How to show break in lines in tikz?

Question

Im not sure what the term used for what I want so I will explain it. I want a double long drawn "S" to show that the line in my figure is actually longer than is shown- implying that there is a missing segment in between the two "S"s in the picture. If you look at the output of the diagram below it might make more sense. Looking at the dimensions in the picture, it is obvious that the lines are not drawn to scale, hence I need the lines to contain a break of the form I described above.

EDIT:

Here is a rough example of what I mean, showing the break. I guess the slanted line could also work but the "S" is ideal but should be uniformly thinner than shown in this picture.

\documentclass[tikz]{standalone}
\begin{document}
\begin{tikzpicture}
\draw (4,0.2) -- (8,0.2);
\draw (4,1.8) -- (8,1.8);
\draw[semithick,to-to] (4,2.5) -- +(16,0) node[fill=white,font=\footnotesize] at +(7.75,0) {100 m};          
\draw[semithick,to-to] (4,-1) -- +(8,0) node[fill=white,font=\footnotesize] at +(4.0,0) {10 m};
\end{tikzpicture}
\end{document}

Answer 1

We can use the pic environment from PGF 3.0 to define any pattern and just use it as a node wherever we want. Here is an example of a line break of the last pattern as per the OP:

\documentclass[tikz,border=2mm]{standalone}
\tikzset{ext/.pic={
\path [fill=white] (-0.2,0)to[bend left](0,0.1)to[bend right](0.2,0.2)to(0.2,0)to[bend left](0,-0.1)to[bend right](-0.2,-0.2)--cycle;
\draw (-0.2,0)to[bend left](0,0.1)to[bend right](0.2,0.2) (0.2,0)to[bend left](0,-0.1)to[bend right](-0.2,-0.2);
}}
\begin{document}
\begin{tikzpicture}
\path [draw] (0,0)--pic {ext}(0,2);
\path [draw] (1,1)--pic [rotate=90]{ext}(3,1);
\end{tikzpicture}
\end{document}

This gives the following output:

Answer 2

\documentclass[tikz,border=5mm]{standalone}
\usepackage{amssymb}
\begin{document}
\begin{tikzpicture}
\draw (4,0.2) -- node[fill=white,rotate=90,inner sep=-1.25pt,outer sep=0,anchor=center]{$\approx$} (8,0.2);
\draw (4,1.8) -- node[fill=white,rotate=0,inner sep=-2.5pt,outer sep=0]{//} (8,1.8);

\end{tikzpicture}
\end{document}