1. ## Electrical cable routing

Last edited by RobertSmith; 12-20-2007 at 01:44 PM.

2. ## Re: Electrical cable routing

Yes, it is a problem. They can be pinched or damaged.

3. ## Re: Electrical cable routing

Originally Posted by RobertSmith
electrical cables are routed between the two walkboards?
Walkboards? As in "in the attic"?

If so, those need to be routed elsewhere and/or protected from physical damage (so you don't damage them while walking on that floor surface. That floor surface (walkboards) leads to/from where?

4. ## Re: Electrical cable routing

Use "(H) Bends. No bend shall have a radius of less than five
times the cable diameter.", from 551.47 Wiring Methods.
I know it says through studs but it is a good rule.

5. ## Re: Electrical cable routing

Originally Posted by Mike Parks
Use "(H) Bends. No bend shall have a radius of less than five times the cable diameter.", from 551.47 Wiring Methods.
I know it says through studs but it is a good rule.
Er ... Mike, Did you look to see where 551 applies?

ARTICLE 551 Recreational Vehicles and Recreational Vehicle Parks

Now, if you want wire bending limitations, you have to go to 110.3(B) and then to the manufacturers.

There's more to the attached than just the table but the file size was too large to upload, and the table gives all that is really needed anyway. On the left column is the thickness of the insulation - almost every insulation seen in residential use will be the thinner thickness; the columns to the right are the overall diameter of the cable/conductor (including insulation), and almost every conductor/cable in residential use will be in the farthest left column - 1" and smaller; thus, the minimum wire bending RADIUS is 4 times the DIAMETER of the conductor/cable. The problem I find with most electricians is that they use 4 times the conductor diameter as the 'diameter' of the bend, not the 'radius' of the bend - big difference.

Example 1: 2/0 is about 1/2" in diameter, its minimum bending radius is 4 times that, or 2", meaning a 4" diameter circle, if bent in a 'U' shape.

Example 2: NM cable - when bending in the flatways direction, use that cable thickness; when bending in the sideways direction, use that much larger cable width. Makes a HUGE difference in the minimum bending radius.

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