diff --git a/freegsnke/build_machine.py b/freegsnke/build_machine.py
index d742ef0..33841f1 100644
--- a/freegsnke/build_machine.py
+++ b/freegsnke/build_machine.py
@@ -27,6 +27,7 @@
 from freegs4e.machine import Circuit, Wall
 from freegs4e.multi_coil import MultiCoil
 
+from .copying import copy_into
 from .machine_config import build_tokamak_R_and_M
 from .machine_update import Machine
 from .magnetic_probes import Probes
@@ -596,6 +597,10 @@ def copy_tokamak(tokamak: Machine):
     new_tokamak.n_passive_coils = tokamak.n_passive_coils
     new_tokamak.n_coils = tokamak.n_coils
 
+    copy_into(tokamak, new_tokamak, "coil_resist", mutable=True, strict=False)
+    copy_into(tokamak, new_tokamak, "coil_self_ind", mutable=True, strict=False)
+    copy_into(tokamak, new_tokamak, "current_vec", mutable=True, strict=False)
+
     # add probe object attribute to tokamak (not strictly required)
     new_tokamak.probes = tokamak.probes
 
diff --git a/freegsnke/copying.py b/freegsnke/copying.py
index 7a22242..07d84c1 100644
--- a/freegsnke/copying.py
+++ b/freegsnke/copying.py
@@ -41,6 +41,11 @@ def copy_into(
     # will error if strict and attribute doesnt exist
     attribute_value = getattr(obj, attr)
 
+    # handle singletons
+    if attribute_value is None or attribute_value is True or attribute_value is False:
+        setattr(new_obj, attr, attribute_value)
+        return
+
     if mutable:
         if (
             isinstance(attribute_value, np.ndarray)