New Code suggestion on built-in microwaves

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jeff48356

Senior Member
I realize it's too late for a 2020 Code suggestion, but with all the miswired microwave ovens I've run into lately, i.e. people using 14/2 from range hood to power them and therefore frequently tripping the breaker, I would have liked to propose a new Code rule about them. I would have said that a built-in microwave oven must have a separate 20A circuit run to it, with a receptacle outlet in the back of the cabinet over the range under which it is mounted. Also, there could be no other loads on this circuit except for the outlet used to power a gas range (lights, clock, ignition, etc.). Any thoughts on this? In my opinion, it should have been added decades ago when over-the-range microwaves became commonly used.
 

jumper

Senior Member
You are seeing a lot of micro- hood combos tripping the breaker of a 15A individual circuit?

I find that unusual.

You do realize that all plug and cord connected units already require an individual circuit. 422.16(B)(4).
 

jeff48356

Senior Member
You are seeing a lot of micro- hood combos tripping the breaker of a 15A individual circuit?

I find that unusual.

You do realize that all plug and cord connected units already require an individual circuit.

No, these are all 15A lighting circuits. They typically wired the range hood to one of the general-purpose lighting circuits back in the day, and kitchen remodelers who are clueless about electrical loads would often take the 14/2 cable that used to feed the range hood and use it to power the microwave. You can't do that!
 

jumper

Senior Member
No, these are all 15A lighting circuits. They typically wired the range hood to one of the general-purpose lighting circuits back in the day, and kitchen remodelers who are clueless about electrical loads would often take the 14/2 cable that used to feed the range hood and use it to power the microwave. You can't do that!

I know all this. My point is that code covers this already, except that the circuit does not have to be 20A.
 

jeff48356

Senior Member
I know all this. My point is that code covers this already, except that the circuit does not have to be 20A.

OK, good! I'll look it up. Now I wish more remodelers would follow the rules when doing kitchens. It's obvious that they're trying to save money by not using licensed electricians to do the wiring. Then the customer complains about breakers tripping, and they end up calling me to run a new circuit when it would have been a lot easier (and cheaper) during the renovation.
 

jumper

Senior Member
OK, good! I'll look it up. Now I wish more remodelers would follow the rules when doing kitchens. It's obvious that they're trying to save money by not using licensed electricians to do the wiring. Then the customer complains about breakers tripping, and they end up calling me to run a new circuit when it would have been a lot easier (and cheaper) during the renovation.

I put the code reference above, but again 422.16(B)(4).

The remodeling crew is the problem, not the NEC in this scenario. They are in violation.
 

Adamjamma

Senior Member
Truth is, the remodeling company is going to take the attitude that the wire is there, it is 14, which can power a 15 amp circuit, so it should work just fine. Kitchen companies try to do nothing that needs an electrician just so they can get away with not needing an electrical permit...

There is nothing in the code about requiring a new single circuit to be run if one is remodeling, and most of the code is only concerned with first install, and says you do not need to change circuits if already there unless the change is easy, basically... in other words, just because no ground was run to an outlet when it was built to code does not mean it needs upgraded to the new code now...

But where it is easy to do so because the walls are open, or you are doing a rebuild after a fire or a flood, it is then easier to bring the building up to the new codes, which triggers the above clause concerning plug outlets being single run for built n appliances...

However, now I know where to go for my own request for an amendment..lol
 

JFletcher

Senior Member
Location
Williamsburg, VA
I feel your pain... Kitchen remodels are probably my least favorite part of electrical work... It is infuriating to have a homeowner brag about his new $10,000 tiger quartz countertop from some unheard-of rare quarry in Italy and in the same sentence complain about a $20 required GFCI.

kitchens are also one of the few areas in homes where something installed 5 years ago may not be up to current code.

as far as your particular violation, I do not run across that very often, much more often I run across lighting circuits jumped off the SABC, and impossibly overfilled switch boxes.
 

480sparky

Senior Member
Location
Iowegia
Many over-the-range microwaves in older kitchens started out as just hoods. So the requirements for just a 60w lamp and small fan motor was minimal. Then the hood was removed during a remodel and the micro installed. Gee, there's power right here..... Let's use that!
 

jumper

Senior Member
Many over-the-range microwaves in older kitchens started out as just hoods. So the requirements for just a 60w lamp and small fan motor was minimal. Then the hood was removed during a remodel and the micro installed. Gee, there's power right here..... Let's use that!

Yes but that is a violation and another rule is not going to fix the problem IMO.

IMO the NEC already addresses this problem and I see no need for the circuit to be 20A unless needed.
 

Adamjamma

Senior Member
kitchens are also one of the few areas in homes where something installed 5 years ago may not be up to current code.

as far as your particular violation, I do not run across that very often, much more often I run across lighting circuits jumped off the SABC, and impossibly overfilled switch boxes.

OK: as far as connecting lights to the SABC it seems to be allowed under 210-52-B-1 exception 1... which refers to 210.70.A exc 1, which basically says that the switch has to control a light outlet and cannot control a outlet to plug in lights...
which to me means that you cannot decide the room lighting is covered because you set up wall outlets controlled by the light switch for the owner to put their own floor lights into but you must provide lighting in the ceiling or the walls that is permanent mounted.

Unless I am reading the codes wrong, because Exception 1 was to the rule that says no other outlets on the SABC, which specifically seems to allow running lights to the SABC...
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
While we all encourage writing PI's to make changes to the NEC your change must be something that is based on a real world problem that hasn't already been addressed by the code. The NEC has requirements for built-in microwaves if the trunk slammers aren't following the code added another layer of requirements will accomplish nothing. Furthermore as others have echoed I see no need to require a 20 amp circuit for a microwave that is permitted on a 15 amp circuit. If it requires a 20 amp circuit then there are already code sections in place to make it code complaint.
 

sameguy

Senior Member
Location
New York
Occupation
Master Elec./JW retired
Take the job and run to the bank!
Our resi. industry is a one shot deal, see you in 20 yrs.!
 

peter d

Senior Member
Location
New England
You are seeing a lot of micro- hood combos tripping the breaker of a 15A individual circuit?

I find that unusual.

You do realize that all plug and cord connected units already require an individual circuit. 422.16(B)(4).

I have never seen it. A microwave comes with a 15 amp cord cap anyway.
 

GeorgeB

ElectroHydraulics engineer (retired)
Location
Greenville SC
Occupation
Retired
Also, there could be no other loads on this circuit except for the outlet used to power a gas range (lights, clock, ignition, etc.).

Unrelated to your point, but my gas range has a "warmer" which is resistance heat from that 120V circuit ... 5A if IIRC. (Oh, and the builder did share it with the built-in microhood) We don't use the warmer, rather storing oven pans in the drawer.
 

JFletcher

Senior Member
Location
Williamsburg, VA
OK: as far as connecting lights to the SABC it seems to be allowed under 210-52-B-1 exception 1... which refers to 210.70.A exc 1, which basically says that the switch has to control a light outlet and cannot control a outlet to plug in lights...
which to me means that you cannot decide the room lighting is covered because you set up wall outlets controlled by the light switch for the owner to put their own floor lights into but you must provide lighting in the ceiling or the walls that is permanent mounted.

Unless I am reading the codes wrong, because Exception 1 was to the rule that says no other outlets on the SABC, which specifically seems to allow running lights to the SABC...

210.52(B)(2) exception two does not cover any hardwired lights. Even if one can ignore 50 watts of LED recessed lighting on the small appliance branch circuit, the bigger problem is often the lights are wired with 14 gauge and jumped off a 20 amp circuit.

210.52(B)(1) exception 1 does not allow for permanently installed lighting to be on the SABC.

"No other outlets" includes light fixtures per the article 100 definition of an outlet.
 

Adamjamma

Senior Member
210.52(B)(2) exception two does not cover any hardwired lights. Even if one can ignore 50 watts of LED recessed lighting on the small appliance branch circuit, the bigger problem is often the lights are wired with 14 gauge and jumped off a 20 amp circuit.

210.52(B)(1) exception 1 does not allow for permanently installed lighting to be on the SABC.

"No other outlets" includes light fixtures per the article 100 definition of an outlet.
Exception 1 specifically refers you to the other code concerning lights that says in kitchens you cannot use a switched receptacle for lights. Thus, exception one is allowing you to put the kitchen lights on the sabc. Just not allowed to use plug in lights... or the exception one would not send you to switches for lighting circuits.
 

peter d

Senior Member
Location
New England
Let's see if I got this straight. Free standing microwave on counter plugged into SABC - just fine. Built in microwave tapped off of SABC - no good. :?
 
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