diff --git a/app/models/room.rb b/app/models/room.rb
index 1736f80c64..5620e78113 100644
--- a/app/models/room.rb
+++ b/app/models/room.rb
@@ -30,7 +30,7 @@ class Room < ApplicationRecord
   validates :name, presence: true
   validates :friendly_id, presence: true, uniqueness: true
   validates :meeting_id, presence: true, uniqueness: true
-  validates :voice_bridge, uniqueness: true
+  # validates :voice_bridge, uniqueness: true
   validates :presentation,
             content_type: Rails.configuration.uploads[:presentations][:formats],
             size: { less_than: Rails.configuration.uploads[:presentations][:max_size] }
@@ -38,7 +38,7 @@ class Room < ApplicationRecord
   validates :name, length: { minimum: 1, maximum: 255 }
   validates :recordings_processing, numericality: { only_integer: true, greater_than_or_equal_to: 0 }
 
-  before_validation :set_friendly_id, :set_meeting_id, :set_voice_brige, on: :create
+  before_validation :set_friendly_id, :set_meeting_id, :set_voice_bridge, on: :create
   before_save :scan_presentation_for_virus
 
   after_create :create_meeting_options
@@ -103,18 +103,22 @@ def set_meeting_id
     retry
   end
 
-  # Create unique pin for voice brige max 10^x - x*0.1 unique ids (x = len of pin)
+  # Create unique pin for voice brige max 10^x - 10^(x-1) unique ids (x = len of pin)
   # No leading Zeros
-  def set_voice_brige
+  def set_voice_bridge
+    self.voice_bridge = nil
+
     return if Rails.application.config.voice_bridge_phone_number.nil?
 
     pin_len = Rails.application.config.sip_pin_length
     max_pins = 10.pow(pin_len) - 10.pow(pin_len - 1) - 1
 
-    return if Room.all.where.not(voice_bridge: nil).length > max_pins # Check if a pins are left
+    return if Room.all.where.not(voice_bridge: nil).length >= max_pins # Check if pins are left
 
-    id = SecureRandom.random_number(10.pow(pin_len) - 1) # Pick random pin
-    id = ((id + 1) % max_pin) + 10.pow(pin_len - 1) while Room.exists?(voice_bridge: id) || id < 10.pow(pin_len - 1) # Take next free pin
+    # Pick random pin
+    id = SecureRandom.random_number(10.pow(pin_len) - 1)
+    # Ensure uniqueness and if not take next free pin
+    id = ((id + 1) % max_pins) + 10.pow(pin_len - 1) while Room.exists?(voice_bridge: id) || id < 10.pow(pin_len - 1)
 
     self.voice_bridge = id
   end
diff --git a/db/migrate/20230321125010_add_voice_brige_to_romms.rb b/db/migrate/20230321125010_add_voice_brige_to_romms.rb
index 2b87a390d9..829e427e07 100644
--- a/db/migrate/20230321125010_add_voice_brige_to_romms.rb
+++ b/db/migrate/20230321125010_add_voice_brige_to_romms.rb
@@ -3,6 +3,6 @@
 class AddVoiceBrigeToRomms < ActiveRecord::Migration[7.0]
   def change
     add_column :rooms, :voice_bridge, :integer, null: true, default: nil
-    add_index :rooms, :voice_bridge, unique: true
+    add_index :rooms, :voice_bridge
   end
 end
diff --git a/spec/factories/room_factory.rb b/spec/factories/room_factory.rb
index e94153021a..7258496f58 100644
--- a/spec/factories/room_factory.rb
+++ b/spec/factories/room_factory.rb
@@ -21,6 +21,6 @@
     user
     name { Faker::Educator.course_name }
     last_session { nil }
-    # meeting_id & friendly_id are set automatically using before_validation
+    # meeting_id & friendly_id & voice_brige are set automatically using before_validation
   end
 end
diff --git a/spec/models/room_spec.rb b/spec/models/room_spec.rb
index 691d47f7e4..c5b7292c3a 100644
--- a/spec/models/room_spec.rb
+++ b/spec/models/room_spec.rb
@@ -30,7 +30,7 @@
     it { is_expected.to validate_length_of(:name).is_at_least(1).is_at_most(255) }
     it { is_expected.to validate_numericality_of(:recordings_processing).only_integer.is_greater_than_or_equal_to(0) }
 
-    # Can't test validation on friendly_id and meeting_id due to before_validations
+    # Can't test validation on friendly_id, meeting_id and voice_brige due to before_validations
 
     context 'presentation validations' do
       it 'fails if the presentation is not a valid extension' do
@@ -84,6 +84,23 @@
         expect { duplicate_room.meeting_id = room.meeting_id }.to change { duplicate_room.valid? }.to false
       end
     end
+
+    describe '#set_voice_brige' do
+      it 'sets a rooms voice_brige before creating' do
+        if Rails.application.config.voice_bridge_phone_number.nil?
+          expect(room.voice_bridge).to be_nil
+        else
+          expect(room.voice_bridge).to be_present
+        end
+      end
+
+      it 'prevents duplicate voice_briges' do
+        duplicate_room = create(:room)
+        unless Rails.application.config.voice_bridge_phone_number.nil?
+          expect { duplicate_room.voice_bridge = room.voice_bridge }.to change { duplicate_room.valid? }.to false
+        end
+      end
+    end
   end
 
   describe 'before_save' do