diff --git a/src/Entity/EDA/EDACategoryInfo.php b/src/Entity/EDA/EDACategoryInfo.php
index 0163dfb3..40b3ff64 100644
--- a/src/Entity/EDA/EDACategoryInfo.php
+++ b/src/Entity/EDA/EDACategoryInfo.php
@@ -58,7 +58,7 @@ class EDACategoryInfo
     /** @var bool|null If this is set to true, then this part will be excluded in the simulation */
     #[Column(type: Types::BOOLEAN, nullable: true)]
     #[Groups(['full', 'category:read', 'category:write', 'import'])]
-    private ?bool $exclude_from_sim = true;
+    private ?bool $exclude_from_sim = null;
 
     /** @var string|null The KiCAD schematic symbol, which should be used (the path to the library) */
     #[Column(type: Types::STRING, nullable: true)]
diff --git a/src/Services/EDA/KiCadHelper.php b/src/Services/EDA/KiCadHelper.php
index 4b7c5e5a..3a613fe7 100644
--- a/src/Services/EDA/KiCadHelper.php
+++ b/src/Services/EDA/KiCadHelper.php
@@ -189,7 +189,7 @@ class KiCadHelper
             "symbolIdStr" => $part->getEdaInfo()->getKicadSymbol() ?? $part->getCategory()?->getEdaInfo()->getKicadSymbol() ?? "",
             "exclude_from_bom" => $this->boolToKicadBool($part->getEdaInfo()->getExcludeFromBom() ?? $part->getCategory()?->getEdaInfo()->getExcludeFromBom() ?? false),
             "exclude_from_board" => $this->boolToKicadBool($part->getEdaInfo()->getExcludeFromBoard() ?? $part->getCategory()?->getEdaInfo()->getExcludeFromBoard() ?? false),
-            "exclude_from_sim" => $this->boolToKicadBool($part->getEdaInfo()->getExcludeFromSim() ?? $part->getCategory()?->getEdaInfo()->getExcludeFromSim() ?? true),
+            "exclude_from_sim" => $this->boolToKicadBool($part->getEdaInfo()->getExcludeFromSim() ?? $part->getCategory()?->getEdaInfo()->getExcludeFromSim() ?? false),
             "fields" => []
         ];