No. You will not lose access to electricity by switching electricity provider.
When you switch to iO Energy our customer service team will simply inform your current supplier that you wish to switch, and we will work with them to transfer responsibility for your electrical supply without interruption.
The only way that you might interrupt your supply is if you tell your current electrical supplier that you want to close your account with them on Day 'X' and separately tell us that you wish to create an account on Day 'Y.' If there is a gap between these two dates there could be an interruption to your connection (so don't do this).