CH metermain

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sparky_magoo

Senior Member
Location
Reno
I recently installed a CH 200A residential metermain. The socket was on the lower left side. The entire top section was for the bus and breakers leaving plenty of make up room. Nice. The can is 15 inches wide. I had to pull all of the nails out of a shear wall to move a stud a half inch. Major PITA.

Our POCO wants the meter at 5"4" above grade. This puts the top breaker over 6"6". I couldn't find the code reference to breaker height. Would some one help me out with the code section.

Thanks.
 

iwire

Moderator
Staff member
Location
Massachusetts
sparky_magoo said:
This puts the top breaker over 6"6". I couldn't find the code reference to breaker height. Would some one help me out with the code section.

Thanks.

404.8(A)

6' - 7" to the top of the handle
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
sparky_magoo said:
The can is 15 inches wide. I had to pull all of the nails out of a shear wall to move a stud a half inch. Major PITA.

I would have cut a 1/2" slice from the stud just for the needed height. I've done it plenty of times. How?

With a reciprocating saw and a strong short blade (i.e., the Milwaukee Ax), make a 1/2"-deep cut sideways top and bottom, and then either split the piece out with a hammer and chisel or cut it carefully with the recip saw, depending on how straight the wood grain is.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
One small example you've probably seen is where they use real wood for sheathing at the corners of a typical house, and the black stuff over the rest of the walls. Older pre-plywood construction often had diagonal bracing at the corners.

The real shear wall is used where the construction methods are weak laterally, such as large walls of mostly glass. Strong sideways wind loads and earthquakes can cause such a house to collapse.

Shear walls are often exterior walls, but can also be interior walls. If you ever see a house of all-glass walls with a solid plane of an inside wall, that's the shear wall. Imagine a pre-hung door frame with and without the door in place.

Here's pics of a wall with and without shear-resisting panels:

Shear2.jpg
Shear1.jpg


Notice how the first wall can easily be "racked" by sideways force, while the panels stiffen the second; drywall does the same thing to stud walls. Shear panels have specific minimum nail-screw pattern requirements.
 
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George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
Is there a set rule on how much you can cut out of a shear wall? For example, can a full 42-space load center be cut into a shear wall without compromising the wall?

I've done that before, and got away with it, but never was really sure if I should have.

Around here, every now and then (more so in some cities than others), we'll come across a house with an interior shear wall. The framers are not always kind enough to put the OSB on the outside of a second-floor bedroom wall. It makes it real interesting when that wall is the wall/ceiling of the Great Room below. ;)
 

hillbilly

Senior Member
Thanks LarryFine for the definition. I know now what a "shear wall" is.
I've always heard the carpenters around here call it "bracing", corner bracing" or corner sheathing"
steve
 

bphgravity

Senior Member
Location
Florida
Not to change the subject, but if this is the same CH meter-main I see installed regularly, be sure to carefuly read the instructions on WHERE to make the service entrance connections.

The factor installed lugs must be removed from the bottom bars and relocated to the bars at top of the meter for overhead service drops. It's common to find the overhead conductors from the mast looped around the meter socket to the bottom lugs. Those can only be used for underground installations up through a riser.
 
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