- Location
- Massachusetts
Re: NM-B cables through studs
[ March 23, 2005, 08:54 PM: Message edited by: iwire ]
Well?
[ March 23, 2005, 08:54 PM: Message edited by: iwire ]
- Status
Re: NM-B cables through studs
Larry: i jumped when I should have zigged or zagged. I apologize for the application of my graphic to you, and i should have read your post slower. Mine was aimed at a whole procession of posters going back a couple of years. I am dragging the paper now. Who's going to come up with the graphic?
But i still think that for the most part, it is a moot code item, whether wood or steel studs, because for the requirement to have any impact, the wire has to be derated below it's normal usage. I do not have a 2005 to argue with, but I do not even know who is on the 2005. jurisdictions in California might go that way in 2006, but we are still waiting to adopt the 2002.
As a matter of reasoning, I do not see the difference of fire stopping a hole that has 3 14-2's, and the wires seem loose, and a hole with 2 12-2's that is tight.
I think that there ought to be a rule about craming wires tight in holes, but this rule doesn't work. I agree with sandsnow's point.
In looking at old nm wiring, overtightened connectors, overdriven staples, squeezed wires are where I have seen damage. I have seen bundled nm without problems over and over and over.
I think this rule is a poor attempt to fix an actual problem. I think it may be that the only way to actually get at this problem (wires pulled so tight in a hole that they can't be removed, or even moved ) is to write a an actual item about this. Remember we allow more than one 12-3 in connectors without derating, so it is not so easy. Giving power to the workmanship code might work, but then we will be giving discretion to inspectors, some who have no clue but the words them selves, no experience to compare.
But i do not see this current code as a fix for that hole so crammed, you could bet that the insulation is off some of the wires. That is where I have seen the evidence of fires starting, not 4 14-2's flopping loose in a 3/4" hole.
sorry for the animosity i created, still think the graphic is applicable to unaware mistake.
paul
Larry: i jumped when I should have zigged or zagged. I apologize for the application of my graphic to you, and i should have read your post slower. Mine was aimed at a whole procession of posters going back a couple of years. I am dragging the paper now. Who's going to come up with the graphic?
But i still think that for the most part, it is a moot code item, whether wood or steel studs, because for the requirement to have any impact, the wire has to be derated below it's normal usage. I do not have a 2005 to argue with, but I do not even know who is on the 2005. jurisdictions in California might go that way in 2006, but we are still waiting to adopt the 2002.
As a matter of reasoning, I do not see the difference of fire stopping a hole that has 3 14-2's, and the wires seem loose, and a hole with 2 12-2's that is tight.
I think that there ought to be a rule about craming wires tight in holes, but this rule doesn't work. I agree with sandsnow's point.
In looking at old nm wiring, overtightened connectors, overdriven staples, squeezed wires are where I have seen damage. I have seen bundled nm without problems over and over and over.
I think this rule is a poor attempt to fix an actual problem. I think it may be that the only way to actually get at this problem (wires pulled so tight in a hole that they can't be removed, or even moved ) is to write a an actual item about this. Remember we allow more than one 12-3 in connectors without derating, so it is not so easy. Giving power to the workmanship code might work, but then we will be giving discretion to inspectors, some who have no clue but the words them selves, no experience to compare.
But i do not see this current code as a fix for that hole so crammed, you could bet that the insulation is off some of the wires. That is where I have seen the evidence of fires starting, not 4 14-2's flopping loose in a 3/4" hole.
sorry for the animosity i created, still think the graphic is applicable to unaware mistake.
paul
jwelectric
Senior Member
- Location
- North Carolina
Re: NM-B cables through studs
Bless your heart Bob. When you are running your MC cables through rings you will be trying your best to keep them straight and neat, right?
Don?t forget to read the last sentence of exception 5 that goes like this, A 60 percent adjustment factor shall be applied where the current-carrying conductors in these cables that are stacked or bundled longer than 600 mm (24 in.) without maintaining spacing exceeds 20.
Should you decide to separate these cables between the rings then they wouldn?t be bundled. See how easy this gets.
When I am pulling NM through studs that is going to be covered with dry wall I will keep the cables separated between the studs. This is easy to do due to the studs being 14 ? inches apart.
This book is not hard to understand if we don?t try to make it hard. It is designed so that a person who has never had a license can understand it enough to be able to pass a test. If they can do that how hard can it be for those of us that have years of experience to understand? If it is it is because we make it that way.
Bless your heart Bob. When you are running your MC cables through rings you will be trying your best to keep them straight and neat, right?
Don?t forget to read the last sentence of exception 5 that goes like this, A 60 percent adjustment factor shall be applied where the current-carrying conductors in these cables that are stacked or bundled longer than 600 mm (24 in.) without maintaining spacing exceeds 20.
Should you decide to separate these cables between the rings then they wouldn?t be bundled. See how easy this gets.
When I am pulling NM through studs that is going to be covered with dry wall I will keep the cables separated between the studs. This is easy to do due to the studs being 14 ? inches apart.
This book is not hard to understand if we don?t try to make it hard. It is designed so that a person who has never had a license can understand it enough to be able to pass a test. If they can do that how hard can it be for those of us that have years of experience to understand? If it is it is because we make it that way.
jwelectric
Senior Member
- Location
- North Carolina
Re: NM-B cables through studs
Dillion , I agree that it refers to the table but as was pointed out to me before the table falls under the article according to code etiquette
Dillion , I agree that it refers to the table but as was pointed out to me before the table falls under the article according to code etiquette
- Location
- Massachusetts
Re: NM-B cables through studs
Bless your heart it is easy. so why are you having such a hard time with it?
What is the minimum distance between ties, holes or bridle rings before it becomes bundled?
Bless your heart it is easy. so why are you having such a hard time with it?
What is the minimum distance between ties, holes or bridle rings before it becomes bundled?
jwelectric
Senior Member
- Location
- North Carolina
Re: NM-B cables through studs
- Location
- Massachusetts
Re: NM-B cables through studs
Paul you keep bring up questions about the size of the hole. Where is that in the NEC
If I run a 6" RMC and install ten 14 AWGs in that 6" raceway they are subject to the same derating as ten 14 AWGs in a 3/4" raceway.
Paul the 60% derating is in exception 5 that I asked about.Originally posted by apauling:
Bob: i have the 2002 and it does not contain a 60% in the 310.15.2a (if i typed that right). And i never saw 12 wires in a 3/4 hole. have seen 5 14-2's though.
paul
Paul you keep bring up questions about the size of the hole. Where is that in the NEC
If I run a 6" RMC and install ten 14 AWGs in that 6" raceway they are subject to the same derating as ten 14 AWGs in a 3/4" raceway.
- Location
- Massachusetts
Re: NM-B cables through studs
JW that is a laughable explanation. :roll:
jwelectric
Senior Member
- Location
- North Carolina
Re: NM-B cables through studs
Thank you Bob for allowing me to cause you humor on such a beautiful night. It is a proven fact that when a person is laughing they are free of all stress and it is a lot cheaper than drugs. It joys my heart to know that I was able to give you a moment of stress free pleasure. Thank you.
None the less this is a true and code compliant statement.
[ March 23, 2005, 10:15 PM: Message edited by: jwelectric ]
Thank you Bob for allowing me to cause you humor on such a beautiful night. It is a proven fact that when a person is laughing they are free of all stress and it is a lot cheaper than drugs. It joys my heart to know that I was able to give you a moment of stress free pleasure. Thank you.
None the less this is a true and code compliant statement.
[ March 23, 2005, 10:15 PM: Message edited by: jwelectric ]
Re: NM-B cables through studs
Bob: I keep refering to that 3/4" hole because I actually read the first post where the question was about studs and nm, not MC and rings. AND nipples less than 24" are exempted from the derating, at least in the 2002 NEC, even if they are 6". AND you referred to the table, not the exception. AND what has that got to do with the topic of bored holes and runs of nm cable?
were back to the useless hoohaw of trying to fix a problem with the wrong code, as the code doesn't do much of anything for this problem.
paul
Bob: I keep refering to that 3/4" hole because I actually read the first post where the question was about studs and nm, not MC and rings. AND nipples less than 24" are exempted from the derating, at least in the 2002 NEC, even if they are 6". AND you referred to the table, not the exception. AND what has that got to do with the topic of bored holes and runs of nm cable?
were back to the useless hoohaw of trying to fix a problem with the wrong code, as the code doesn't do much of anything for this problem.
paul
Re: NM-B cables through studs
The largest hole that you can drill in a 2x4 is 1 inch because of the 1.25 inch nail clearance allowance plus you can oly drill away 1/3 of the wood.
Pulling just two 12/2 cables through the same hole is also a pain in a certain body part. I only did it whem I was using two 12/2 cables as a substitute for 12/4 or 14/4 back in the days when 12/4 or 14/4 was hard to get. Now that Home Depot stocks the stuff I would rather persuade my customer that the extra labor is not worth it.
The largest hole that you can drill in a 2x4 is 1 inch because of the 1.25 inch nail clearance allowance plus you can oly drill away 1/3 of the wood.
Pulling just two 12/2 cables through the same hole is also a pain in a certain body part. I only did it whem I was using two 12/2 cables as a substitute for 12/4 or 14/4 back in the days when 12/4 or 14/4 was hard to get. Now that Home Depot stocks the stuff I would rather persuade my customer that the extra labor is not worth it.
allenwayne
Senior Member
Re: NM-B cables through studs
Bundling.bundling,bundling it`s always bundling As long as the cable assys. are not stapled together for 24 in`s in a run it does not apply JMHO
Bundling.bundling,bundling it`s always bundling
As long as the cable assys. are not stapled together for 24 in`s in a run it does not apply JMHO 
sandsnow
Senior Member
- Location
- Southern California
Re: NM-B cables through studs
Paul
Apology accepted. Thanks
To me this is simple. When the cable go through the hole they are bundled (and for that inch and a half not suject to derating), BUT when they exit the hole and are still bundled with cables not exposed to air in the middle then derating needs to be addressed. To me that's what the code says. Call me wrong, but don't call me late for beer break
OliverParallel stapled NM? Please define. One on top of another or side by side or what?
mc5w
Building Code Rules (CAlif) for bored holes in sawn lumber
MAx hole for any 2x4 is 40 percent or 1 7/16
Max hole 60% (or 2 1/8)for non-bearing or any wall where each bored stud is doubled provided that not more than two successive studs are doubled.
holes no closer than 5/8 to edge.
Keeping your holes to 1/3 will ensure you're never called on it.
MC5w
I like your take that two cables is a pain in the same hole. We can talk about code rules (my original response) or what actually happens. The only time I see a lot of cables close together (that I would start to think about derating) would be near the panel or at a convenient point to go from 1st to 2nd floor.
Paul
Apology accepted. Thanks
To me this is simple. When the cable go through the hole they are bundled (and for that inch and a half not suject to derating), BUT when they exit the hole and are still bundled with cables not exposed to air in the middle then derating needs to be addressed. To me that's what the code says. Call me wrong, but don't call me late for beer break
OliverParallel stapled NM? Please define. One on top of another or side by side or what?
mc5w
Building Code Rules (CAlif) for bored holes in sawn lumber
MAx hole for any 2x4 is 40 percent or 1 7/16
Max hole 60% (or 2 1/8)for non-bearing or any wall where each bored stud is doubled provided that not more than two successive studs are doubled.
holes no closer than 5/8 to edge.
Keeping your holes to 1/3 will ensure you're never called on it.
MC5w
I like your take that two cables is a pain in the same hole. We can talk about code rules (my original response) or what actually happens. The only time I see a lot of cables close together (that I would start to think about derating) would be near the panel or at a convenient point to go from 1st to 2nd floor.
O
oliver100
Guest
Re: NM-B cables through studs
Re:Larry
My question was about thr minimum distnace between stapled side by side NM cables before derating is required.
Also, you are considering the 1 1/2" NM cable in a stud hole as bundled cables. If so, is it cumulative (for instance - in 16 holes you are going to reach the limits of 24" before derating) OR not?
Re:Larry
My question was about thr minimum distnace between stapled side by side NM cables before derating is required.
Also, you are considering the 1 1/2" NM cable in a stud hole as bundled cables. If so, is it cumulative (for instance - in 16 holes you are going to reach the limits of 24" before derating) OR not?
Re: NM-B cables through studs
Larry: thanks .
Back to the issue. The derating doesn't mean anything unless you have a tonof cables. You don't cumulatively add up the total where wires touch each other, and you can only get so many wires in a hole, and holes are spaced a bit apart, so it is uncommon to get to a derating % that actually means anything. You start the derating from the 90 degree column as all new nm is rated for 90 degrees. it takes more than a 70% rate to get below the actual usage for nm. Without looking it up it is just below double the amperage , so derating nm to 70% still leaves 14-2 above 15 amps, 12-2 aove 20 amps, and on up the line. It doesn't change anything until you start bundling cables near the panel and there are large numbers of home runs.
as this thread started about 3/4" holes in studs, it is near impossible to get to a level of derating that means much.
paul
Larry: thanks .
Back to the issue. The derating doesn't mean anything unless you have a tonof cables. You don't cumulatively add up the total where wires touch each other, and you can only get so many wires in a hole, and holes are spaced a bit apart, so it is uncommon to get to a derating % that actually means anything. You start the derating from the 90 degree column as all new nm is rated for 90 degrees. it takes more than a 70% rate to get below the actual usage for nm. Without looking it up it is just below double the amperage , so derating nm to 70% still leaves 14-2 above 15 amps, 12-2 aove 20 amps, and on up the line. It doesn't change anything until you start bundling cables near the panel and there are large numbers of home runs.
as this thread started about 3/4" holes in studs, it is near impossible to get to a level of derating that means much.
paul
mikeoconnor
Member
Re: NM-B cables through studs
Wow!I just signed up this week and I found my first code fight. I love a forum rumble. I'm going to start my own day long discussion at the job site twomorrow.........
Wow!I just signed up this week and I found my first code fight. I love a forum rumble. I'm going to start my own day long discussion at the job site twomorrow.........
sandsnow
Senior Member
- Location
- Southern California
Re: NM-B cables through studs
Across the top of joists: no derating issue with that for me
Up a stud:
Realistically won't happen because of staying 1 1/4 back from edge
Next topic
What is the 1 1/2" hole you speak of? Do you mean a 1 1/2" hole full of cables?
If you're talking about 16 sucessive studs then what is the cable like between the studs? See my last post as to my thoughts on the cable between studs.
Side by side;
Across the top of joists: no derating issue with that for me
Up a stud:
Realistically won't happen because of staying 1 1/4 back from edge
Next topic
What is the 1 1/2" hole you speak of? Do you mean a 1 1/2" hole full of cables?
If you're talking about 16 sucessive studs then what is the cable like between the studs? See my last post as to my thoughts on the cable between studs.
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