diff --git a/README.md b/README.md
index fa546ad..a8c314b 100644
--- a/README.md
+++ b/README.md
@@ -31,6 +31,8 @@ Copyright (C) 2019-2020 Joachim Stolberg
 Code: Licensed under the GNU GPL version 3 or later. See LICENSE.txt  
 Textures: CC BY-SA 3.0
 
+Many thanks to Thomas-S for his contributions
+
 
 ### Dependencies  
 Required: default, doors, bucket, stairs, screwdriver, basic_materials, tubelib2, minecart, lcdlib, safer_lua  
@@ -75,6 +77,12 @@ Available worlds will be converted to 'lsqlite3', but there is no way back, so:
 
 ### History
 
+**2020-07-31  V0.20**
+- Pull request #21: Lua Controller: Allow to get itemstring and description of 8x2000 chest contents (from Thomas-S)
+- Pull request #22: Trowel: Prevent hidden nodes from being dug (from Thomas-S)
+- Improvement: TA3 Power Terminal: Outputs max needed power in addition
+- Bugfix: Quarry: Shall not dig Techage Light Blocks
+
 **2020-07-24  V0.19**
 - Pull request #19: Refactor ICTA to use functions instead of loadstring (from Thomas-S)
 - State command added for cart-, node-, and player detectors
diff --git a/basic_machines/source.lua b/basic_machines/source.lua
index 441c0eb..39bdc94 100644
--- a/basic_machines/source.lua
+++ b/basic_machines/source.lua
@@ -26,7 +26,7 @@ local networks = techage.networks
 local STANDBY_TICKS = 4
 local COUNTDOWN_TICKS = 4
 local CYCLE_TIME = 2
-local PWR_CAPA = 20
+local PWR_CAPA = 100
 
 local function formspec(self, pos, nvm)
 	return "size[4,4]"..
diff --git a/basis/lib.lua b/basis/lib.lua
index 1493fa6..4f50747 100644
--- a/basis/lib.lua
+++ b/basis/lib.lua
@@ -164,6 +164,7 @@ end
 function techage.dropped_node(node, ndef)
 	if node.name == "air" then return end
 	--if ndef.buildable_to == true then return end
+	if not ndef.diggable then return end
 	if ndef.drop == "" then return end
 	if type(ndef.drop) == "table" then
 		return handle_drop(ndef.drop)
diff --git a/lamps/lightblock.lua b/lamps/lightblock.lua
index b4f089a..93a064b 100644
--- a/lamps/lightblock.lua
+++ b/lamps/lightblock.lua
@@ -39,6 +39,7 @@ minetest.register_node("techage:lightblock", {
 	floodable = true,
 	is_ground_content = false,
 	groups = {not_in_creative_inventory=1},
+	drop = "",
 })
 
 function techage.light_ring(center_pos, on, large)
diff --git a/power/distribution.lua b/power/distribution.lua
index 0c624a5..610e7e0 100644
--- a/power/distribution.lua
+++ b/power/distribution.lua
@@ -147,3 +147,16 @@ function techage.power.power_distribution(network, tlib_type, netID, cycle_time)
 		set_taken_values(network.con2, 0, tlib_type)
 	end
 end
+
+-- determine the maxiumum needed power of all con1 consumers
+function techage.power.get_con1_sum(network, tlib_type)
+	local sum = 0
+	for _,v in ipairs(network.con1 or {}) do
+		local nvm = techage.get_nvm(v.pos)
+		local def = nvm[tlib_type] -- power related network data
+		if def and def["cstate"] ~= STOPPED then
+			sum = sum + v.nominal
+		end
+	end
+	return sum
+end
diff --git a/power/power_terminal2.lua b/power/power_terminal2.lua
index 01fcb7e..6bb61cc 100644
--- a/power/power_terminal2.lua
+++ b/power/power_terminal2.lua
@@ -188,11 +188,14 @@ end
 
 local function get_state(netw)
 	local state = ""
+	local needed = techage.power.get_con1_sum(netw, "ele1") or 0
 	
 	if #(netw.gen1 or {}) + #(netw.gen2 or {}) == 0 then
 		state = S("No power grid or running generator!")
+	elseif needed > (netw.available1 or 0) then
+		state = S("Probably too many consumers (")..needed..S(" ku is needed!)")
 	elseif (netw.num_nodes or 0) < techage.networks.MAX_NUM_NODES then
-		state = S("Number of power grid blocks")..": "..(netw.num_nodes or 0)
+		state = S("Number of power grid blocks")..": "..(netw.num_nodes or 0)..",  "..S("Max. needed power")..": "..needed.. " ku"
 	else
 		state = S("To many blocks in the power grid!")
 	end