Kent,

I looked at the photo of that expansion coupling and initially thought, "That'll
work". But....  if the conduit was RMC OR IMC all the joints would have been
THREADED into couplings, and even if by mistake they were not wrench tight, they
would not have pulled apart. Even if strapped too tightly, the roof blocks would
probably pull over first. With EMT, contraction pulled apart the weakest link in
the chain, a loose slip fitting.

Thanks William.

Dick
Solarwind Electric

--- You wrote:
2) The expansion joint fabricated from adapters for different conduit 
systems probably works fine and may not have been a contributing factor 
to this fire, but it is prominently visible in the report.  
--- end of quote ---

