[RE-wrenches] Chimneys Rigid vs EMT

[SOLARPRO at aol.com]

Peter:
 
Newport Beach, CA.  They backed away from the AC run in rigid  however.  It 
was either rigid OR a remote DC disco, operable from the  ground at the main 
service entrance, that would cut off all power to runs at the  array.  No 
chimney issues as of today, at 11:24 AM PST, March 6,  2009.
 
People should get their systems soon before it will be impossible to get a  
permit (or afford the design changes).
 
All the inverter manufacturers should be working on micro inverters and  give 
Enphase a run for their money.
But a micro-inverter would not help in Pasadena, apparently.
 
Patrick A. Redgate
AMECO Solar, Inc.
7623 Somerset,  Blvd.
Paramount, CA 90723
562-633-4400

_www.amecosolar.com_ (http://www.amecosolar.com/) 


In a message dated 3/6/2009 10:56:15 A.M. Pacific Standard Time,  
peter.parrish at calsolareng.com writes:

We have  an interesting situation in the enclave of Pasadena, CA. 

(1) The  Pasadena Building and Safety Department is requiring the use of
rigid  conduit (only) on any DC and AC runs for grid-tied PV systems.  They
specifically prohibit EMT, LFNC and LFMC. This requirement applies to  any DC
or AC runs on the roof, and it applies to any DC or AC runs on  exterior
walls.

They do not require the use of rigid conduit on A/C  equipment, lighting or
any other piece of equipment requiring  exterior-mounted conduit conveying
electrical power.

(2) They also  disallow a rigid conduit run anywhere on the exterior surface
of a chimney.  Where a conduit run on an exterior wall encounters a chimney,
they require  that the conduit run follow the line where the chimney meets
the wall/roof.  This means up the wall, along the roof and back down  the
wall.

Although I think (1) is overkill, I will comply this once  and engage the AHJ
before the next job we have in this town; I have graver  reservations about
(2). I have lived over 50 years in California and I have  seen the results
severe earthquakes can have on residential chimneys. If  the chimney goes,
the first place it happens is on the unsupported portion  above the roof. The
next place the chimney fails is the higher portion,  attached to the building
frame. I think I can remember just one case where  a chimney failed within 3
feet of the foundation, and in that case most of  the rest of the structure
failed. Consequently if a chimney fails, there  will be hundreds of pounds of
brick raining down on the rigid conduit where  it runs along the chimney roof
interface.

I would argue that the  safest place for a rigid conduit run would be around
the chimney in the  crawl space (if any) underneath the house, attached to
floor joists. If  that option is not available I would argue for a run around
(and anchored  to) the exterior chimney at about 2-3 feet above grade.

Is item (2)  essentially a B&S issue not addressed by the Fire Department? 

Has  anyone encountered these sorts of requirements  elsewhere?

Comments?

- Peter

Peter T. Parrish,  President
California Solar Engineering, Inc.
820 Cynthia Ave., Los  Angeles, CA 90065
Ph 323-258-8883, Mobile 323-839-6108, Fax  323-258-8885
CA Lic. 854779, NABCEP Cert.  031806-26
peter.parrish at calsolareng.com  


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