Wiring through kitchen plinth?

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  #1  
Old 01-20-13, 04:32 PM
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Wiring through kitchen plinth?

Yeth, a plinth.

I'd appreciate your help with the following project. Thanks a lot in advance!

I am moving my gas range and its 32-amp downdraft motor, fed by #6 aluminum cable, from a corner to the center of the kitchen. This means an L-shaped extension, about 9 feet per leg.

For the first leg of the L, can I feed the cable through the plinth of the new base cabinets, or do I need to fish it through new holes in joists?What kind of conduit is required? I suspect it will be RMC, because it's > 6 ft.

The second leg is between two floor joists. What are the requirements for this run? Conduit & connectors.... What special requirements does aluminum SE on a branch circuit impose ?
 
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  #2  
Old 01-20-13, 04:44 PM
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The conduit would only be required if the cable would be subject to damage.

Your fan must be huge to call for a 32 amp circuit.

A picture might help us to understand your situation.
 
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Old 01-20-13, 04:49 PM
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Not to mention #6 aluminum. Plan on replacing it all from the panel with copper. 32 amps!!! My welder doesn't pull that much. Where is it mounted? Certainly not in conjuction with a stove, as the food would never get warm and the flame would extinguish with the vortex.
 
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Old 01-20-13, 06:09 PM
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Oops. I should have said that this blower motor is fed through a junction box it once shared with an ELECTRIC range, Thermador, 120/240 3-wire alumnimum cable that drew 35 amps on a 50 amp breaker. I got rid of the electric range and replaced it with a gas cooktop. So now the loads are 1 amp for the motor that drives the periscope-style downdraft up and down, maybe an amp for the sparker, and 4.3 amps for the new internal motor for the blower. (I got it through eBay from a Pittsburgh appliance store. It had been ordered by Lynn Swann and returned. Says Swann on the box. Any offers?)

So they had originally put in this damn SE aluminum cable for a much bigger load. It's a major pain to run another outside conduit to the subpanel, so I thought I would use this honking cable for the 5 amp load; have my split bolts and anti-oxidant and rubber tape ready. I don't want to think about a CU/AL junction.

There's a wiring diagram at the last page of 14-Wiring-CV2136-01 parts for Thermador TMH45P-01 - AppliancePartsPros.com and I can try to put in a clearer one if it's helpful.

So grateful for your help.
 
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Old 01-20-13, 06:17 PM
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Any chance you can just put a subpanel where the cable is now and run a 15 amp copper circuit to the new location?
 
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Old 01-20-13, 06:56 PM
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The old cable might be 240 only. In addition to the splice, you might have wiring changes and definitely a breaker swap.

Polaris connectors are easier than split bolts.
 
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Old 01-20-13, 07:00 PM
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I thought of that Ray, but I don't have the phyical 3' clearances required by the code. :>(
 
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Old 01-21-13, 03:17 PM
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Rewiring Thermador exhaust fan

Mod Note: Merged thread.

Hi. When I bought my house it had a Thermador electric range top and snorkel-type downdraft with an external blower fan. I got rid of the electric range and replaced it with gas. I am now moving the gas cooker and downdraft to an island in the center of the kitchen, and am putting in an internal blower motor (1-phase / 120 volt 4.3 amps)

It's still served by the old branch 35-amp SE-R 6 AWG aluminum cable (2-wire plus ground on a 50 amp breaker). Either I extend that wire (which I'd prefer to avoid) or I have only enough conduit space to bring in dedicated 12- amp THHN CU cables to serve the new blower motor and the gas range (1 amp) and downdraft on a 20 amp circuit.

Can you guys tell me, from the attached wiring diagram, whether I can replace the 2-phase 240/120 service with single phase 120? Remember, I lost the 35-amp electric burner load. If I stay with the aluminum SE-R, can I run 1-phase 120 through it with a new breaker?

Thermador support is worse than useless. I cannot put in a sub-subpanel either. Thanks a lot. Wiring diagram attached
 

Last edited by ray2047; 01-21-13 at 03:40 PM.
  #9  
Old 01-21-13, 03:50 PM
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Debeze, I have merged your new thread to your old one because it is basically an extension of your first thread.

Can you guys tell me, from the attached wiring diagram, whether I can replace the 2-phase 240/120 service with single phase 120?
Both are single phase. You would replace the two pole breaker with a single pole 20a breaker. If you do not have a insulated white wire in the SE cable it can't be reused because by code #6 and smaller the neutral must be [i]Factory[i] white not a recolored black or red. There is also the whole problem of connecting copper to aluminum. Since the #6 isn't going to fit a 20 amp breaker it will need to be pigtailed to a #12 copper at the panel in addition to the extension in the plinth. A lot simpler/better/safer to run new cable.

No diagram attached to your post.
 
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Old 01-21-13, 10:02 PM
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THermador solution?

Thanks, Ray. You are everywhere. I think I might have solved it. Please tell me if the following makes sense. Better than a photo, i have attached a link to the wiring diagram, which i have annotated.

Here is my proposed plan of action. What do you think?

1. Change breaker to 20-amp single phase
2. Cap off SE-R cable in subpanel and in kitchen
3. Run #12 THHN via conduit from new breaker to the Thermador.
4. Splice new incoming black THHN to L1 and L2 in the diagram. (Note, all 2-phase loads (i.e.. burners) are gone.
5. New 20 amp 1-phase circuit would supply power to the 4.3 amp 120 V blower motor through wires 88 and 16 (See CV2536 blower motor in upper right hand corner of diagram)
6. Same circuit would drive the gear motor to raise/lower downdraft snorkel through wire 27 (top center.)
7. Use neutral (wire 1 upper LH corner) as return
8. Run a ground from the Thermador/island back to the RMC box.

An electrician recently installed 3/4" RMC outside my house. This means I will be pulling thirteen 12 AWG stranded THHN wires through it--the other requisite kitchen circuits and a ground for safety's sake. That's legal. (16 is the NEC max). Do you suppose I can tug hard enough? Serious question, never having done it.

THanks again for your help!

Here's the link to the wiring diagram. It's fairly legible if you zoom in.

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  #11  
Old 01-22-13, 04:26 AM
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Note: all residential wiring is "single phase". You are just dropping from 240 volt double breaker to a 120 volt single breaker.

I doubt very seriously you will get 13 ea 12 gauge THHN conductors in a 3/4" conduit. If you have to "tug", it's too tight.

Is this a dis-integrated blower from a blower/range unit? Meaning it doesn't go with the current range top, but you salvaged it and are installing it in conjunction with another top?
 
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Old 01-22-13, 05:06 AM
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Any more then nine conductors require de-rating. Grounds don't count and you only need one ground per conduit or if continuous metallic the conduit can serve as ground though it isn't considered best practice. There was certainly no need for RMC unless it it is some local code. I suggest you install a second PVC conduit for some of the wires.

You seem to be making this way over complicated. Just run a 20 amp #12 circuit for the gas cooktop and exhaust.
 
  #13  
Old 01-22-13, 09:34 AM
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Hi, Chandler. The answer is to your question is yes. However, it was designed specifically for this unit. Thermador made two types: one for positioning outside the house, and oen that could easily be integrated with the downdraft in the cabinet carcase. They provide printed instructions for attaching either to the downdraft, so it's really an apples and apples thing. In this instance, I am swapping out an external one for an unused internal one.

Regarding the wire, I have never pulled through conduit before. Since the NEC allows 16 such conductors, it would seem to me it would be physically doable. Just wondering....
 

Last edited by debeze; 01-22-13 at 09:37 AM. Reason: unclear grammar
  #14  
Old 01-22-13, 05:10 PM
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But reading further will show, as Ray mentioned that they must be derated after 9, meaning your 12 gauge wires now become 10 gauge wires. It will be too simple to run another conduit with 12 gauge wires for your application alone and leave the other Rigid alone. How many wires are there in the conduit presently??
 
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Old 01-22-13, 05:45 PM
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Back in the day, two of us added a 19th conductor into a 3/4" conduit that already had 18 wires in it. Don't ask. Getting the fish tape through was harder than pulling the wire.

Lube - lots of it - is essential. Stranded wire is a big plus. Daisy-chaining the head really helps too.

However, given de-rating, you won't be able to use those #12 AWG wires for 20A circuits - only for 15A circuits. It's time to add a second conduit.

What loads do you need to feed? Maybe you don't need that many wires. Are you figuring on multiwire branch circuits, so that three wires give you two circuits?
 
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