Is it safe to implement a split power supply from two identical AC/DC adapters?

If I have two identical AC/DC adapters(Such as laptop adapters) can I achieve this as in the following illustration? Would it be safe?:

Answer

There is nothing fundamentally wrong with what you propose. Any purpose built dual output power supply is essentially the same thing. So using this approach can be a workable scheme to achieve a dual output + and - rail output.

One thing that must be considered here is that the two power supplies need to have fully floating outputs.

There are a number of serious disadvantages however. Here are some things to consider:

1. 
   

   Can the target device powered by this scheme survive safely if one or the other output becomes 0V because one of the wall warts gets unplugged.

   
   


2. 
   

   A purpose built dual output power supply will have certain fault detection features that will apply equally to both the + and - outputs which will safely shut things down in case of problems. One example would be a primary side safety fuse that blows and disconnects both the outputs from the mains.

   
   


3. 
   
   

   Invariably a dual output supply will share some common components and circuits for supporting both outputs. In particular this would be in the mains conversion and isolation circuit. This can lead to a smaller overall design than using two completely separate power supplies.