diff --git a/internal/server/handlers.go b/internal/server/handlers.go
index 40cf4ce..c9d04ca 100644
--- a/internal/server/handlers.go
+++ b/internal/server/handlers.go
@@ -278,9 +278,9 @@ func synthesizePSUVoltageSensors(hw *models.HardwareConfig) []models.SensorReadi
 		return nil
 	}
 	const (
-		nominalV = 220.0
-		minV     = nominalV * 0.9 // 198V
-		maxV     = nominalV * 1.1 // 242V
+		nominalV = 230.0
+		minV     = nominalV * 0.9 // 207V
+		maxV     = nominalV * 1.1 // 253V
 	)
 	out := make([]models.SensorReading, 0, len(hw.PowerSupply))
 	for _, psu := range hw.PowerSupply {
diff --git a/web/static/js/app.js b/web/static/js/app.js
index 374cac2..05327c8 100644
--- a/web/static/js/app.js
+++ b/web/static/js/app.js
@@ -1111,9 +1111,9 @@ function renderSensors(sensors) {
                 valueStr = s.status;
             }
 
-            // Highlight PSU mains voltage deviations from nominal 220V (±10%).
+            // Highlight PSU mains voltage deviations from nominal 230V (±10%).
             let extraClass = '';
-            if (isPSUVoltage && Number.isFinite(s.value) && (s.value < 198 || s.value > 242)) {
+            if (isPSUVoltage && Number.isFinite(s.value) && (s.value < 207 || s.value > 253)) {
                 extraClass = ' voltage-out-of-range';
             }