Need some electrical code answers

[Lee Schierer]

My sister asked me to take down her existing range hood so she can do some cabinet painting before the new range hood is delivered and installed on Friday. When I removed the range hood I found that the wire coming through the wall apparently wasn't long enough so whoever put in the range hood added more wire with some wire nuts. This junction was not in a box or protected in any way.

Here's are the questions:
A. Does code allow a junction box to be in the wall behind the range hood where it would protect the junction, but be behind the range hood. Would this constitute an inaccessible junction box.

Or

B. Should the junction box be installed in the cabinet above where the range hood would be mounted, where it would be accessible without removing the range hood. The wires would go through the bottom of the cabinet to where they can be connected to the new range hood.

Pulling new wire to that point isn't an option since we don't know from what point in the circuit the wire is connected.

[Frank Pratt]

Canadian electrician here, but our codes are mostly harmonized at this point. A JB behind the range hood is fine. After all, to access the box behind a light fixture, the fixture needs to be removed. If you do put a JB in the cupboard & run new cable through it down to the hood, it will need to be armored cable because it is subject to mechanical damage.

[Charlie Velasquez]

Assuming. 12ga or 14ga romex (nm-b).
The wire nuts need to be boxed. If you can access it from the attic that would suffice.
However easiest might be an approved and listed in-line splice that is rated to be hidden in walls without a box.
This is one brand, Tyco, carried by most big box hardware stores.

[Lee Schierer]

If you do put a JB in the cupboard & run new cable through it down to the hood, it will need to be armored cable because it is subject to mechanical damage.

If If I create an opening in the bottom of the cabinet and securely attach the JB to the inside bottom of the cabinet over that opening. The supply wire comes out of the wall and go into the bottom of the JB from the space that is covered up by the range hood and are clamped with twin screw cable clamps through the bottom of the box. Once the range hood is installed the wire from the JB to the connection on the range hood is all confined in the space between the bottom of the cabinet and the top of the range hood, is armored cable required? There would be no access from the cabinet to the wires unless you removed the cover of the JB and no access to the wires unless the range hood is taken down.

[Frank Pratt]

Here's how I'd do it. I'd put a JB (or the splice Charlie showed) behind the hood fan and splice in a long tail, about 5' or 6'. Having that length will allow you to make the connection to the hood while it's laying upside down on the countertop. Then as the hood is raise in place, just stuff the excess cable into the wall. It's so much easier than doing the connection with the hood already in place. I have installed well over a 1000 hood fans & that is the system that worked for me.

The device that Charlie referred to is not legal in Canada and honestly, even if it was I wouldn't use it in a truly concealed setting because it's still a splice that can go wrong. Using it behind a range hood would be good though because it can still be accessed.

[Jim Becker]

Most current range hoods, including the very nice Hauslane I just installed, require a normal 120v outlet and are not hard wired. Installing them is no different than an over-range microwave. (which I'm thankful is now gone!) So I suspect the solution is going to be to put an outlet in place to do the job. If she has selected her new hood, you should be able to get the specifications/installation instructions, even if she has not already ordered/purchased it. And if the wire is just coming out of the wall, you'd obviously need to do an old work box to install an outlet)

[Frank Pratt]

There are increasingly hoods that just plug in, especially high end ones, but most under cabinet mount ones are still hard wired, excepting the infamous over the range microwave/exhaust units. I've installed several dozen of those in the day. But I have never, ever met anyone with anything nice to say about them after having used them a while. They look good, but are just a bunch of turds.

[Lee Schierer]

Thank you one and all. The JB is installed in the cabinet. There were too many obstacles to put a box in the wall. Plaster over lathe for one. The original wire goes up into the bottom of the cabinet directly into the JB with a clamp. The MC cable comes out of the bottom of the JB through the bottom of the cabinet to where the installer can connect the range hood. I have no information on the range hood except it is supposed to arrive tomorrow. If an outlet is needed there will be more work to do.

[andrew whicker]

How thick is a plaster over lathe wall? Those remodeling outlets might go deep enough..

[Lee Schierer]

How thick is a plaster over lathe wall? Those remodeling outlets might go deep enough..

It wasn't a problem of thickness of the wall. It was trying to locate the JB in a place where it would be covered by the range hood, miss the longer cabinet to the left, miss the stud and nailer in the wall and be below the bottom of the cabinet above with the limited length of the existing wire.

[andrew whicker]

sounds painful.

[Tom Bender]

If your new hood is not ducted to the outdoors it is just a light and a noise maker.

[Lee Schierer]

If your new hood is not ducted to the outdoors it is just a light and a noise maker.

Not my house, not my choice.

[Bill Dufour]

How is a plug in range hood allowed by NEC? I thought plug in were temporary. You cannot have a permeant extension cord setup can you. I suppose the bath vent fans are allowed since the plug is inside the junction box and not exposed. Also being in the ceiling it is not exposed to traffic wear and tear.
Bill D

[Kev Williams]

If your new hood is not ducted to the outdoors it is just a light and a noise maker.
While non-ducted range hoods won't keep the steam vapor from cooking from recirculating back into the kitchen, their screens WILL capture the grease and oils within the steam...

[Frank Pratt]

While non-ducted range hoods won't keep the steam vapor from cooking from recirculating back into the kitchen, their screens WILL capture the grease and oils within the steam...

Only a fraction will be captured.

[Jim Becker]

How is a plug in range hood allowed by NEC? I thought plug in were temporary. You cannot have a permeant extension cord setup can you. I suppose the bath vent fans are allowed since the plug is inside the junction box and not exposed. Also being in the ceiling it is not exposed to traffic wear and tear.
Bill D

It's no different than an over-range microwave/fan combination, Bill. Those all require a plug-in receptacle in the cabinet above, too. Range hoods that are designed as direct replacements come the same way...the Hauslane unit I just installed (which is excellent) was specified that way. There's no "extension cord"...the outlet is required to be within a certain area. I did need to take the cabinet down to create the pathways for the venting, but otherwise, nothing changed with the switch from the (undesirable) over range microwave/fan (unvented) to the new hood (vented) electrically.

[Bill Dufour]

How thick is a plaster over lathe wall? Those remodeling outlets might go deep enough..
My old house, 1949, was 1/2" button board with 1/2" hard coat plaster on top of that. I would say plaster and lath would be the same or thicker total.
The old work boxes almost work with the button board walls. I got good at mounting them next to a stud with screws from the inside of the box. I used. a Aro pancake drill to drill pilot holes and a pnumatic ratchet to drive hex head roofing screws.
Bill D

[Lee DeRaud]

You guys realize OP has already finished this, right?

[Maurice Mcmurry]

The vent vs vent free hood debate is interesting. Wood lath and plaster is 3/4 inch thick. I have seen it as thin as 1/2" and as thick as 1"