Getting close to finalizing relocation of panel board. Using 1 1/4" emt from disconnect to board-both indoors. Planned on using compression couplings, but have also seen the set screw type in both steel and cast material.

Q-Any reason for the different material other then maybe manufacturing processes and/or costs?

Q-Any real world preference, reasons, application, between the set screw or compression? -- I am pulling a separate eqpt. Ground between the disconnect & board.

Compact conductors-THese are referred in Table C.1(A) in the NEC and a definition given, but I have never seen these mentioned as being used.

Q-Are service entrance conductors normally of the non-compact type?

Q-Is the compact more related to specific applications?

Compression is intended for rain tight installations, I have seen them used for others, but waste of money and labor. We normally use set screw for indoor work. Use them if you like.

"Compact" conductors are aluminum conductors.Each strand is made so that when laid to the others the cross sectional area is maximized to eliminate air space and increase surface contact with the other strands, and reduce resistance.

No where am I aware of is this explained in the code, just one of those things those in the trade know.

For additional info see;http://www.cable.alcan.com/alcancable/en-US/Products/United+States/Stabiloy+Building+Wire+Products/STABILOY+Type+XHHW-2.htm

Thanks tk, the link was helpful. Was trying to determine if my existing SEC was compact or not...