Cable Staples?


  #1  
Old 02-03-05, 08:10 AM
brianosaur
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Thumbs down Cable Staples?

What's the purpose of cable staples?

I took the drywall down in a few rooms and am running new wires for a new light and ceiling fan. I see the original electrician put staples near the boxes and at the top of the studs. There were also a few in the ceiling joists when it ran down the length of one.

I know that they need to be used, but is it to keep the wire away from the drywall so no nails or screws can be driven into the wire?

Or is it to prevent pulling the wire too tight?

I know not to set cable staples too deep into the wire, but are there any more tips on placing and setting staples?

Thanks
 
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Old 02-03-05, 08:20 AM
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NEC and Staples

Dear Brian,

The use of staples in the installation serve many purposes. But the most important one as a Electrician I can import is that the NEC requires them in Art 336 and it governs what a electrician can do with regards to the installation which is also covered in Art 300.

The code states that NM and NMC be supported at intervals not exceeding 4 1/2 feet and within 12in from any box, cabinet or fitting per the NEC code section 336-18 ( 1999 NEC)

Now beyond that as a electrician we understand that these cables need to be supported in order for them to NOT run the risk of something pulling on them and causing wires to be pulled from or exposed from the outlet to which the wire(cable) is run.

Also not to mention a neater job is a happier client for the most part. Our firm has always been a stickler for neat installs not because we can see it....but because our clients CAN'T see it and what you can't see should not have to worry you.
 
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Old 02-04-05, 09:41 AM
T
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Fasten in finished walls?

Call me a worrier, but I don't want to do something wrong that may last another 40 years and affect the safety of young lives. I am planning to re-wire my finished house and know that the NEC says if I fish wire through my finished walls I do not have to fasten it. Is there any concern that the wires might be pulled loose if not stapled in walls that are already finished?

I realize that there is always the chance something might happen, but is the thinking behind the code that an unfinished house has a greater chance of wiring being pulled loose than a finished one?
 
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Old 02-04-05, 09:51 AM
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Of course there is concern. But the concern is not great enough that the code requires you to open the walls to put in the staples.

The only way to keep your house as safe as it can be is to update it to the latest codes every year. This of course would require you to tear the whole house down every year and rebuilt it. Safety and codes always involve compromises.
 
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Old 02-04-05, 06:58 PM
W
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I was told this by a licensed electrician (which I am not) so I have no clue as to it's validity.
He said the original intent of the staples was to create an intentional short circuit in the wire during a house fire (as the insulation melted) so that the breakers would trip and electricity would not pose a hazard to individuals trying to extinguish the fire (presumably with water).

Comments or ridicule?
 
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Old 02-04-05, 07:06 PM
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I tend to think he was pulling your leg. The first thing they do is cut power at a fire. I have heard some stories about how they do it if the POCO isn't extremely punctual.
 
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Old 02-04-05, 07:18 PM
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Since the Firemen generally get there way ahead of the POCO, anything that tripped a breaker would probably be an advantage.
Not to go off on a tangent, but since I am with a POCO, I'm curious as to what these methods might be. The local firemen here generally wait on us, which admittedly doesn't do the house any good.
 
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Old 02-04-05, 07:35 PM
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The existence of plastic staples does not support the intentional short theory.
 
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Old 02-04-05, 07:36 PM
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I once heard a story invloving an axe. Then again, they were probably pulling my leg.
Most just pull the meter. I believe in my area they are allowed if the POCO is a few minutes out. We know what 5 minutes can do to a house on fire.
 
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Old 02-04-05, 07:39 PM
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Hey, I just noticed my edit button is back!

I thought of that John, but the plastic would melt of the staples as quick as the cable sheathing.
My thought was staples were around much longer than NM cable. I can't see a staple helping to short out early BX,can you?
 
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Old 02-07-05, 06:34 AM
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Lol...considering a staple is attached to wood and wood is not much of a conductor..lol...I guess the guy is thinking hey the jacket will melt and the insulation will melt and the system will ground out....lol...

Well news for you...if it gets that HOT.....no need to have it short out the house is TOAST anyway so the theory is only that...theory my friend...lol

Kinda neat way to look at staples however...lol....I can see it now in the 2008 NEC...Staples an effective means of grounding a circuit..lol
 
 

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