Sunday, November 11, 2012

Underground Electrical Conduit

We bought 2 inch PVC electrical conduit, matching what Austin Energy does with the power line.  Byrd says that telephone and cable conduits should be at least a foot away from the electrical lines, so we positioned a separate run up the wall for the cable and telephone lines.

From the wall, we put in a 90-degree connector to change from vertical to horizontal, and then after a slight distance a 45-degree to head to the back of the yard.  A 10 foot section takes us under the bridge (and where the pathway will be) and into the main pit.

That's were we run into problems.  We need to turn the conduit to head towards the green City transformer box.  Both the cable and telephone lines originate neat the green transformer box.   But the angle we need to turn is probably something like 16 degrees.  Standard connections come only in 90 and 45 degrees.  In the picture below, you can see that both a 90 and 45 degree turn would be way too much.

But we had seen that there are two flavors of 90-degree connectors.  One is fairly small; the other takes about 2 feet to slowly turn 90 degrees.  Byrd says that is meant for fiber optics, which can't turn quickly.

We noticed that for the larger, slow turning 90-degree connector, that if we cut it at any given point, the pipe is almost straight at that point, at least for a couple of inches -- long enough that a connector won't notice that it is slightly curving.  So we can find the point where the tangent to the curve is pointing in the direction we want, and cut it there.  Then connect the 10-foot straight piece and we have a good connector for our specific angle.  The slight curvature in the connectors might mean it is not a perfect fit, but since this is for a conduit, not for pressurized water, that should not matter.

This extends the conduit all the way to the area near the electrical transformer box.

Now all we have to do is find one end or the other of the cable and telephone lines and run them thru the conduit.

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