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dcd22 10-02-2007 08:39 AM

Oven/Micro Combo wiring....
Let me start by saying I am not doing the actual wiring for this. I have a licenced electrican doing it (family member) who is not available for a few days to answer this question, so I am asking here.

We ran a 10/3 with ground wire to the oven. It is on a 208v 30amp circuit (as per the spec's). I need to know the correct receptical and plug to get for the unit. I do not want to hardwire it, I want to add a cors, plug and receptical (unless there is reason not to).

Is there any more info needed to determine this?

Andy in ATL 10-02-2007 04:20 PM

I'd hard wire that sucka... but thats just me:wink: . Anyone else? I'm quessin' your electrician relative will agree with me...but i've been wrong before.

Stubbie 10-02-2007 05:26 PM

Are you sure your circuit is a 208 volt circuit? This is an odd supply voltage if a single family dwelling. If this is multi-family living then it is more likely.

You will need an appliance cord designated for use with an oven appliance. Your voltage should be 208/120 or 240/120. As most combo's the micro-wave is 120 volts. So combo units are often dual voltage rated. However I am not sure if you have a microwave convection oven or an oven with microwave as two different units.

If the nameplate shows 208/120 or 240/120 then for 30 amps you need a NEMA 14-30P and a 14-30R.

If the unit is single voltage rated then for 208 or 240 you will need a 6-30P and 6-30R.

Go here for reference.......

I am also assuming your 10/3 is a cable that includes a ground wire so you would have 2 hots, a neutral and a ground (4 wires total)

dcd22 10-03-2007 08:25 AM

Here are the spec's, it looks to me like a single power source. It is a Jenn Air JMW8530DAB

Power Source:Max. Amp Load:30 Total Connected Load:6.6 kW @ 240V / 5.7 kW @ 208V Electric Supply:120/240 VAC , 120/208 VAC Power Source:Electric Ratings:CSA approval,UL listed

I thought he would hardwire to, but when we ran the line from the panel, it is cut short in the wall box.

The unit is not here yet and I am just trying to get all the part's needed to finish. I am sure it is easier if I see the unit and take it from there WITH my electrician there, but am trying to stay ahead of the game.

Yes, it is 10/3 with a ground.

HouseHelper 10-03-2007 09:45 AM

These units are typically hard wired. If the electrician has a box in place, then he will connect the "whip" that will be attached to the new oven to that box for a hard wired connection.

dcd22 10-03-2007 09:56 AM

Ah, I see. So make the connection in the box. Got ya.

Stubbie 10-03-2007 10:19 AM

As househelper said these units are almost always hardwired as they come already equipped with an appliance pigtail (whip). Most of what I said is probably going to be irrrelevant. I was under the impression that you already had the unit ready for installation and it was a cord and plug approved appliance. At any rate next time you do something like this leave plenty if extra cable at the connection point before you install the box . Then when you get the unit you will be able to tell where the best location for the connection will be, then install the junction box. The instructions may state if you can cord and plug the oven. Your problem may be where the junction box is located. My suggestion is that when you get the unit and if you come up to short to reach where you put the junction box with the factory pigtail, then run a new 10/3 that is long enough. This will make for a much better installation and your pocket book won't be damaged too much. I wouldn't try to add on a piece to the 10/3 circuit. It would be acceptable to cord and plug if the manufacturer approves. I've never cord and plugged one of these though and I've never stuck a plug on the end of the factory pigtail that comes with the appliance.....hardwire it. Since you have a family member that is an electrician he should know what is required.

BTW.... Your appliance is dual voltage so you have the right cable. My guess would be that your supply is likely to be 120/240 if this is a single family home.


dcd22 10-03-2007 10:25 AM

Perfect, thanks guys. I will definately run a long enough line from the panel if not long anough to make the single connection from the appliance. I have enough 10/3 left over to do so, so no issue with $$. Hell, this kitchen is WAY over anyway, whats another $100 in wire!!!!!

Again, I am sure it will get done right, just wanted to get an idea prior to. In the end, it looks as if I do not need to buy anything!!!

Stubbie 10-03-2007 10:30 AM

Is your junction box going to be flush mounted inside the wall cavity or surface mounted outside the wall?

dcd22 10-03-2007 11:31 AM

Right now, the wire is brought up from the crawl, up the wall cavity and it is coiled up in a single gang box in the wall (plastic box).

Andy in ATL 10-03-2007 02:37 PM

The single gang box isn't going to be big enough. I'm not sure about box fill( no code book handy) but experience says that with the whip provided by the manufacturer what you (your electrician family member probably already has) will need is a 1900 box (roughly 4"X4"X1.5" steel with 1/2" knockouts), one 1/2" romex connecter for the 10/3 , one 1/2" metal flex connector for the whip, four red wirenuts, one green ground screw to bond the box and a cover for the above 1900 box. It's a long list but really it's not... it sounds complicated but really it's very easy.:) The most important thing in any wiring project like this is to GET THE WIRE NUTS AS TIGHT AS POSSIBLE. Loose wire nuts start fires. Tight wire nuts will last a lifetime. Good luck and post when completed.

Big Bill 10-04-2007 05:34 PM

Sorry to interrupt ...


Originally Posted by dcd22 (Post 65844)
..... I do not want to hardwire it, I want to add a cors, plug and receptical (unless there is reason not to).

Last year we had our kitchen remodeled. The contractor wanted the electric stove to have an outlet and plug, not hardwired.
At the time I didn't know what difference it would make, so I asked the electrician.
He stayed neutral (no pun intended) on the subject and would wire it either way.
Result was he hooked up the outlet and installed the wire and plug.
When we went to push the stove into the opening, the stove contacted the plug, so there was a few inches between the stove and the wall, and the stove stuck out from the cabinets. It didn't look good.

The electrician was kind enough to come back and remove the outlet/plug, and hardwire it. The stove then went flush against the wall, and looks good now.


dcd22 10-08-2007 07:53 AM

we went with a receptical and cord in the single gang box, it fit fine. It is a 3 wire application (ground and neutral are tied together). He knew what all this meant and now I have a receptical and cord waiting for the unit.

We did take come measurment's to make sure it would fit OK, but we will see.

HouseHelper 10-08-2007 12:10 PM


Originally Posted by dcd22 (Post 66864)
we went with a receptical and cord in the single gang box, it fit fine. It is a 3 wire application (ground and neutral are tied together). He knew what all this meant and now I have a receptical and cord waiting for the unit.

We did take come measurment's to make sure it would fit OK, but we will see.

If this is a new installation (new wire pull from the panel) it is a code violation to have the neutral and ground tied together. Your electrician should know this. You should undo this "3 wire application" and install the proper 4 wire receptacle with a separate neutral and ground.

Stubbie 10-08-2007 12:32 PM

Hmmmmm....I guess I'm having trouble understanding what you did?

You say you ran a new 10/3 g to the oven/micro location. This is a four wire branch circuit.

Now you have that 10/3 g to a 3 wire receptacle and tied the neutral and ground together in that receptacle????

If so this is all wrong!!

You now have 2 paths that neutral current is going to travel back to the panel. That ground wire in the 10/3 is not to have neutral current on it!!

As Househelper has said.... big time code violation.

You did the absolute right thing running a new 10/3 g.... but now you have it all wrong at the connection point for the oven.

You need to correct this.... this is a very hazardous installation as you have done it.

Ask your electrician friend/family member to explain ....maybe we are just not communicating correctly.

Do not install the oven/micro with a 4 wire 120/240 volt branch circuit to a 3 prong receptacle and cord!!

Wait till you purchase the unit. If it comes with a 4 wire factory pigtail to hard wire... then hard wire the unit. This is the preferred method. If the unit installation instructions say you can cord and plug (they may so no) then change to a 4 wire cord and plug and 4 wire receptacle as househelper has said.


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