) said...

Is it possible/code to pull three #10 and three #8 wires thru a 3/4"
steel conduit?

It depends on what the insulation is! It is the cross sectional area
that matters, as you are not supposed to exceed 40% of the conduit's
area.

If all these wires have T90 Nylon insulation, then their cross section
area is only 31.8% of the conduit's. If they are TW75, then they are 39.6%,
so they would also fit. If they are RWU75 EP, then they are 63.8% of the
conduit's fill.

I have a "conduit calculator" available for free at http://daxack.ca that
comes with cross-section data for a number of different types of wire.

--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
- Napoleon
-------------------------------------------------------------------------
NOTE: if replying by email, remove "remove." and ".invalid"