Drawing Wires

Acad R13

I often have to draw cables between circuit breakers that are offset. The breaker heights are fixed, so getting the correct bend in the wire is often difficult.

I have been drawing separate intersecting plines and filleting them a random radius until they look right, but this is very time consuming and the end result is hit or miss.

Any help, as always, is so appreciated.

breaker wire.dwg

have you tried the "arc" function while drawing the polylines?

This is an interesting challenge. With ortho snap on I would draw a vertical line from the 3 posts of the two breakers. I would then make a copy of the three lines from the breaker that are closest together and rotate them 90° and move them so they are centered between the two breakers. Using chamfer I would get a layout something like this.

Using PEDIT convert each wire to a single pline then use PEDIT S to convert the pline to a pline-spline (not to be confused with a NURBS spline).

If you like the result great. If not, select the spline to see its CVs (control vertices).

The first two CVs of the spline define its starting point and slope. We want to keep the wire's slope vertical at the start and end. To ensure this we will only move the first and third CV in a vertical direction (ortho mode is still active) so just click on the 2nd or 3rd CV and move it up/down until you like the results. For example,

The final results.

You can of course copy and stretch the wire as needed for other breakers.

There is a little known command added in 2012 called BLEND. Draw a short line from the breakers, start the blend command, pick both lines. The spline can be converted to a pline by clicking on it once, right click, Spline, pick convert to pline, use a value like 6 when asked. Join the three objects as a pline, add width. Rinse and repeat for the other two.

Thinking out side the square its something that could be automated pick terminals top, pick terminals bottom, pick bottom level, pick top level between terminals and end up with the 3 lines using some simple intersection pts, the middle line as in this case as its 3 terminals would be based on the middle of the top & bottom y values, for 4 it would be a third. Then use the excellent ideas about splines etc as posted.

Just to be sure, are you using AutoCAD R13 (circa 1994), or AutoCAD 2013?

Isn't the purpose of the drawing to show how two terminals are supposed to be wired?

Do you provide curve data for the bends in the wires such as the delta, radius, length of curve, etc.?

Is there a note on the drawing to the electrician specifically addressing the way the wires should be installed?

How often do you field check that the bend in the wire, as installed, matches that of your drawing?

I never liked using splines or poly lines for my drawings because most of the wire I run is not in conduit. For electrical drawings you will have a one line that shows what connections go where and how different systems are connected. It's up to the electrician to run the conduit to where it needs to go and that's not on the drawings most of the time. The last time I used curved lines to represent the connections between my fire alarm devices the electricians ran the wire exactly as it was drawn on the prints which added a ton of time to the job because they were running wire into and out of rooms that had no devices but the prints showed the wire running into those rooms. I now only use straight lines and make the connections following a logical real world run between devices. Granted I'm not on site to know if my wire runs can go in the direction I draw them but I depend on the abstract thinking of the person running the wire to figure it out. I get a lot of phone calls to say the least on these jobs but that's better than trying to explain 10 more hours on the job than you figured in.