dedicted circuit for microwave?

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Joseph Alexander

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I know most of will think this is a dumb question, but is a dedicated circuit really needed for a mounted microwave (kitchen) most AHJs require this, but I can't find a specific code which covers this? I say specific because Microwaves are not mentioned in the code at all. They've been around for 50years why are they not mentioned? I would appreciated any help with a code #:-?
 
If it serves as a range hood and is cord and plug connected it needs a separate circuit. Look at 422.16(B)(4)(5).
 
Trevor, does a over-range microwave fall under this section?
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Joe, whether the discussion shows that it does or not, it falls under the general rules for permissible loads in 210.23, which you might take a close look at.
 
jimport said:
If nothing else the manufacturers installation instructions call for the dedicated circuit.
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Some of the manufacturers installation recommend a separate circuit but they do not require one.

Yesterday I went to hook up an under counter ice maker and an under counter refrig. The nameplate on the ice machine was 3 amps. The instructions actually recommended a separate circuit. The under counter refrigerator was 3.3 amps. Can you guess how they got wired.
 
I am also curious as to why the range hood / microwave would not fall into the category of art. 422.16(B)(4). It is a range hood and it is cord and plug connected.

Don Hursey, the man who recommended the change to the CMP, wanted a separate circuit on cord and plug hoods specifically because of the microwave range hoods combs.
 
Dennis Alwon said:
Some of the manufacturers installation recommend a separate circuit but they do not require one.

Yesterday I went to hook up an under counter ice maker and an under counter refrig. The nameplate on the ice machine was 3 amps. The instructions actually recommended a separate circuit. The under counter refrigerator was 3.3 amps. Can you guess how they got wired.
Click to expand...

My guess is NM cable.
 
The OP makes a good point, I have lots of jobs that have a space in the cabinets for the micro to be built in. They are not micro-hood units. I put them on there own circuit just because it makes sense to. But is it required?
 
Dennis Alwon said:
Some of the manufacturers installation recommend a separate circuit but they do not require one.

Yesterday I went to hook up an under counter ice maker and an under counter refrig. The nameplate on the ice machine was 3 amps. The instructions actually recommended a separate circuit. The under counter refrigerator was 3.3 amps. Can you guess how they got wired.
Click to expand...


The other day I looked at the instructions for a gas oven/ cooktop range. The instructions required a dedicated 15 amp circuit for the 120 volt receptacle required for the spark plugs and controls. My guess is the load comes to something with a decimal point before the number starts. Hope they used factory wire sized appropriate to the ocpd rather than the load when making this appliance.
 
I don't think they are required on a dedicated circuit, if it is a fixed appliance wouldn't it be considered a fix appliance??

I wired one the other day that was either a counter top or a fixed ,if fixed they required an individual branch circuit rated @15 amps. if counter top plug it in any where. The other funny thing about this unit was, it is not to be used within 2 feet of an oven or cook top, I can't for the life of me figure that one out. Unless the plastics used melt at low temps???
 
georgestolz said:
Trevor, does a over-range microwave fall under this section?
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Joe, whether the discussion shows that it does or not, it falls under the general rules for permissible loads in 210.23, which you might take a close look at.
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It falls under 422.10(B) which refers you to 210.23 if there is more than one load servered by circuit neither load can exceed 50 percent which would generally require an individual circuit to a microwave that is fasten in place.
 
I'd guess that we need to go back to the OP and decipher what a "mounted" microwave is. When I hear that term I think of a cord and plug connected microwave with an integral range hood. That type would require a dedicated circuit. I can't recall ever seeing a standard microwave that was "mounted", although they may exist.

422.16(B)(4) Range Hoods. Range hoods shall be permitted to be cord-and-plug connected with a flexible cord identified as suitable for use on range hoods in the installation instructions of the appliance manufacturer, where all of the following conditions are met:
(1) The flexible cord is terminated with a grounding-type attachment plug.
Exception: A listed range hood distinctly marked to identify it as protected by a system of double insulation, or its equivalent, shall not be required to be terminated with a grounding-type attachment plug.
(2) The length of the cord is not less than 450 mm (18 in.) and not over 900 mm (36 in.).
(3) Receptacles are located to avoid physical damage to the flexible cord.
(4) The receptacle is accessible.
(5) The receptacle is supplied by an individual branch circuit.
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Trevor,

Is a combo Micro UL Listed as a range hood, Microwave, both...neither?

I am just asking as the listing is IMO what tells us if it is a 'range hood'.
 
I just went and looked at mine....it appears to be listed as a "Household microwave oven".

That being the case IMO 422.16 does not apply. (at least to mine)
 
iwire said:
I just went and looked at mine....it appears to be listed as a "Household microwave oven".

That being the case IMO 422.16 does not apply. (at least to mine)
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So it isn't used as a range hood? If so, I'm wondering why we even need 422.16(B)(4). It seems like that particular article was written with a combo range hood/microwave in mind.
 
infinity said:
So it isn't used as a range hood?
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I did not say that, I said it is not a 'Range Hood' it is a Microwave.


If so, I'm wondering why we even need 422.16(B)(4). It seems like that particular article was written with a combo range hood/microwave in mind.
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Indulge me for a minute here.

First I think the whole idea of 422.16(B)(4) is wrong, the CMP is trying to wire for the future.

That said IMO they decided if a cord and plug 'range hood' is being installed today that sometime in the future a cord and plug micro might be installed there. As that micro is non existent now we have no idea if it will need a 15 or 20 amp circuit so they said 'provide a 20'

On the other hand if the micro is going in today we will be able to look at it and apply the normal branch circuit rules and provide the size circuit it needs.

One final thought, if the listing is not what counts can I install a CFL in a porcelain key less in a closet?

Did the addition of a CFL change the incandescent fixture into a fluorescent fixture?

By the same token does the addition of a fan to a microwave change it into a range hood?

JMO, Bob
 
I don`t know about others but, when roughing in a kitchen I pull 6 circuits to them all.2 SA, 1 micro,1 d/w, 1 disp., 1 fridge.If it is a small tract home I might hit the d/r receps off of the fridge circuit but that is the limit.
 
iwire said:
By the same token does the addition of a fan to a microwave change it into a range hood?

JMO, Bob
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Well if it contains a fan designed to used as a range hood does the fact that the label on the side of the unit that doesn't call it a range hood really matter? IMO if you argued that point (label says microwave) with an inspector you would lose every time.

Also I agree with you on the fact that the code is forcing us to wire for the future. We've had this discussion before. This seems to be one of only times that the code is requiring something based on a "what if" future situation.
 
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