diff --git a/pcb_calculator/calculator_panels/panel_electrical_spacing_iec60664_base.cpp b/pcb_calculator/calculator_panels/panel_electrical_spacing_iec60664_base.cpp
index 0ceb3ba533..4b9bd4dc11 100644
--- a/pcb_calculator/calculator_panels/panel_electrical_spacing_iec60664_base.cpp
+++ b/pcb_calculator/calculator_panels/panel_electrical_spacing_iec60664_base.cpp
@@ -53,7 +53,7 @@ PANEL_ELECTRICAL_SPACING_IEC60664_BASE::PANEL_ELECTRICAL_SPACING_IEC60664_BASE(
 
 	m_staticText52111 = new wxStaticText( sbSizerTop->GetStaticBox(), wxID_ANY, _("Overvoltage category:"), wxDefaultPosition, wxDefaultSize, 0 );
 	m_staticText52111->Wrap( -1 );
-	m_staticText52111->SetToolTip( _("OVC I: Equipments with no direct connection to mains supply\n\nOVC II: Energy-consuming equipment to be supplied from the fixed installation. (eg: appliances, portable tools, household loads). OVCIII applies if there are reliability and avaibility requirements\n\nOVC III :  Equipements in fixed installation with reliability and avaibility requirements. (eg: electrical switches, equipment for industrial use)\n\nOVC IV: Equipments at the origin of the installation (eg: electricity meters, primary overcurrent protection devices)") );
+	m_staticText52111->SetToolTip( _("OVC I: Equipment with no direct connection to mains supply\n\nOVC II: Energy-consuming equipment to be supplied from the fixed installation. (eg: appliances, portable tools, household loads). OVCIII applies if there are reliability and avaibility requirements\n\nOVC III :  Equipment in fixed installations with reliability and avaibility requirements. (eg: electrical switches, equipment for industrial use)\n\nOVC IV: Equipment at the origin of the installation (eg: electricity meters, primary overcurrent protection devices)") );
 
 	fgSizer111->Add( m_staticText52111, 0, wxALIGN_CENTER_VERTICAL|wxBOTTOM|wxRIGHT|wxLEFT, 5 );
 
@@ -82,7 +82,7 @@ PANEL_ELECTRICAL_SPACING_IEC60664_BASE::PANEL_ELECTRICAL_SPACING_IEC60664_BASE(
 
 	m_staticText111111 = new wxStaticText( sbSizerTop->GetStaticBox(), wxID_ANY, _("Impulse voltage:"), wxDefaultPosition, wxDefaultSize, 0 );
 	m_staticText111111->Wrap( -1 );
-	m_staticText111111->SetToolTip( _("Given the rated voltage and the overvoltage category, a device should withstand this value whithout a breakdown of insulation. This impulse voltage is a standard 1.2/50µs wave") );
+	m_staticText111111->SetToolTip( _("Given the rated voltage and the overvoltage category, a device should withstand this value without a breakdown of insulation. This impulse voltage is a standard 1.2/50µs wave") );
 
 	fgSizerTopRight->Add( m_staticText111111, 0, wxALIGN_CENTER_VERTICAL|wxALL, 5 );
 
diff --git a/pcb_calculator/calculator_panels/panel_electrical_spacing_iec60664_base.fbp b/pcb_calculator/calculator_panels/panel_electrical_spacing_iec60664_base.fbp
index b9c8972370..a985309007 100644
--- a/pcb_calculator/calculator_panels/panel_electrical_spacing_iec60664_base.fbp
+++ b/pcb_calculator/calculator_panels/panel_electrical_spacing_iec60664_base.fbp
@@ -458,7 +458,7 @@
                                                             <property name="style"></property>
                                                             <property name="subclass">; ; forward_declare</property>
                                                             <property name="toolbar_pane">0</property>
-                                                            <property name="tooltip">OVC I: Equipments with no direct connection to mains supply&#x0A;&#x0A;OVC II: Energy-consuming equipment to be supplied from the fixed installation. (eg: appliances, portable tools, household loads). OVCIII applies if there are reliability and avaibility requirements&#x0A;&#x0A;OVC III :  Equipements in fixed installation with reliability and avaibility requirements. (eg: electrical switches, equipment for industrial use)&#x0A;&#x0A;OVC IV: Equipments at the origin of the installation (eg: electricity meters, primary overcurrent protection devices)</property>
+                                                            <property name="tooltip">OVC I: Equipment with no direct connection to mains supply&#x0A;&#x0A;OVC II: Energy-consuming equipment to be supplied from the fixed installation. (eg: appliances, portable tools, household loads). OVCIII applies if there are reliability and avaibility requirements&#x0A;&#x0A;OVC III :  Equipment in fixed installations with reliability and avaibility requirements. (eg: electrical switches, equipment for industrial use)&#x0A;&#x0A;OVC IV: Equipment at the origin of the installation (eg: electricity meters, primary overcurrent protection devices)</property>
                                                             <property name="window_extra_style"></property>
                                                             <property name="window_name"></property>
                                                             <property name="window_style"></property>
@@ -623,7 +623,7 @@
                                                             <property name="style"></property>
                                                             <property name="subclass">; ; forward_declare</property>
                                                             <property name="toolbar_pane">0</property>
-                                                            <property name="tooltip">Given the rated voltage and the overvoltage category, a device should withstand this value whithout a breakdown of insulation. This impulse voltage is a standard 1.2/50µs wave</property>
+                                                            <property name="tooltip">Given the rated voltage and the overvoltage category, a device should withstand this value without a breakdown of insulation. This impulse voltage is a standard 1.2/50µs wave</property>
                                                             <property name="window_extra_style"></property>
                                                             <property name="window_name"></property>
                                                             <property name="window_style"></property>