diff --git a/Nasal/electrical.nas b/Nasal/electrical.nas
index 147f74ec..e58e2939 100644
--- a/Nasal/electrical.nas
+++ b/Nasal/electrical.nas
@@ -169,8 +169,6 @@ var master_elec = func {
 	extpwr_on = getprop("/controls/switches/cart");
 	stateL = getprop("/engines/engine[0]/state");
 	stateR = getprop("/engines/engine[1]/state");
-	xtieL = getprop("/controls/electrical/xtie/xtieL");
-	xtieR = getprop("/controls/electrical/xtie/xtieR");
 	ac1 = getprop("/systems/electrical/bus/ac1");
 	ac2 = getprop("/systems/electrical/bus/ac2");
 	ac_ess = getprop("/systems/electrical/bus/ac-ess");
@@ -231,16 +229,19 @@ var master_elec = func {
 		setprop("/controls/electrical/xtie/xtieL", 0);
 	}
 	
+	xtieL = getprop("/controls/electrical/xtie/xtieL");
+	xtieR = getprop("/controls/electrical/xtie/xtieR");
+	
 	# Left DC bus yes?
 	if (stateL == 3 and gen1_sw and !gen1_fail) {
 		setprop("/systems/electrical/bus/dc1", dc_volt_std);
 		setprop("/systems/electrical/bus/dc-ess", dc_volt_std);
 		setprop("/systems/electrical/bus/dc1-amps", dc_amps_std); 
-	} else if (extpwr_on and gen_ext_sw) {
+	} else if (extpwr_on and gen_ext_sw and apu_ext_crosstie_sw) {
 		setprop("/systems/electrical/bus/dc1", dc_volt_std);
 		setprop("/systems/electrical/bus/dc-ess", dc_volt_std);
 		setprop("/systems/electrical/bus/dc1-amps", dc_amps_std); 
-	} else if (gen_apu and !genapu_fail) {
+	} else if (gen_apu and !genapu_fail and apu_ext_crosstie_sw) {
 		setprop("/systems/electrical/bus/dc1", dc_volt_std);
 		setprop("/systems/electrical/bus/dc-ess", dc_volt_std);
 		setprop("/systems/electrical/bus/dc1-amps", dc_amps_std); 
@@ -265,11 +266,11 @@ var master_elec = func {
 		setprop("/systems/electrical/bus/dc2", dc_volt_std);
 		setprop("/systems/electrical/bus/dc-ess", dc_volt_std);
 		setprop("/systems/electrical/bus/dc2-amps", dc_amps_std); 
-	} else if (extpwr_on and gen_ext_sw) {
+	} else if (extpwr_on and gen_ext_sw and apu_ext_crosstie_sw) {
 		setprop("/systems/electrical/bus/dc2", dc_volt_std);
 		setprop("/systems/electrical/bus/dc-ess", dc_volt_std);
 		setprop("/systems/electrical/bus/dc2-amps", dc_amps_std); 
-	} else if (gen_apu and !genapu_fail) {
+	} else if (gen_apu and !genapu_fail and apu_ext_crosstie_sw) {
 		setprop("/systems/electrical/bus/dc2", dc_volt_std);
 		setprop("/systems/electrical/bus/dc-ess", dc_volt_std);
 		setprop("/systems/electrical/bus/dc2-amps", dc_amps_std); 
@@ -292,9 +293,9 @@ var master_elec = func {
 	# Left AC bus yes?
 	if (stateL == 3 and gen1_sw and !gen1_fail) {
 		setprop("/systems/electrical/bus/ac1", ac_volt_std);
-	} else if (extpwr_on and gen_ext_sw) {
+	} else if (extpwr_on and gen_ext_sw and apu_ext_crosstie_sw) {
 		setprop("/systems/electrical/bus/ac1", ac_volt_std);
-	} else if (gen_apu and !genapu_fail) {
+	} else if (gen_apu and !genapu_fail and apu_ext_crosstie_sw) {
 		setprop("/systems/electrical/bus/ac1", ac_volt_std);
 	} else if (apu_ext_crosstie_sw == 1 and xtieL) {
 		setprop("/systems/electrical/bus/ac1", ac_volt_std);
@@ -307,9 +308,9 @@ var master_elec = func {
 	# Right AC bus yes?
 	if (stateR == 3 and gen2_sw and !gen2_fail) {
 		setprop("/systems/electrical/bus/ac2", ac_volt_std);
-	} else if (extpwr_on and gen_ext_sw) {
+	} else if (extpwr_on and gen_ext_sw and apu_ext_crosstie_sw) {
 		setprop("/systems/electrical/bus/ac2", ac_volt_std);
-	} else if (gen_apu and !genapu_fail) {
+	} else if (gen_apu and !genapu_fail and apu_ext_crosstie_sw) {
 		setprop("/systems/electrical/bus/ac2", ac_volt_std);
 	} else if (apu_ext_crosstie_sw == 1  and xtieR) {
 		setprop("/systems/electrical/bus/ac2", ac_volt_std);
diff --git a/Nasal/fuel.nas b/Nasal/fuel.nas
index d486cc33..a73052af 100644
--- a/Nasal/fuel.nas
+++ b/Nasal/fuel.nas
@@ -160,7 +160,7 @@ var master_fuel = func {
 	gravityfeedL = getprop("/systems/fuel/gravityfeedL");
 	gravityfeedR = getprop("/systems/fuel/gravityfeedR");
 	
-	if ((getprop("/fdm/jsbsim/propulsion/tank[1]/contents-lbs") >= 50) and tank1feed0 and tank1feed1 and !gravityfeedL and !gravityfeedR) {
+	if ((getprop("/fdm/jsbsim/propulsion/tank[1]/contents-lbs") >= 50) and tank1feed and !gravityfeedL and !gravityfeedR) {
 		setprop("/systems/fuel/only-use-ctr-tank", 1);
 	} else {
 		setprop("/systems/fuel/only-use-ctr-tank", 0);
diff --git a/revision.txt b/revision.txt
index 8799d84b..e8dadcda 100644
--- a/revision.txt
+++ b/revision.txt
@@ -1 +1 @@
-1537
\ No newline at end of file
+1540
\ No newline at end of file