooking appliance with a 15 amp cord cap can be plugged into a 40 or 50 amp circuit will ever be accepted.

I think that is a very safe bet.

My thought about a code change would be to clarify exactly what 210.19(A)(3) applies to.
 

Smart $

Esteemed Member
Location
Ohio
Still cord and plug connected are they not?

That would still rule out using 210.19 because of 210.21.


That said it just seems to me that 210.19 was written before microwaves and at this point should be reworked a bit to clear things up. :)
Pretty much true if they are just microwave ovens. But there are crossovers using multiple cooking technologies not always plug connected... but I will note they are not necessarily called microwave ovens. They are typically called wall ovens even though they utilize microwave cooking technology.

Probably a few in this pack ...

http://products.geappliances.com/Ap...ave_Ovens&Filters=BRAND!GE$20Profile$20Series

I'm not going to do an exhaustive search trying to find one that is specifically called a microwave oven.

As I so noted in my earlier post, let's focus on ones that are hardwired, not 15/20A plug connected... to give a proper reply to the OP.
 

iwire

Moderator
Staff member
Location
Massachusetts
As I so noted in my earlier post, let's focus on ones that are hardwired, not 15/20A plug connected... to give a proper reply to the OP.

You are loosing me, as far as I could tell the OP is talking about a run of the mill microwave so I don't see how focusing on another type is going to give proper reply. :?
 

Smart $

Esteemed Member
Location
Ohio
You are loosing me, as far as I could tell the OP is talking about a run of the mill microwave so I don't see how focusing on another type is going to give proper reply. :?
Well, if that be the case, you are done posting on the matter. :p
 
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