Any electricians out there? Take a look at this pics please

[will e]

My mom had an oven installed as part of a kitchen remodel. Combo Oven and Microwave. 208 volt. Here are the wires from the oven:



The instructions say to connect the white/green to 'white'. The red to red and the black to black. But this is what the electrician ran:



There are two black wires and the open copper wire (ground wire).

The oven was installed and functioning (for about a week) but had to be removed to fix a cabinet panel, nothing to do with the electricity. It's not currently connected.

This doesn't look right to me. I have done a bit of electrical work, mostly 110V. But when I wired my oven I used 4 wire (red, white, black and ground).

I don't see how he can hook this up without using the ground wire as the 'common' as well. Am I missing something?

[dodgerammit]

Ground and "common" or "neutral" will go to the ground bar inside the breaker.

If the wiring between oven and breaker box was existing, then not really his fault, especially if house is an older house that started with the 3 wire 220 stuff before 4 wire 220 came around.

If he ran new wiring from oven to breaker, then he skimped. That connection should be 4 wire all the way to the box.

Either way, it looks like whomever ran the wire ran general 12 gauge 110 stuff in place of 3 insulated strands. FWIW, 12-2 is rated to 600v.

[bigun]

First off unless you have three phase in the house it isn't 208. For simplicity connect the white and the ground to the bare copper wire. Then it doesn't matter black or red which wire you connect to the black wire or the white that has been phased black.
Your real problem is # 12 wire is only good for 20 amps and is small to carry the load in fact if you read the manufactures label it states it needs to be a # 8. First thing you need to do is check the panel and make sure some dumb ass hasn't put a 40 amp breaker on the #12, next thing if you love your mom is to get the circuit rerun in the proper size wire, they make a insert to fill the gap and cover the exposed wood so you don't set her cabinet on fire if there is a short

[bigun]

Looked at it again I bet your cabinet guy said don't worry about an electrician I have done this lots of times, If so get ready to have him pay through nose to get it fixed right because he just tried to cause your mom to loose her house to a fire The bitch of it all is when it is investigated and has been determined to have been an electrical fire my trade gets the blame Did he also paint the tan wire nut red?
The idiot couldn't even cut the box out in the right place, let me guess a local handy man

[bigun]

Don't any of you watch Holmes, dude is a bit full of himself but he tell truth about letting people do work on your house they aren't qualified to do

[bigun]

Oh by the way the manufactures sheet shows how to hook to a three wire circuit, but I am glad you did not see that.

[bigun]

And if the cabinet guy questions you I have 20 plus years in the trade and own my own company.

[will e]

I am confused.

There are a total of three wires in the same romax coming from the breaker box. I believe it is all new wire. I can probably pull off the front panel and know for sure. There are two sheathed wires and the copper unsheathed wire. It's okay to use that unsheathed copper wire as the common?

It was a licensed electrician who did the work.

[will e]

Here is the electrical requirement sheet:

[dodgerammit]

I am confused.

There are a total of three wires in the same romax coming from the breaker box. I believe it is all new wire. I can probably pull off the front panel and know for sure. There are two sheathed wires and the copper unsheathed wire. It's okay to use that unsheathed copper wire as the common?

It was a licensed electrician who did the work.

If all new wiring and he was licensed, can you have the codes dept check it out? If so, they'll be giving him a call.

[SJTD]

The destructions say it all. Use the 3 wire cable where codes allow but they're showing that as red/black/white with no ground but you have two conductors and a ground which as you said is being used for the neutral.

Is it legal? Idunno, prolly not. I don't think it's especially dangerous. The ground wire would usually be 14 gauge but it's probably only carrying current for the lights and clock, etc and now you don't have a dedicated ground.

He colored the neutral black which is ok if he did the same at the other end. Red/black doesn't really matter if it's a dedicated 240 circuit for the oven. Look at the drop from the power lines. There's no red and black.

Whether 12 gauge is ok depends on the model as specified at the top of the second column of the second sheet you show. The first page say does say 8 gauge. Maybe that sheet indicates it's the bigger oven.

I hate Romex.

Is there access to run another cable?

[bigun]

What is the model number

[bigun]

Smallest 6.1 KW would require a 25 amp circuit so it would have to be a #10 and breakered at 30 amps
Now if it is a 4.2 KW yes it could be run in 12 and on a 20 amp breaker, but the manufactures sheet says use a number 8

[bigun]

I am confused.

There are a total of three wires in the same romax coming from the breaker box. I believe it is all new wire. I can probably pull off the front panel and know for sure. There are two sheathed wires and the copper unsheathed wire. It's okay to use that unsheathed copper wire as the common?

It was a licensed electrician who did the work.

Yes it is the way we did in the old days but with today's computer controlled stuff they require a neutral, plus the ground goes to the frame to protect, while the neutral carries the unbalanced load which you really don't want on your ground.
How old is the house?

[will e]

House was built mid 90's.

model number: woc54ec0hw03

It's a pretty short run from the fuse box. Maybe 25 feet including going up and down the walls.

[cpfeifffer]

Bigun is right. Sounds like your electrician was being lazy. I’d have it re-run with 3 insulated conductors with a bare ground based on the manufacturer recommended wire sizing. Last thing you want is that wire overheating in the wall. Just think “ammeter bypass” on a FSJ.

The separate neutral is a code requirement. Can’t find it right now.


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[bigun]

House was built mid 90's.

model number: woc54ec0hw03

It's a pretty short run from the fuse box. Maybe 25 feet including going up and down the walls.

The reason I asked age of the house is to make sure it didn't have aluminum wiring and this guy had just tied on to it with copper.
Your model says it need 7.5 KVW or 31 amps on 240 volts which means it would have to be run in a #8 and breakered at 40 amps.
All this information is available to the electrician on the manufactures label on the top right side, not to mention on the top left side it sates clearly to use a #8. I can't remeber the section dealing with there should be no gaps between the box and the device plate, but I am sure I can find it

[SJTD]

Yep, even setting the shortcuts with the two conductor cable aside, there's no way that's safe. Even if he ran if off a 20 amp breaker the wiring might be protected but the breaker would be continually blowing. Until someone else came along and said "there's you problem, that's supposed to be a 40 amp".

You don't mention the breaker tripping so that seems to indicate that it is a 40.

Did that guy run the cable or was the old oven running off that? If so was it smaller? Or was it gas and that circuit only powered the electrickery?

[will e]

Thanks guys. I will head over there in a couple of days and check out a few things. I will confirm the breaker rating. I will also pull the cover to see if the wires being used are his or original. If they tied into the previous oven/stove outlet it should be uncovered behind the cabinets right? You are not supposed to cover an electrical outlet.

I really appreciate the input.

[tgreese]

Bigun is right. Sounds like your electrician was being lazy. I’d have it re-run with 3 insulated conductors with a bare ground based on the manufacturer recommended wire sizing. Last thing you want is that wire overheating in the wall. Just think “ammeter bypass” on a FSJ.

The separate neutral is a code requirement. Can’t find it right now.


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You need the separate neutral if the oven uses 120 VAC to power the front panel, controls, etc. Single phase 240 VAC comes down from the pole with a center tap, dividing it into +120VAC above neutral and -120VAC below neutral. The neutral is tied to earth at the breaker panel. This is really earth or ground, going via a heavy wire directly to ground rods or where your copper water pipes enter the building. The only difference between the upper 120VAC and lower 120VAC, from the 120VAC appliances perspective, is the phase.

240VAC does not "need" the neutral (pole transformer center tap), but it does need the safety ground. As described above, the safety ground and neutral are connected back at the breaker panel. At the point of use, these wires can be at different potentials, since current returns to the panel via the neutral and not via the safety ground, except in a fault. The resistance of the returning neutral cause a potential difference between the neutral and safety ground. Normally that's really small, but you can measure it.

You could use the safety ground for clocks, controls etc. but I'd guess that would play havoc with more modern safety enhancements like GFCI and AFCI etc. Thus code likely prohibits it. Bigun may know more about this.

Bigun has you covered. I'm not an electrical professional, but I understand electricity some and have investigated these topic to satisfy my curiosity. I would expect 8ga 4-conductor copper wire back to a 40A 240VAC breaker based on the conversation here and my over-educated inexperienced POV.