Eric in North TX wrote:
Without any idea what the intended use for the feeder is, it's
impossible to

give advise, however if its a clean straight shot, three 3\0 conductors will
fit. Just make sure you don't try pulling it with the nylon strand


The intended use is to power a workshop with a 4 post lift, air
compressor, welding equipment, and a wood shop (mostly 220v). It is a
one person shop generally, so it would be unusual to have more than one
load at a time, though my so has welded while I sanded or lifted a car,
and with the present hopelessly inadequate feed it browned out the
entire shop.
I had every intention of using the nylon to pull the wire, glad you
mention that, what should be used? I have pulled cars with that stuff,
I thought it was bullet proof.


Eric
As someone has already suggested you will want an Equipment Grounding
Conductor (EGC) in that feeder unless it is supplied from a separate
service with it's own meter directly from the local power company. If
that feeder will share a service with any other building then you really
want an EGC in that feeder. The reason for the concern is that if a
neutral connection ever failed the current it carries would try to
return to the source via any other grounded conductive pathway. Those
can include telephone lines, cable jackets, intercom lines, security
wiring, metallic piping systems, and the local earth itself. Such stray
currents can cause electric shock, erratic behavior in pets, pour
production in dairy cattle, destruction of metallic systems, and under
some circumstances fire. The practice of running feeders without EGCs
will no longer be allowed under the next edition of the US National
Electric Code.

On a separate subject if the trench has not been fully back filled you
should take this opportunity to install a one inch low voltage raceway
so that you can run communications, alarm, and video wiring between the
two buildings at a later date.
--
Tom Horne

"This alternating Current stuff is just a fad. It is much too dangerous
for general use." Thomas Alva Edison