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I have a log home and would like to correct the kitchen counter-top receptacles. I have discovered the following problems that necessitate rewiring the entire kitchen (new cabinets/countertops were installed recently by previous owner).

  1. No GFCI.
  2. Wire splits somewhere inaccessible (probably behind counter -- requiring me to GFCI each receptacle.)
  3. Only one circuit
  4. Not enough boxes to meet the 2ft/4ft rule.
  5. Wire is run through the cabinets -- visible (not behind the cabinets)

I've allocated two circuits and plan to put the fridge and three receptacles on one and the gas range and four on the other. I will be adding two boxes. I plan to router a channel for the wires in the solid log wall above the counter tops and then install the backsplash over the wire. I am curious if hardiboard and tile (between 3/4 to 1 inch total of material) is sufficient protection for the wiring. Does code require some kind of metal protection or min distance from the surface? ...in the event someone tries to drill a hole in the backsplash? I want to make the groove depth as small as possible as one wall is an exterior load-carrying wall.

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Could you post photos? –  Bryce Feb 4 at 0:54
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3 Answers 3

up vote 2 down vote accepted

Protecting the Cable

National Electrical Code 2014

Article 300 Wiring Methods

I. General Requirements

300.4 Protection Against Physical Damage.

(F) Cables and Raceways Installed in Shallow Grooves. Cable- or raceway-type wiring methods installed in a groove, to be covered by wallboard, siding, paneling, carpeting, or similar finish, shall be protected by 1.6 mm (1/16 in.) thick steel plate, sleeve, or equivalent or by not less than 32-mm (11/4-in.) free space for the full length of the groove in which the cable or raceway is installed.

Exception No. 1: Steel plates, sleeves, or the equivalent shall not be required to protect rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, or electrical metallic tubing.

So you have a couple options.

Free Space

Run the groove deep enough, so that there's 1 1/4" of free space in front of the cable.

Steel Protection

Protect the cable using a 1/16" steel plate, or sleeve. Or install the cable in rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, or electrical metallic tubing.


Dividing the Circuits

National Electrical Code 2014

Article 210 Branch Circuits

I. General Provisions

210.11 Branch Circuits Required.

(C) Dwelling Units.

(1) Small-Appliance Branch Circuits. In addition to the number of branch circuits required by other parts of this section, two or more 20-ampere small-appliance branch circuits shall be provided for all receptacle outlets specified by 210.52(B).

III. Required Outlets

210.52 Dwelling Unit Receptacle Outlets.

(B) Small Appliances.

(1) Receptacle Outlets Served. In the kitchen, pantry, breakfast room, dining room, or similar area of a dwelling unit, the two or more 20-ampere small-appliance branch circuits required by 210.11(C)(1) shall serve all wall and floor receptacle outlets covered by 210.52(A), all countertop outlets covered by 210.52(C), and receptacle outlets for refrigeration equipment.

Exception No. 2: The receptacle outlet for refrigeration equipment shall be permitted to be supplied from an individual branch circuit rated 15 amperes or greater.

(2) No Other Outlets. The two or more small-appliance branch circuits specified in 210.52(B)(1) shall have no other outlets.

Exception No. 2: Receptacles installed to provide power for supplemental equipment and lighting on gas-fired ranges, ovens, or counter-mounted cooking units.

So as far as your plan for dividing up the circuits, you're spot on.

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I hadn't considered running 12/3 to all the receptacles as @Edwin suggests. A strict interpretation of the NEC "two or more ... circuits shall be provided for all receptacle outlets" might suggest this? So that at least one socket on every receptacle continues to work if one circuit is tripped? Seems nice, but is it common practice? –  Paul Feb 4 at 14:41
    
@Paul What it means when it says "two or more ... circuits shall be provided for all receptacle outlets", is that you must have at least two 20 ampere circuits to supply the receptacles in a kitchen, not that each duplex receptacle must be supplied by two circuits. In my experience, it's not common to power duplex receptacles with two circuits. –  Tester101 Feb 4 at 14:52
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Your issue is covered in the National Electric Code, for installations in the USA:

NEC 300.4 Cables and raceways shall be protected from damage. Where installed through bored holes in wood framing members, the holes shall be bored so that the edge of the hole is not less than 1¼ inch from the nearest edge of the wood member, or shall be protected by a 1/16 inch steel plate.

So basically you need 1¼ of solid wood material (not counting the wallboard/wall covering) to buffer access to the wire, or a metal plate.

But in your case I'd I recommend using armored cable (formerly known as 'bx'). Or emt (conduit). Then you've got no worries.

Frequent practice is to have the fridge on it's own circuit, and the dishwasher (if you've got one) is required to be on its own.

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I'd like to add that you only need one 12/3 armored cable to feed outlets. You can wire the top outlet to red, bottom to black if you remove the fin on the hot side of the outlet. The route just needs to be big enough to to accommodate the one cable. –  Edwin Feb 4 at 3:52
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I don't think armored cable meets the protection requirements. 320.17 Through or Parallel to Framing Members. Type AC cable shall be protected in accordance with 300.4(A), (C), and (D) where installed through or parallel to framing members. Also, you'll probably want to look at 300.4(F) (shallow Grooves) not 300.4(A)(1) (Bored Holes). –  Tester101 Feb 4 at 12:31
    
Once it gets down to this level, a better forum for highly technical distinctions is the NEC code forum at forums.mikeholt.com . The other option is to call the local building inspector, since they are the ultimate judge. I'll add emt as an option above. –  Bryce Feb 4 at 18:59
    
@Bryce Mike Holt's forum is for professional Electricians, and students/apprentices. They don't typically like folks outside the trade posting. However, it's a good resource if you're just there to read the threads. –  Tester101 Feb 5 at 0:22
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You should use either flexible metallic conduit or 1/16 inch steel plates to protect the wiring behind the backsplash if you can't put the cable at least 1 1/4 inches from either edge of the stud. (I agree with Bryce). Since you said you're going to be notching/grooving the path, you will need to use the flexible metal conduit for continuous protection and you might also be interested in this area of the residential code:

R602.6 Drilling and notching-studs.

Drilling and notching of studs shall be in accordance with the following:

1. Notching. Any stud in an exterior wall or bearing partition may be cut or notched to a depth not exceeding 25 percent of its width. Studs in nonbearing partitions may be notched to a depth not to exceed 40 percent of a single stud width.

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The OP said that he was working on a solid log wall. No studs. –  Edwin Feb 4 at 6:47
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