\documentclass[a4paper,ngerman,12pt]{article} 
\usepackage[T1]{fontenc} 
\usepackage[utf8]{inputenc} 
\usepackage{SIunits}
\usepackage{array}
\usepackage{rotating}
\usepackage{booktabs}
\usepackage{babel}
\setlength\parindent{0pt}% damit nicht eingerueckt wird

\makeatletter
% werden nicht alle benoetigt ...
\newcolumntype{f}{>{$}l<{$}}
\newcolumntype{n}{l}
\newcolumntype{N}{>{\scriptsize}l}
\newcolumntype{v}[1]{>{\raggedright\hspace{0pt}}p{#1}}
\newcolumntype{V}[1]{>{\scriptsize\raggedright\hspace{0pt}}p{#1}}
\newcolumntype{B}[1]{>{\boldmath\DC@{.}{,}{#1}}l<{\DC@end}}
\newcolumntype{d}[1]{>{\DC@{.}{,}{#1}}l<{\DC@end}}
\newcolumntype{R}[1]{%
  >{\begin{turn}{90}\begin{minipage}{#1}\scriptsize\raggedright\hspace{0pt}}l%
  <{\end{minipage}\end{turn}}}
\newcolumntype{x}{>{\scriptsize\raggedright\hspace{0pt}}X}
\makeatother

\begin{document} 

\begin{tabular}{@{}*{8}{n}@{}}\toprule% tab13.tex
\multicolumn{1}{@{}N}{Type} & \multicolumn{6}{N}{Anlagen mit Freileitungen} &
  \multicolumn{1}{N@{}}{Preis} \\\cmidrule(lr){2-7}
 & \multicolumn{1}{R{6em}}{Betriebs"-spannung~\unit{kV}} &
   \multicolumn{1}{R{6em}}{Lösch"-spannung~\unit{kV}} &
   \multicolumn{1}{R{6em}}{Wechsel"-spannung~\unit{kV}} &
   \multicolumn{1}{R{6em}}{Ansprech"-spannung~\unit{kV}} &
   \multicolumn{1}{R{6em}}{Restspannung \unit{kV}} &
   \multicolumn{1}{R{6em}}{Gewicht netto~\unit{kg}} & \multicolumn{1}{N@{}}{DM} \\
   \cmidrule(r){1-1}\cmidrule(lr){2-2}\cmidrule(lr){3-3}\cmidrule(lr){4-4}%
   \cmidrule(lr){5-5}\cmidrule(lr){6-6}\cmidrule(lr){7-7}\cmidrule(l){8-8}
 \ldots \\\bottomrule
\end{tabular}

\end{document}
