Section 336-10. Exposed Work ? General.

[joe tedesco]

Subject:

Electric water heater installed in 1993 or earlier.

Article 336 - 1993 Edition of the NEC:

B. Installation

336-10. Exposed Work ? General.

In exposed work, except as provided in Sections 300-11(a), 336-12, and 336-13, the cable shall be installed as specified in (a) and (b) below.

(a) To Follow Surface.

The cable shall closely follow the surface of the building finish or of running boards.

Question: Does this section allow NM cable whips or short lengths to be used for the supply to a 120 gallon or less electric water heater?


Present NEC:

334.15 Exposed Work

(A) To Follow Surface. Cable shall closely follow the surface of the building finish or of running boards.

334.30 (B) Unsupported Cables. Nonmetallic-sheathed cable shall be permitted to be unsupported where the cable:

(1) Is fished between access points through concealed spaces in finished buildings or structures and supporting is impracticable.

(2) Is not more than 1.4 m (4 1/ 2 ft) from the last point of cable support to the point of connection to a luminaire (lighting fixture) or other piece of electrical equipment and the cable and point of connection are within an accessible ceiling.

 

[joe tedesco]

Keep in mind that NM is the old style TW 60c.

You say it is okHow about this rule?


The cable shall closely follow the surface of the building finish or of running boards

 

[George Stolz]

Question: Does this section allow NM cable whips or short lengths to be used for the supply to a 120 gallon or less electric water heater?

334.15 (A) To Follow Surface. Cable shall closely follow the surface of the building finish or of running boards.

Wherever NM is not protected by virtue of running along the building finish or along running boards, we are afforded an alternative solution:

334.15(B) Protection from Physical Damage. Cable shall be protected from physical damage where necessary by rigid metal conduit, intermediate metal conduit, electrical metallic tubing, Schedule 80 PVC rigid nonmetallic conduit, or other approved means.

 

[tonyi]

I always use MC or AC.

However, if you ran a runner down right next to the heater, and had the last staple/tie within 12" of the heater's little connection box, why not?

[yea, I know hardly anyone does it that way, but I believe there exist SOME way to do it strictly legally even if nobody does it that way in the field]

 

[infinity]

The way I read it ( 2005 NEC) you can have the last 4.5' of cable unsupported if it feeds a luminaire or piece of equipment. This portion would be permitted to not follow the building finish providing it went to the hot water heater. The 1993 reference provided seems to prohibit this.

 

[macmikeman]

I personally don't like to see it done. What I do like to see is a 4s metal box installed on the surface, and flexible conduit with 90 deg conductors down to the heater itself. That said, both could be considered to be subject to physical damage, depending on what might possibly happen or not possibly happen to damage the cable or flex conduit.

 

[LarryFine]

What I do like to see is a 4s metal box installed on the surface, and flexible conduit with 90 deg conductors down to the heater itself.

Would not at least one strap be required on the wall below the box?

 

[cpal]

Joe where are you going with this, and how have you been??

Charlie

 

[don_resqcapt19]

Trevor,
The section that you are talking about only applies above an accessible ceiling.

(B) Unsupported Cables Nonmetallic-sheathed cable shall be permitted to be unsupported where the cable: ...
(2) Is not more than 1.4 m (4 1/ 2 ft) from the last point of cable support to the point of connection to a luminaire (lighting fixture) or other piece of electrical equipment and the cable and point of connection are within an accessible ceiling.

Don

 

[infinity]

Trevor,
The section that you are talking about only applies above an accessible ceiling.

The section that you are talking about only applies above an accessible ceiling.
Don

Oppps, you're right Don. I simply looked at what was in the OP instead of double checking the book. Sorry for the mistake.

 

[macmikeman]

Would not at least one strap be required on the wall below the box?

You bet Larry, thanks for pointing out the ommision.

 

[joe tedesco]

Doing real fine.

Doing real fine.

Joe where are you going with this, and how have you been??

Charlie

Charlie: Doing real fine. Just wanted to see what people see when they read the rule. My point was "follow the surface of the building or of running boards"

The issue came up in another HI forum, and the old Type NM was used, so I added the rule that covered the question.

Which Charlie are you?

 

[allenwayne]

If in a readily accesable area like a garage then cover the NM I like to use carflex over armored flex.But if in an attic like an airhandler then feed it without worry.