diff --git a/scripts/base_network.py b/scripts/base_network.py
index bb8d0dde..e0337cb9 100644
--- a/scripts/base_network.py
+++ b/scripts/base_network.py
@@ -119,13 +119,15 @@ def _set_electrical_parameters_lines(lines):
 
     lines['s_max_pu'] = snakemake.config['lines']['s_max_pu']
     lines.loc[lines.under_construction.astype(bool), 'num_parallel'] = 0.
-    lines['s_nom'] = (
-        np.sqrt(3) * n.lines['type'].map(n.line_types.i_nom) *
-        n.lines.bus0.map(n.buses.v_nom) * n.lines.num_parallel
-    )
 
     return lines
 
+def _set_lines_s_nom_from_linetypes(n):
+    n.lines['s_nom'] = (
+        np.sqrt(3) * n.lines['type'].map(n.line_types.i_nom) *
+        n.lines['v_nom'] * n.lines.num_parallel
+    )
+
 def _set_electrical_parameters_links(links):
     links['p_max_pu'] = snakemake.config['links']['s_max_pu']
     links['p_min_pu'] = -1. * snakemake.config['links']['s_max_pu']
@@ -285,6 +287,8 @@ def base_network():
 
     n = _remove_unconnected_components(n)
 
+    _set_lines_s_nom_from_linetypes(n)
+
     _apply_parameter_corrections(n)
 
     _set_countries_and_substations(n)