Subpanel location, mounting on the joist

Users who are viewing this thread

JWelectric

Electrical Contractor/Instructor
Messages
2,608
Reaction score
21
Points
38
Location
North Carolina
I wonder why it is a bad idea to bundle NM cable

romexbundling.jpg


There might be a good reason if one looks hard enough
 
Last edited by a moderator:

electrotuko

Member
Messages
58
Reaction score
0
Points
6
Location
Austin, TX
The reason very clearly seen from the picture: the bundle is tire-wrapped very tight, plus it runs through the insulation, not enough cooling, air circulation, wires even changed color from overheat. My is a bit different case, wires going through the non insulated/free air space, and was thinking to tire wrap them not completely, just create a loop and keep NM-B loose inside. But I got the point again, thanks for your comments.
Homeownerinburb, thanks for advising NM cable support. I am afraid that would not be so convenient way, it will cerate an obstacle in the crawl, kind of something hanging down from the ceiling, some one can hurt his head. Better would be more flat implementation, for example:

http://www.cyberguys.com/product-details/?productid=62778&rH=1645

I will nail/staple them individually to joists instead, next to each other, 2" spacing out or so.
How about 3/8" Metal flex, can I run them in a bundle, loosely bunched together and hung this under each joist?
 
Last edited:

JWelectric

Electrical Contractor/Instructor
Messages
2,608
Reaction score
21
Points
38
Location
North Carolina
either of the two devices with links driven to the side of the joist would work or even two cables under one staple.

Dig out the required working space and install the panel if that is what trips your trigger.
 

electrotuko

Member
Messages
58
Reaction score
0
Points
6
Location
Austin, TX
Exactly, that was the goal for having an elegant solution. Drill one hole in the floor to get to crawl space from the main panel. Run one 50' cable (easy to mount to each joist) through that hole to subpanel and from here easy split multiple NM-B's to all directions.
Looks like the subpanel still an option.
Few last things to clarify:
It is not required to have a concrete floor in the area subpanel mounted? It is a gravel in the crawl.
What is required minimum distance from the bottom/center of subpanel to the floor?
 

DonL

Jack of all trades Master of one
Messages
5,205
Reaction score
72
Points
48
Location
Houston, TX
"It is not required to have a concrete floor in the area subpanel mounted? "

I think that must be a California thing.

What part of Texas do you live in ?
 

DonL

Jack of all trades Master of one
Messages
5,205
Reaction score
72
Points
48
Location
Houston, TX
Them should be just fine.

Not sure why you could not use 4, Maybe JW can answer that.

I did not see any rating, or approval.

What forum says only 3 can be used ?

Your Flag looks a lot like ours.
 
Last edited:

JWelectric

Electrical Contractor/Instructor
Messages
2,608
Reaction score
21
Points
38
Location
North Carolina
It is not required to have a concrete floor in the area subpanel mounted?
Concrete is not a code requirement.

It is a gravel in the crawl.
That makes things rough on the knees.
What is required minimum distance from the bottom/center of subpanel to the floor?
Unless this is a mobile home there is no requirement on the minimum mounting height. The highest breaker can be no more than 6 feet 7 inches above grade but you could sit the panel on the ground if you so desired. In order to have the required working space the top of the panel must be below the floor joist.

All of this is in the code section you referenced in your first post.
 
Messages
594
Reaction score
0
Points
16
Location
Los Angeles, CA USA
I wonder why it is a bad idea to bundle NM cable



There might be a good reason if one looks hard enough

Wow. Now that is some inductive heating going on there!

I wonder how many current carrying conductors are in there?

That might have been legitimately derated to about four amps per conductor from the size of that bundle.
 
Last edited by a moderator:

DonL

Jack of all trades Master of one
Messages
5,205
Reaction score
72
Points
48
Location
Houston, TX
You don't like a Mediterranean climate where you can go about in shorts and a t-shirt more than 11 months per year?


Mediterranean climate ? Are you kidding.

I froze my butt off on the coast there with the wind blowing off of the water.

It is a nice place to visit, but I would not want to live there.


What are you going to do when they run out of drinkable water ?
 
Messages
594
Reaction score
0
Points
16
Location
Los Angeles, CA USA
Exactly, that was the goal for having an elegant solution. Drill one hole in the floor to get to crawl space from the main panel. Run one 50' cable (easy to mount to each joist) through that hole to subpanel and from here easy split multiple NM-B's to all directions.
Looks like the subpanel still an option.
Few last things to clarify:
It is not required to have a concrete floor in the area subpanel mounted? It is a gravel in the crawl.
What is required minimum distance from the bottom/center of subpanel to the floor?

When you get to the end of your questions, and have only those specific to your region, you might want to go ask your local authority.

Speaking of what CA is asking of us here now: when running NM under the floor in a crawl space, they want for us to install nailers such that nothing can be hung on the cable as it goes from one joist to the next.

As I understand it, you need to secure the cable every 4' or there abouts. Not to each joist.
 

electrotuko

Member
Messages
58
Reaction score
0
Points
6
Location
Austin, TX
jwelectric, you mentioned:

you could sit the panel on the ground if you so desired. In order to have the required working space the top of the panel must be below the floor joist.

But earlier you pointed out to 110.26(A)(1)(2)&(3) and noted:
and have a head room of at least 6 ½ feet.

Just to clarify, can the subpanel be mounted 4 feet above the ground? How about the headroom of 6 1/2' you mentioned.
It would be mounted on your suggested 3/4" ply board, making in the same high of my I eyes when sitting on the floor.
 

JWelectric

Electrical Contractor/Instructor
Messages
2,608
Reaction score
21
Points
38
Location
North Carolina
jwelectric, you mentioned:
you could sit the panel on the ground if you so desired
But earlier you pointed out to 110.26(A)(1)(2)&(3) and noted:
Just to clarify, can the subpanel be mounted 4 feet above the ground? How about the headroom of 6 1/2' you mentioned.
It would be mounted on your suggested 3/4" ply board, making in the same high of my I eyes when sitting on the floor

Look closely at 110.26 and you will see that the working space, or the space in which one would be standing while working in the panel is required to be 30 inches wide, 36 inches deep and 78 inches high. This working space is the area in which one will be standing while working in the panel.

The panel itself can be mounted anywhere between zero inches and 79 inches to the center of the grip of the highest breaker.

In a dwelling unit I have never in 47 years pulled out a ruler to measure the panel. I mount the panel at a good working height for me.

If your heart desires to mount the panel so you can sit on a nail keg to work in the panel that is your choice. You can mount it as high as your heart desires as long as the highest breaker in the panel is no higher than 6’ 7” above finish grade.

You said you have 6 feet of head room under the house so you will need to dig a hole that is at least 30 inches by 36 inches so you can achieve a head room of 6.5 feet. Mount the panel at any height your heart desires as long as it is no higher than the bottom of the floor joist.

If your heart desires to install hooks so you can hang by your feet to work on this panel then by all means sit it on the ground although in my personal opinion this would be a lot of work for nothing and then you might have a family of Armadillos trying to bite your nose while you are working on that panel.

By the way have you ever had armadillo stew? Does it really taste just like chicken?
 

electrotuko

Member
Messages
58
Reaction score
0
Points
6
Location
Austin, TX
The work is in a finishing up stage.
Just curious if this is acceptable.
The main panel is installed between studs on the outside wall. Now having added wires coming out to crawl.
There are approx. 10 wires NM-B going down and 15 up from then panel. I was thinking of putting insulation in the area surrounding panel, between studs, were are the wires. Now worrying if this is OK to cover that whole area with the fiber glass insulation, since many wires over there, can get preheated. Wires not bundled, going in a parallel pattern. Is this Ok to insulation as per NEC?
 

DonL

Jack of all trades Master of one
Messages
5,205
Reaction score
72
Points
48
Location
Houston, TX
The work is in a finishing up stage.
Just curious if this is acceptable.
The main panel is installed between studs on the outside wall. Now having added wires coming out to crawl.
There are approx. 10 wires NM-B going down and 15 up from then panel. I was thinking of putting insulation in the area surrounding panel, between studs, were are the wires. Now worrying if this is OK to cover that whole area with the fiber glass insulation, since many wires over there, can get preheated. Wires not bundled, going in a parallel pattern. Is this Ok to insulation as per NEC?


Can you take pictures ?


Good Luck on your project.
 

electrotuko

Member
Messages
58
Reaction score
0
Points
6
Location
Austin, TX
I can take few pictures, in a few least questionable areas, to void some criticism...:)

Just to reiterate my worry:
Can I cover the area (insulate wall) with fiberglass R-16 below and above the panel where many NM-B wires going up/down from the panel. Afraid to have temp rise or so. Is NEC OK with this?
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks