Hi Peter, I have installed a lot of RMC. You may have also. It is my opinion that a well secured run of this conduit, installed in this manner, could take the hit you describe and still protect the enclosed conductors.
--- You wrote: (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. --- end of quote --- --- You wrote: 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 --- end of quote --- How about switching to Rigid Nonmetallic Conduit just above grade and going underground, around the chimney, and on to the location of the disconnect or entry. No comment on the reasonableness of the requirement. Dick Dick Ratico Solarwind Electric Bradford, VT _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
